Emails to the Multihull Mail List from Joseph Oster Mar 1996 thru Nov 2002

NOTE 1: The MhMl Archives at steamradio.com appear to be incomplete prior to Dec 9, 2000. The 218 emails on this page are from my personal archives, consisting of Thunderbird folders, dating back to when I (Joseph Oster) joined MhMl on Feb 24, 1996; at that time, the list was hosted at ronin.com. These emails were selected using a search criteria of "from contains joseph oster". It would be nice, of course, to have the full archive restored in a format more accessible than this, but that is a big project for another day.

NOTE 2: begin HarryProa emails - 1st HarryProa web page - 1st "U" web page
notes:


Subject: Big proas, little trimarans... From: Joseph Oster <oster_at_wingo.com> Date: Thu, 07 Mar 1996 08:03:08 -0800 To: Ted Warren <warren_at_nexen.com> CC: multihulls_at_ronin.com Hello Ted! Hi everyone. Let me introduce myself. I was a 1/3rd partner in Dick Newick's great 50' trimaran Moxie from 1987 thru 1989 when I lived on Martha's Vineyard. My mates and I set a record in '87 racing from Newport, RI to Bermuda: 64 hours, 49 minutes! Probably still stands. I also claim a record (in Moxie) for the fastest time around the island of Martha's Vineyard: 4 hours, 54 minutes (started in a 25 knot October gale)! I raced in the 'Tashmoo Dash' with Ted Warren on his Newick Panache in 1986. These days I own a 24' Crowther Buccaneer trimaran that I am restoring from pieces in a boat builder's Coop here in Sausalito, CA. (Yes, where Aurther Piver designed and built his trimarans.) The 24' Buccanneer has two full length births hanging, one on each side, in "wings" extending from the main hull. It uses 4.5" aluminum tubes as crossarms. While demountable, it is a job to be measured in _days_, not hours. The boat seems very relevant to the subject of your Ronin28 project; the accomodation in the main hull of this little tri is really quite comfortable. To say the least, working on this boat has been a humbling experience. Many could have done it faster and cheaper, yet for me it has taken two years and $20+K and the sails have yet to be raised for the first time! Boat-building projects are _VERY_ demanding and best completed in a year or less because otherwise time and money is spent repairing boat yard damage! I'll let you know when I get her sailing; should be "real soon now"; launched three months ago! As to proas, I've been dreaming of a _BIG_ proa ever since (reluctantly) giving up Moxie... As you know, I sailed with Russell Brown quite a bit on his proa Kauri during those years on the Vineyard. My friend Porter Thompson bought Kauri from Russell and still keeps the boat on the Vineyard. I've been working on a design for a sixty-eight foot proa for several years and have engaged the services of naval architect Jim Antrim (designer of the trimaran Aotea) to complete a fully engineered design this year. BTW, I felt that Charles Chiodi's "slap" at Jim Antrim in his latest editorial ("1995: The Year That Was") was harsh and unnecessary, especially in light of his eloquent defense of Jim a few pages later (p. 11) in reply to a vicious letter. I'll cut this short for now with just one request... Please keep in mind that some people (like me) subscribe to more than one mailing list and have a _LOT_ of EMail to wade through each day. Since joining this list a couple weeks ago, the volume of traffic from "multihulls_at_ronin.com" has been nearly overwhelming. While it's great to have this forum available, it is tough to wade through dozens of messages per day, especially those that copy in full the message to which they are replying and add only a one-line comment. Excerpts are fine; full text is not necessary! Check out my web page at http://www.JosephOster.com It has links to "Pacific Proa Company" (my corporation), a Jim Antrim page (both in progress), and some other good sailing links. Best regards to all, Joseph Oster (AKA Jai Gopal Singh)
Subject: Re: Big proas, little trimarans... From: Joseph Oster <oster_at_wingo.com> Date: Sun, 10 Mar 1996 11:26:16 -0800 To: Ted Warren <warren_at_nexen.com> CC: multihulls_at_ronin.com Ted Warren wrote: > > Good to hear from you. Have you kept track of your hours? The Ronin28 project > > will want to estimate time to build at some point, and it would be good to > > have input from actual building experiences. What kind of pieces did you > > have to start with? Hopefully you are enjoying the project as you go. The 24' trimaran project began for me as a main hull on a trailer with two floats in a lot six blocks away where someone was threatening to burn them! A cursory inspection showed all three hulls to be very carefully designed and built and in basically excellent condition... After years of _rapid_ service on the Bay (following a reputed trip down the coast from Vancouver where she was built), the boat had been hauled for a re-fit which had bogged down after three years in the Coop yard. That's when I bought the boat; February '94, a good time (winter) to pass a boat dream from one owner to the next... At the time, I was in a high-pressure programming job that paid well enough to let me believe that if I just hired the right people and threw money at the project, I would be sailing in months, if not weeks! Hah! The boat _was_ in good shape, yet needed many layers of paint removed; we re-finished everything inside and out, added two layers of S-glass to the ama decks, one layer inside the main hull (West System). Also did some 2" foam/carbon stiffening of the "cat-walks" on each side of the cabin going foward, and foam/ply hard points for pad-eyes, cleats, etc. Painted with Interlux Brightside Polyurethane (Dark Blue hulls, Dusk Grey decks; nice!). The crossarm tubes and been cut at the mainhull joints and needed new internal aluminum sleeves. The previous owner and I had quickly agreed that rudders on each float would work better than the old one on the main hull transom (which is now a protected outboard mount!) so I designed gudgeons for the ama sterns and kick-up rudder boxes to hold Hobbie 21 rudders... The bar that connects them is attached at the trailing edge of the rudder box; there is no tiller, per say. Three steering systems come to mind, with the easiest (and first) being a simple tiller extension attached to the rudder bar. I'll probably also have a simple(?) cable/wheel system... Along with rudder changes (and restoring the mast to 34' from 30'), I naturally took the liberty of completely re-arranging the deck layout. Two original Barient winches are placed on the cabin deck, one on each side of the companionway, and used for halyards as well as jib sheets (which now lead to the roof). With no rudder in the way, I will try to sail without a boom at first; 3:1/6:1 mainsheet attached way aft and Moxie-style "vangs" pulling the mainsail to the ama sterns. Hours on the project are on little pieces of paper in a big envelope. Not easily available and possibly not relevent since we each manage things differently. Though I had wished someone would, no one yet has taken full charge of the project and completed it for me. It sits there now at the dock, begging my personal attention, "finish this, do that!". At least I have more time now and the weather here in Sausalito is much better than New England this time of year. > > Are you designing an Atlantic Proa, as in RN, or a Pacific Proa, as in RB? Proas > > are very compelling boats with their simplicity and symmetery. Any ideas on > > stability? At the risk of taking heat for commercial self-interest, as my web page explains (http://www.pacificproa.com/), I am interested in big Pacific style (Russell Brown) proas. At http://www.pacificproa.com/flyproa.html you will see a description from Canoes of Oceania and a link showing Dick Newick's 'Cheers' Atlantic proa to illustrate the difference (windward vs. leeward proa). > > my 38' Newick "Alisha Lynn" nee "Panache" was destroyed... Alas! Very sorry to hear that. Amazing how that stuff can happen. I saw that Joe Colpit's old boat Alien was destroyed last fall after he had sold it. Beautiful boats, terrible losses. The sudden, short, and extremely intense squall that flipped Aotea last spring in these parts was a weather scare that surprised and shook us all. re "development boat projects" - I just tuned in; what have you been up to? regards, Joseph
Subject: Water Ballast for proas From: Joseph Oster <oster_at_wingo.com> Date: Mon, 11 Mar 1996 10:24:23 -0800 To: Ted Warren <warren_at_nexen.com> CC: multihulls_at_ronin.com re "A ballasted multihull, with 33% weight in ballast..." - That's a very significant percentage! In a Pacific Proa with 30% of its weight (and displacement) in the windward hull, righting moment can be improved considerably with water ballast weighing 50% or less of the ama's displacement. 50% X 30% = _15%_ of total boat weight! In the 68' version I have in mind, this amounts to nearly 300 gallons or 2,400 lbs. (maximum). 15% weight for 50% increase in stability! Yes, water ballast makes sense to me in a proa, especially since it stays on the same side of the boat when tacking, though is likely pumped end-to-end, keeping the weight aft. Joseph
Subject: Re: Water Ballast for proas From: Joseph Oster <oster_at_wingo.com> Date: Mon, 11 Mar 1996 11:36:26 -0800 To: Ted Warren <warren_at_nexen.com> CC: multihulls_at_ronin.com To be very precise about this, "33% weight in ballast" implies that the water ballast weighs one half of the un-ballasted boat weight, correct? When I said "water ballast weighing 15% of total boat weight", it must be compared to 50% of total boat weight implied by your statement. Using that perspective, I'll say it this way: 13% percent weight in water ballast in the windward hull of a Pacific proa (15% of un-ballasted boat, 50% of ama displacement) increases stability (righting moment) by 50% (!!!) Joseph
Subject: Re: water ballast From: Joseph Oster <oster_at_wingo.com> Date: Thu, 14 Mar 1996 09:21:51 -0800 To: Ted Warren <warren_at_nexen.com> CC: multihulls_at_ronin.com Ted Warren wrote: > > Ballast never wins over form stability. Well, Ted, the reports on the Gougeon-32 have been very interesting nevertheless... Apparently much more competitive than I would have guessed. Now I know you think that "Proas need some work before going public" and this hasn't much to do with the Ronin28 project. Still, I'd like to point out that a Pacific proa may be the most ideal configuration possible for benefiting from water ballast for the following reasons: 1) With only about 30% of Design Displacement ('DD') to windward in the first place, this form gets a much higher percentage increase in stability for much less total percentage of ballast than other boats. For example, if the windward hull is "flooded to the waterline", taking on another 30% of 'DD', this results in 46% to windward and 54% to leeward (on the Main hull), much closer to a catamaran, with a 100% increase in initial stability! The ballast would be 23% of total weight, quite good compared to a monohull or even the Gougeon-32. And the crossams would be no heavier than needed for a catamaran of similar weight. 2) In the proa, the ballast always stays on the same side of the boat, reducing the danger of capsize from having it on the wrong side. 3) The proa can be wide, putting ballast where it does the most good. Work the Bruce numbers with equal weight boats and note that the proa main hull will have a longer waterline than the catamaran and be better in light air... Statements about design negligence, lawsuits, "100:1 I would guess", and the unsuitability of proas seem heavy-handed to me. As you well know, injuries can occur for many reasons when sailing. Blaming the designer for poor sailing practices doesn't go very far with me. regards, Joseph Oster
Subject: Re: Water Ballast From: Joseph Oster <oster_at_wingo.com> Date: Fri, 15 Mar 1996 16:48:10 -0800 To: John Shuttleworth <johns_at_bilpin.co.uk> CC: multihulls_at_ronin.com Greetings Mr. Shuttleworth, Welcome to this list; I'm new here myself. Had the pleasure of meeting you at the 1988 Multihull Symposium in Newport, RI, at the end of the CSTAR. We spoke about possibilities for auto- trimming a wing mast, among other things. I look forward to your discussion of the water ballast issue. Clearly monohulls have used the concept of ballast with great effectiveness, yet every expert concludes that a multihull is always better without ballast... There is a mystery here for me. Is ballast only effective (as in monohulls) when it is more than 40% of total displacement? What about that area where the ballast is only 10..20% of total weight and on a long multihull lever arm? Especially on the Pacific proa where such a shift brings righting moment to that of a heavier catamaran? Thanks in advance, Joseph Oster
Subject: Re: proas From: Joseph Oster <oster_at_wingo.com> Date: Tue, 19 Mar 1996 16:12:42 -0800 To: Ted Warren <warren_at_nexen.com> CC: multihulls_at_ronin.com, AntrimNA_at_aol.com Hi Ted, Thanks for clearing the air and making such a strong statement in favor of proas. I often feel that they are dismissed as quickly by the multihull community as multihulls were thirty years ago by the monohull connoussiers of the day. I agree that a 28' proa is probably not a great idea, especially if any accommodation is desired, other than the camping style exemplified in Kurt Hughes' clever twenty-six footer. The three 37' footers that Russell Brown has built have barely enough space to qualify as minimum, IMHO (and my cruising plans call for _much_ more; equivalent in weight and space, for example, to a typical cruising catamaran of 40..47'). The thing about proas (and I'm always refering to Pacific proas) that makes them attractive in large sizes is the very same thing that works against them in smaller boats. It can be stated two ways: 1) _FOR_ large Pacific proas; they provide the most waterline length for the least amount of weight (and cost!!!). 2) _AGAINST_ small Pacific proas; less volume and displacement than catamarans or trimarans of similar length. Your 56' length is a good choice; as I mentioned previously, 68' and 14,000 lbs. displacement are the targets I'm using in my design, chosen based on a standard of cruising comfort defined by those luxurious cats in the 40..46' range (twenty+ feet shorter!!!). The name of the game, as with any other sailboat, is to balance rig horsepower against righting moment and, as you have pointed out, there are areas (light air) where proas can excel. Adding water ballast to the picture, provided the hull design is ready for the added displacement and loads, can indeed make a proa even faster and more powerful when pressed, as John Shuttleworth stated so eloquently in his recent memo: > > Once the windward hull is flying, then water ballast would improve > > speed as the wind increased - provided it did not put the hull back > > into the water. In "steady" breezes (not violent gusts), "flying" on one hull can be a very solid and delightful experience. And the bigger the boat, the less likely it is to be rolled suddenly (IMHO). regards, Joseph Oster http://www.JosephOster.com
Subject: Re: proas From: Joseph Oster <oster_at_wingo.com> Date: Wed, 20 Mar 1996 15:56:04 -0800 To: Dave Culp <daveculp_at_bdt.com> CC: multihulls_at_ronin.com Dave Culp wrote: > > It's *very* dangerous, IMHO, to use a foil for "hold-down" work. Broach > > that foil, or even stall it, and a very quick capsize results. Too fast to > > react to, since all the forces are already dialed in and large. I agree completely with you and Dan Frenette about this... > > You might think about an *air*foil, working horizontally on the cross beam, > > or outboard of the ama, creating the down force. This _IS_ something I was hoping to explore on the 68' proa but don't know how big a wing would be required (at 25 knots apparent?) to add 2000..4000 lbs. of negative lift? I had seen your web page and linked to it from my own. Way cool stuff!!!
Subject: proa discussions From: Joseph Oster <oster_at_wingo.com> Date: Sun, 24 Mar 1996 16:36:15 -0800 To: Ted Warren <warren_at_nexen.com> CC: multihulls_at_ronin.com I've sure enjoyed all the discussion of proa ideas that your (our?) interest in them has provoked. I'll have more on the subject in the months ahead as my own plans for a big boat emerge. As for now, my fiancee and I are off to Hawaii on Tuesday for vacation until April 5th! I'll do my best to sort thru the EMail and catch up when I get back. Aloha, Joseph Oster
Subject: Pacific Proas From: Joseph Oster <oster_at_wingo.com> Date: Sat, 20 Apr 1996 15:21:00 -0700 To: Peter Wynn <WYNN_at_rotko.rotol.fi> CC: multihulls_at_ronin.com Peter Wynn wrote: > > > > And why aint anybody done anything about trad Polynesian rigs, or if > > they have why aint they answered my cry for info? > > good luck Hello Peter, Your introductory note arrived while I was on vacation in Kaua'i, Hawaii, and while I spotted your note immediately ('Subj:' field), I have still to read many notes on Aerorig and water ballast that 'happened' while I was away. I have been _VERY_ interested in the Pacific Proa design myself since sailing extensively(?) with Russel Brown on the Vineyard between 1987..89. I am currently working on a design for a 68' crusing proa weighing about seven tons. The idea of keeping both rudders down all the time has occurred to me too and is even more attractive in large boats than small ones. The fact that each rudder always rotates in the same direction when tacking defines a continuous loop steering arrangment instead of the simple tillers used by Russell. I had thought dual rudders with no daggerboards to be a dubious proposition, considering the forces at work (C.E. vs. center-of- lateral-resistance, etc.), but naval architect Jim Antrim firmly believes it will work well and is the only way to go on a large yacht. I expect to have a fully-developed design sometime this summer. Check out my web page at http://www.pacificproa.com/ I agree with you (and the Europeans who "discovered" them) that these Polynesians had something really good going in the proa... regards, Joseph Oster
Subject: Pacific Proas From: Joseph Oster <oster_at_wingo.com> Date: Sun, 21 Apr 1996 20:37:15 -0700 To: Peter Wynn <WYNN_at_rotko.rotol.fi> CC: multihulls_at_ronin.com Hello again Mr. Wynn, In your note of 27 March you said: > > At the moment, the idea is to put the dagger board into the ama. > > If it lifts out of the water the boat can slide sideways. Will it > > though? Anyone out there with experience on this one? Sorry I didn't respond to this point in my earlier reply. Yes indeed, I have observed this phenomanon when sailing Russ Brown's 'Kauri'. It is a noticeable slippage that happens when the ama foil lifts out of the water that gives you warning and a few extra moments to react and steer the boat so the ama comes back down into the water, re-engaging the "daggerboard". Still, I don't plan to utilize this arrangement myself because I would like to fly the ama routinely and still resist leeway. My original plan was to use two sets of rudder/daggerboard in the main hull, one for each direction. Obviously this is alot of work when tacking (er, shunting) and is why Jim Antrim favors keeping both rudders down full time with no daggerboard at all. Apparently there have been some monohulls, including the 1987 America's Cup Golden Gate Challenge, who perfected the forward rudder concept more than I had realized. Does anyone else in this esteemed crowd have knowledge of boats with dual, fore-and-aft rudders? regards, Joseph Oster http://www.JosephOster.com http://www.pacificproa.com/
Subject: Re: Rudders and Proas From: Joseph Oster <oster_at_wingo.com> Date: Mon, 22 Apr 1996 07:15:19 -0700 To: "J. Richardson" <island_at_world.std.com> CC: multihulls_at_ronin.com J. Richardson wrote: > > > > Joseph Oster writes: Does anyone else in this esteemed crowd have knowledge > > of boats with dual, fore-and-aft rudders? > > > > First-hand design/construction/seatime experience with dual rudders, both > > continuously deployed and operable, on my 32' atlantic proa. -J. > > Richardson (island_at_world.std.com) > > Wow! Please elaborate? Do they rotate continuously in the same direction? How do you trim the forward rudder? How does it feel compared to a conventional daggerboard/rudder combo? How well do the dual rudders resist leeway? What kind of linkage mechanism do you use? Any photos or articles available? Who designed your proa? Thanks, Joseph Oster
Subject: Re: comparison From: Joseph Oster <oster_at_wingo.com> Date: Sat, 01 Feb 1997 14:57:42 -0800 To: duff <duff_at_island.net> CC: multihulls_at_ronin.com duff wrote: > > > > Here is how the Ronin 140 looks beside some other published ideas... Having just returned to this mailing and discovered the Ronin 140 project, forgive me if the following concerns have already been addressed... Does anyone but me think the displacement and proportions of this design are, well, _WAY_TOO_BIG_? "Sixteen feet of freeboard"!!!? "Nine foot thick cross-arms that a man can walk inside of"!!!? "71 tonnes"!!!?? By comparison, the 92' Enza has only four or five feet of freeboard and weighs, as I recall, around 14 tons (sorry I don't have the exact figure at hand). When I spoke with some of the crew two years ago and proposed a 120' design (proa) that weighed 27 tons they winced that it was far too heavy! Just because they are long doesn't mean (anymore) that they must weigh alot; while Enza is huge relative to most multihulls, it is still on the same scale as others near it's size such as the 75' "Double Bullet II" owned by Bob Hanel. Scaling Enza up at the ratio of 140/92 (~1.5) makes freeboard only eight feet, cross-arms less than six feet thick, and a displacement of perhaps 1/3rd that of the Ronin 140 (rough guess; I know it goes up exponentially with length but people who actually drive these big boats now believe they can be built long _AND_ light-in-weight ). These loads you are dealing with are too high because, IMHO, the boat is way too heavy. Again, apologies if this debate has already been "settled"...? Cheers, Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Cats vs. Tris vs. Proas From: Joseph Oster <oster_at_wingo.com> Date: Mon, 03 Feb 1997 19:14:11 -0800 To: John V LuValle <John.V.Luvalle_at_jpl.nasa.gov> CC: multihulls_at_RONIN.COM, 70544.3475_at_compuserve.com John V LuValle wrote: > > > > I suspect that price performance favors the proa, we just haven't seen > > enough of them (yet) to appreciate it. Though late getting into this discussion, I agree that the Pacific proa ("small" ama to windward that lifts) gives the longest possible waterline for any given displacement. And while it will have less righting moment than a catamaran of equal length (or equal weight), the Pacific proa has a good geometry for resisting pitchpoling. Joseph Oster -- http://www.JosephOster.com
Subject: Re: Introduction From: Joseph Oster <oster_at_wingo.com> Date: Tue, 11 Feb 1997 10:24:53 -0800 To: Eric Carsted Sun Microsystems - Orlando <eric_at_sunfla.East.Sun.COM> CC: multihulls_at_ronin.com Eric Carsted Sun Microsystems - Orlando wrote: > > > > Cheap > > ----- > > you - Good luck, "Fast and cheap can be somewhat exclusive" > > > > me - Well, I guess I had that coming. Lets say my budget is in the 200 - 250K > > range. Along with other variables, cost is very closely related to _weight_; hence my belief that the cheapest boat will be the lightest boat for any given length. That turns out to be the Pacific proa. At the size we are talking about, the accommodation would be equivalent to a 47' catamaran. And my own cost estimates so far are exactly in the range you mention: $200 - 250K for a seven ton boat. I seriously doubt you can build a substantially heavier boat (60+' catamaran, 14 tons?) for that amount. > > As to the software, I have tried a couple that I found on the Internet, and > > basically I don't find them usefull. The Multisurf software from AeroHydro is _extremely_ useful for surface modeling and boats in particular. Perhaps you didn't give it enough time. The "durable joins" that characterize Dr. Letcher's "Relational Geometry" approach is unique and very desireable. http://www.netins.net/showcase/aerohydr/ It also is _essential_ to have the documentation for this program; then it becomes easy. > > Many of you seem to think it is going to take 5 years to build this sucker. To > > all of you I reply, I want it the water by Christmas 97. The interior wont be > > finnished, but I WILL be sailing! YEEEEHAAAAA!!!! Anyone care to lay odds? Yeah, I'll bet 10:1 you don't make it by then! Building and launching a large boat in a single year is a reasonable goal but you only have ten months left and haven't got your design done yet!!! I love to see and hear about large multihulls and wish you all the best; I just have a feeling that Christmas '97 is optimistic. Did you check out Jim Antrim's 55' catamaran? http://www.JosephOster.com/antrim/cat55.html Cheers, Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: Proa rudder-free? From: Joseph Oster <oster_at_wingo.com> Date: Wed, 12 Feb 1997 07:20:11 -0800 To: RJBole_at_aol.com CC: multihulls_at_ronin.com RJBole_at_aol.com wrote: > > > > Craig O'Donnell writes: > > > > << can you see any real reason a 20' proa shouldn't be steered by adjusting > > the raising and lowering of two center (dagger, lee) boards? >> > > > > I have had similar thoughts. Can an expert out there please clarify how much > > of the rudder's steering force is attributed to drag and how much is lift? Ideally, if the rig and centerboard are balanced correctly, _ALL_ steering force is lift, not drag... Craig's proposal has to do (I think) with moving the center of lateral resistance (the dagger boards) relative to the center of effort of the sails. Essentially inducing weather helm or lee helm to steer the boat, similar to the way a wind surfer is steered (except in the latter case it is the sail that moves fore and aft instead of the "dagger board"). The idea is sound, it's the mechanics and convenience that determine whether or not a particular implementation is viable. And have you seen the "Bruce foil" steering system used on Michael Schacht's 26' proa? He moves a pivoted foil/daggerboard fore and aft to accomplish the same thing. A picture and description can be found here: http://www.pacificproa.com/schacht/ > > One more query, about the rudder on tris: Might it be possible to lessen > > drag and increase steering ability by removing the large center rudder and > > replacing it with small rudders on the amas (assuming that it doesn't fly too > > high)? It seems that outboard rudders would have more of a lever arm, > > resulting in the same turning force but causing less drag. I am doing this very thing now on a 24' Crowther Bucaneer trimaran but not for the reason you mention. It is the dagger board that keeps the boat on track and the rudder ideally is neutral for minimum drag. Placing rudders on the ama doesn't (particularly) increase any lever arm, it just ensures that the leeward rudder will be buried and effective while a rudder on the main hull can lift out in certain conditions and be momentarily useless. The rudder on the windward ama that is high out of the water is virtually useless (until you tack!). Joseph -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: Racing Proas. From: Joseph Oster <oster_at_wingo.com> Date: Mon, 10 Mar 1997 16:11:09 -0800 To: Tony Hammer <ahammer_at_MNSi.Net> CC: multihulls_at_ronin.com Tony Hammer wrote: > > > > Between Lake Huron and Lake Erie! > > > > Detroit etc. Oh! Then I guess your $1,000 bet against proas will be safe from the threat of Russ Brown's Kauri... Too bad! :) Joseph -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: Stars & Stripes, Double Bullet II From: Joseph Oster <oster_at_wingo.com> Date: Mon, 10 Mar 1997 18:49:15 -0800 To: Frenette <dan.frenette_at_West.Sun.COM> CC: multihulls_at_ronin.com Frenette wrote: > > > > I haven't gone out on Double Bullet II for a while. Does it still move > > like a furnature boat with the new mast? When we _delivered_ (not raced) the boat back from Hawaii, we had a reef in all the time and still rarely went below 20 knots. Often we were blazing along at an easy 27 knots! During the race, I understand they broke one of the daggerboards while coming off a wave at 33 knots!!! Seventy-five feet makes for a very pleasant motion at sea, even in _BIG_ seas such as the 18 foot troughs we encountered approaching the Santa Barbara coastline. After pleasant conditions the whole trip, we had these huge seas and 32 knots of wind. I did one 11 hour shift on the helm during that period. Bob Hanel tells me he has fixed the steering problem that plagued the boat that summer and it feels altogether different; light and easy to steer now. > > When S&S came to ORCA they opened up the hulls so they could put sleeping > > area's in them. That is both of boats. Basicly a 60' boat is going to > > have a bit of room in them even if it's just a day sailor. In DB2, accommodations are _VERY_ tight and minimal. In the main compartments aft, two people sleep end-to-end on one long bunk! Another bunk forward of the hatch is reached by crawling through the _minimal_ galley (starboard) or nav station (port). The worst part was the noise when it was even a little rough. The crossarm tubes (3' thick, 6' fore/aft) _GROAN_ in their sockets and make a terribly loud banging noise. Very bothersome. Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: [MHml] Sci-fi proa! From: Joseph Oster <oster_at_wingo.com> Date: Tue, 20 May 1997 11:38:08 -0700 To: Norman Wagner <nwagner_at_kitimat.sno.net> CC: "Michael W. Schacht" <Mshot1_at_acmenet.com>, Multihulls <multihulls_at_ronin.com> Norman Wagner wrote: > > > > resupplying from land ,like kerosene lamps and propane stoves. Not to get > > into survivalist mode but the lamp can be replaced with 12v lighting that > > runs from solar and wind power but cooking??? Electric stove, oven, hot water heater... With enough(?) wind power, such systems could work, though more likely on a mooring than while sailing. Now how many amp-hours does it take to cook a meal? Instant hot water is a great feature, gas or electric, and if boiling hot, gets you virtually instant preparation of many "just-add-water" meals and drinks (coffee, tea, chocolate). A two-stage hot water system seems best; "warm" for washing, bathing, cabin heating, and "hot" which boosts the warm temp up to boiling at a galley faucet for food prep. Much material on this is available from land-based research and experiments that have had the same goal for decades: energy-independence! Cheers, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] C'mon... who designs proas? From: Joseph Oster <oster_at_wingo.com> Date: Wed, 06 Aug 1997 14:57:20 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_ronin.com Craig O'Donnell wrote: > > Who's doing that big one for Joseph Oster? I am!!! Jim Antrim has done alot of analysis and engineering and contributed substantially to the hull shape, rig, and choice of fulltime counter-rotating rudders fore-and-aft, etc. However, the size, weight, overall proportions, interior, deck layout, choice of single stayed aeroRig-style boom-sprit, and 3D CAD effort are all mine. I hope you won't drop me from your list! I am about to update the site with more persuasive arguments for why one would want to spend money on a large modern proa... Looking forward to your updated page, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Proas (again??), was Re: Robin's Folly From: Joseph Oster <oster_at_wingo.com> Date: Mon, 25 Aug 1997 07:14:26 -0700 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_ronin.com Very well stated on all points Dave! An important error however... Dave Culp wrote: > > turn turtle; almost certainly the cause of the loss of both Cheers and Godiva > > Choclateer). CHEERS was NOT lost at sea! Last I heard, she is in a museum in Exeter, England. > > (Certainly, the timetable of The Race doesn't allow for either the > > development work, nor racing experience necessary, but this *type* of race > > is right for a big proa) I don't know about this... Jim Antrim and I have done alot of theoretical work on Pacific proas and have a pretty complete set of algorithms for a scalable design based on the 21 meter cruising version. The boat could be completed by January or June of 1999 and have plenty of time for sea trials! They make so dang much sense! The only valid argument against them is ungainly length (and beam) relative to accommodation which, conversely, is exactly what makes them such superior oceangoing vessels for their _weight_! It is a concern only for crowded marinas and otherwise did not deter the old proa designers from creating the biggest possible boat from the least amount of materials. Cheers! Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: [MHml] Re: proa photos! From: Joseph Oster <oster_at_wingo.com> Date: Wed, 27 Aug 1997 13:51:54 -0700 To: MHml <multihulls_at_ronin.com>, David Bolduc <boldav_at_theonramp.net> Dave Bolduc has sent a second photo of JZerro showing the _COOL_ deck and "house" along with a better photo of it on the hard: http://wingo.com/proa/brown/ He also sent a photo and a line drawing of CHEERS (from Nautical Quarterly) which I have added to this page: http://wingo.com/proa/proanewi.html Thanks again Dave! Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Re: Cheers wins OSTAR (not) From: Joseph Oster <oster_at_wingo.com> Date: Mon, 01 Sep 1997 09:57:24 -0700 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_ronin.com Dave Culp wrote: > > Or, again, are *Newick* boats simply faster? Well this much _IS_ a given!!! CHEERS was probably the longest possible boat for the least amount of materials. And Dick Newick put it together with deep respect and understanding of the sea. How I long for the Moxie's routine grace and power... Looking out over S.F. Bay from Yellow Bluff, I often imagine Moxie charging comfortably along past Alcatraz at 18..20 knots with full party crew in stiff breezes like those she was designed for, heading for the Farallones and beyond with confidence. Long, light, _STRONG_, and right for the sea... Bigger boats are better boats... Lighter boats are cheaper boats... Bigger (better), Lighter (cheaper) boats are proas! Cheers, Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: [MHml] 26-28' kite-proa, steering linkage From: Joseph Oster <oster_at_wingo.com> Date: Wed, 03 Sep 1997 12:26:09 -0700 To: Dave Culp <dave_at_dcss.org> CC: Jim Antrim <antrimna_at_hotcoco.infi.net>, MHml <multihulls_at_ronin.com> Dave Culp wrote: > > Had some fun, too. Got a good look at Lakota, on Friday while she was in > > Santa Cruz, then was invited for a sail in Beauwolf V today (Alan > > O'Driscoll's "D"-Class cat. Hot stuff). I had to turn Alan down! > > (business meeting; we *may* get funding to build a 26-28' kite-proa, and > > a slip in Santa Cruz). Heady stuff, and a *great* holiday. Let me guess... Tim O'Neil? Tell us more! Please? Boat displacement? Kite sail area? BTW, I noticed an interesting diagram on the DynaYacht web site (http://www.dynayacht.com) that shows great details of the steering linkage for their dual rudder system (with canting ballast in between): http://www.dynayacht.com/mech%20plan.gif Of course, the proa's requirement of using opposite ends of the boat as bow and continuous rotation of the rudders adds more than just a "wrinkle"... Still, there are some valuable details for big boats there in this pioneering work. regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Wind Surfer Speed From: Joseph Oster <oster_at_wingo.com> Date: Tue, 09 Sep 1997 19:44:01 -0700 To: martin.hildebrand_at_vtt.fi CC: multihulls_at_ronin.com martin.hildebrand_at_vtt.fi wrote: > > Could it be possible to engineer a simple solution for that? How about as > > with a self tacking jib, attach a 'traveller' below the mast step and let > > it glide on a curved track. No adjustable shrouds needed. The wind pressure > > would automatically push the maststep to leeward, how much would be easily > > adjustable as with a traveller? This is _exactly_ the way Dick Newick's 1988 Ocean Surfer worked! The traveler was on the forward crossarm which was curved to follow the arc of the mast base as it pivoted at the hounds (the attachment point up the mast for the headstay and two shrouds). There is a DANGER though! If the base of the mast swings out too far and approaches the diagonal line between the headstay and shroud bases, all support is lost and the mast will fall down! I have a wonderful bunch of photos somewhere of this speedster and even some great video... Will post them when I find them. Robert Campbell mentioned a dinghy ("Skate"?) with a similar feature that I haven't seen... The most impressive dinghy sailing I _EVER_ saw was Russ Brown in front of his father's house in one he made himself with a mast that leaned to either side with the tug of a "string". WOW, that guy can sail!!! regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Mail failure From: Adminstrator <postmast{MHS:POSTMASTER_at_MSGATE}_at_dalat2.po.my> Date: Wed, 10 Sep 97 15:13:00 -0500 To: Joseph Oster <oster_at_wingo.com> DATE: 09-08-97 TIME: 11:01 FROM: MHS:oster_at_JARING (Joseph Oster) <oster_at_wingo.com> TO: MHS:tweyand_at_JARING (Tom Weyand) <tweyand_at_pmet-inc.com> CC: MHS:multihul_at_JARING (multihulls_at_ronin.com) <multihulls_at_ronin.com> SUBJECT: Re: [MHml] Fwd: non skid PRIORITY: Tom Weyand wrote: > > Subject: non skid The best results I have seen on other boats and experienced myself came from sprinkling liberal amounts of AwlGrip non-skid particles directly onto a fresh coat of polyurathane paint (_NOT_ MIXING IN THE PAINT prior to application!). The dry particles absorb the paint and excess particles simply blow away, leaving a superb and even non-skid finish. Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Mail failure From: Adminstrator <postmast{MHS:POSTMASTER_at_MSGATE}_at_dalat2.po.my> Date: Wed, 10 Sep 97 15:14:00 -0500 To: Joseph Oster <oster_at_wingo.com> DATE: 09-08-97 TIME: 14:39 FROM: MHS:oster_at_JARING (Joseph Oster) <oster_at_wingo.com> TO: MHS:djeffery_at_JARING <djeffery_at_dc.infi.net> CC: MHS:multihul_at_JARING (MHml) <multihulls_at_ronin.com> SUBJECT: Re: [MHml] Fwd: non skid PRIORITY: David Jeffery wrote: > > Why polyurethane paint in the non-stick application? Would enamel or > > even semi-gloss paint work well enough where you don't want any > > reflectivity from the surface? I personally have never considered anything but polyurathane for finishing boats as it is tough, hard, and holds up extremely well for years in the marine environment. _Especially_ for non-skid, hardness is quite important because otherwise (I would think...) the particles will wear away more quickly and reduce the effectiveness of the surface. Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Mail failure From: Adminstrator <postmast{MHS:POSTMASTER_at_MSGATE}_at_dalat2.po.my> Date: Wed, 10 Sep 97 15:15:00 -0500 To: Joseph Oster <oster_at_wingo.com> DATE: 09-08-97 TIME: 15:42 FROM: MHS:oster_at_JARING (Joseph Oster) <oster_at_wingo.com> TO: MHS:djeffery_at_JARING <djeffery_at_dc.infi.net> MHS:multihul_at_JARING (MHml) <multihulls_at_ronin.com> SUBJECT: Re: [MHml] Fwd: non skid PRIORITY: > > David Jeffery wrote: > > >> > > Why polyurethane paint in the non-[skid] application? Would enamel or >> > > even semi-gloss paint work well enough where you don't want any >> > > reflectivity from the surface? P.S. Surface reflectivity can be eliminated by adding the recommended "flattening agent" to the paint. I used Interlux on all my decks; one small can of "flattening agent" (I forget what they call it) added to each can of paint. It _IS_ expensive; as I recall, the price went from $17 to $25 per can with only a small increase in volume due to the flattening agent. Works _GREAT_ though. And be sure to buy extra cans of the AwlGrip non-skid particles; you can usually take them back un-opened but it's a big pain to run out or use too little. Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: Mail failure From: Adminstrator <postmast{MHS:POSTMASTER_at_MSGATE}_at_dalat2.po.my> Date: Wed, 10 Sep 97 15:24:00 -0500 To: Joseph Oster <oster_at_wingo.com> DATE: 09-09-97 TIME: 11:27 FROM: MHS:oster_at_JARING (Joseph Oster) <oster_at_wingo.com> TO: MHS:arthur_at_JARING (Alex. Arthur) <arthur_at_abdn.ac.uk> CC: MHS:multihul_at_JARING <multihulls_at_ronin.com> SUBJECT: Re: [MHml] A-Frame Rigs PRIORITY: Alex. Arthur wrote: > > Does anyone know anything about a-frame rigs, especially on cats? Not sure what you mean by "a-frame rigs" but if you are refering to two masts that meet at the top(?), I have seen a video of such a rig on a catamaran that supports a triangular main sail. It was a wild control system that used either edge of the main sail alternately as the leading edge! Very weird, somewhat like an AeroRig in terms of balance. I don't remember the old man's name though can find it if you like. I thought it looked far too complicated and heavy to be effective. regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Mail failure From: Adminstrator <postmast{MHS:POSTMASTER_at_MSGATE}_at_dalat2.po.my> Date: Wed, 10 Sep 97 15:27:00 -0500 To: Joseph Oster <oster_at_wingo.com> DATE: 09-09-97 TIME: 19:43 FROM: MHS:oster_at_JARING (Joseph Oster) <oster_at_wingo.com> TO: MHS:rlechner_at_JARING (Bob Lechner) <rlechner_at_erols.com> CC: MHS:duff_at_JARING (duff) <duff_at_island.net> MHS:multihul_at_JARING <multihulls_at_ronin.com> SUBJECT: [MHml] discussion of the principles PRIORITY: Bob Lechner wrote: > > Could we please have some discussion of the principles that go into > > designing a new generation multihull. For example, how does one determine > > the safe reaching speed of a catamaran as a function of wave speed and > > height? How does safe speed depend upon the vessels weight, hull volume, > > and length? > > > > Has any literature of technical substance been published addressing this > > subject? I composed a lengthy reply to these questions at the time you asked them and then managed to crash Netscape before sending it! Argghh! The essence of it was that these questions are being answered in the offices of leading naval architects around the world and they are not always eager to share their methods! Sailing magazines such as Seahorse (http://www.seahorse.co.uk/) and technical papers submitted to SNAME (Society of Naval Architects and Marine Engineers at http://sname.dt.navy.mil/) can be excellent and current. Usually safe speed is limited by righting moment and the tendency to bury the leeward bow. These forces can be computed along with hull drag to give some pretty good performance estimates but can be VERY complicated due to the wide range of conditions and sail configurations for any given boat. While alot of science and engineering is involved, it is very much an art of compromise. My simplistic outlook is that a bigger boat (of similar character) is _ALWAYS_ safer and faster than a smaller one. The ocean is HUGE; even Moxie at 50' can feel very small in a Gulf Stream gale! regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] discussion of the principles From: Joseph Oster <oster_at_wingo.com> Date: Thu, 11 Sep 1997 09:28:30 -0700 To: Bob Lechner <rlechner_at_erols.com> CC: multihulls_at_ronin.com Bob Lechner wrote: > > I really wasn't looking for the complicated part just a basic understanding > > of the mechanisms at play. For example, how does position of CG and CB, > > weight, length, and boat speed affect tendance to pitchpole.\ There are some fine books available that provide excellent insight into these issues. Chris White's book ("The Cruising Multihull") comes to mind (http://www.paw.com/Sail/neilpryde/newslet/17/17-cw.htm is an interview with Chris White). I also recall enjoying "Multihulls for Cruising and Racing" by Derek Harvey. A list of these and other multihull books can be found here: http://www.catsailor.com/ram_press.html though the page is hard to read!). > > I'd be happy with a relationship such as pitchpole velocity varies directly > > with length to some power. Would that be giving away the farm? Sounds way too simple to me! Don't get me wrong, I'm not trying to hide anything. The basics you refer to in your first paragraph are widely discussed and understood. It's the details and specifics of each boat that must be carefully analyzed because so many factors are at work including sea state. > > It kind of make you wonder though whether those proa proponents aren't right. Of course we are! :-) > > Maybe all that is happening is that high tech stuctural materials > > are being applied to evolutionarily dead technology. I wouldn't call catamarans "dead technology" just because they have a different design focus than a proa. Good catamarans are great boats with lots of accommodation in about 2/3rds the length of an equivalent proa and have lots of practical advantages. In the boat design game, one quickly realizes that there is no one single perfect compromise... regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] discussion of the principles From: Joseph Oster <oster_at_wingo.com> Date: Thu, 11 Sep 1997 12:43:14 -0700 To: Bob Lechner <rlechner_at_erols.com> CC: MHml <multihulls_at_ronin.com> Bob Lechner wrote: > > Thanks for the reading suggestions. I have read both of those books but I > > haven't seen the interview with Chris White. Gee, I remember extensive written discussions of CG, CB, pitchpoling, etc., and thought for sure that both of these books covered it? It was a long time ago when I read them... > > the Norwood derived equation for hull resistance/weight which explains the > > resistance hump that multihulls experience as speed is increased I talked (once) with Joseph Norwood about proas and was dubious of some weird rig ideas (a motorized rotor?) and his preference for Atlantic vs. Pacific proas. I have not read his "Twenty-First Century Sailing Multihulls". Is his resistance equation accepted by other major designers? My understanding is that the increased surface area resulting from a fuller hull shape in the ends (increased prismatic coefficient) is only a drag (literally!) at _SLOW_ speeds and is relatively insignificant at higher speed. Also, keeping weight out of the bows is crucial. There are others here who know far more than I on these subjects so let me make a few comments and step back a little: > > If heeling moment is not at a premium as proa proponents have argued... Righting moment for a Pacific proa (ama to weather) _IS_ definitely at a premium. Off hand, I would say a catamaran has twice the righting moment of a Pacific proa of the same weight (which has only 25% of displacement to weather instead of 50% like a cat). The cat is 2/3rds the length with twice the righting moment!!! This explains why a cat is more likely to pitchpole than blow over sideways and why a proa is more resistant to pitchpoling than a cat (50% more waterline with the same sail area). > > since it might involve widening the stern and would certainly increase the > > moment of enertia. Maybe water ballast in the leeward hull could be used. > > The proa configuration could have a distinct advantage if such an > > application made sense based on knowledge of basic principles. But who > > knows if it does? I cannot see _ANY_ sense adding water ballast to a leeward hull, cat or proa, under any conditions!? And I know this discussion isn't primarily about [Pacific] proas but... Proas don't have sterns! regards, Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] discussion of the principles From: Joseph Oster <oster_at_wingo.com> Date: Fri, 12 Sep 1997 06:13:12 -0700 To: Bob Lechner <rlechner_at_erols.com> CC: MHml <multihulls_at_ronin.com> Bob Lechner wrote: > > > > If you will permit me, according to Norwood's equation, frictional > > drag/weight (important at high speed -- beyond the hump) Again, according to naval architects I know, frictional drag is more important at _LOW_ speed where it is the dominant factor. At high speed, wave induced drag due to poor hull shape (low prismatic coefficient) becomes the much bigger obstacle. > > A naval architect friend of mine who designs > > International Canoes has increased prismatic coefficient in his > > most recent design in an attempt to increase speed. My point exactly! Even though increased prismatic increases surface area and frictional drag, the net result is higher speed potential in strong wind! Joseph wrote: >> > >Off hand, I would say a catamaran has twice the righting moment of >> > >a Pacific proa of the same weight (which has only 25% of >> > >displacement to weather instead of 50% like a cat). The cat is >> > >2/3rds the length with twice the righting moment!!! This explains >> > >why a cat is more likely to pitchpole than blow over sideways and >> > >why a proa is more resistant to pitchpoling than a cat (50% more >> > >waterline with the same sail area). Bob Lechner wrote: > > I am afraid that you lost me here. Why are you comparing boats of > > different lengths? Because the only fair comparison of cats and proas must be based on identical weight! The catamaran will be 2/3rds the length of a Pacific proa of THE SAME WEIGHT. Or put another way, the Pacific proa will be 50% longer than a catamaran of the same weight. This makes the Pacific proa inherently more resistant to pitchpoling than a catamaran, even though it has less righting moment... Honestly, I didn't mean for this to turn into another proa discussion! Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] discussion of the principles From: Joseph Oster <oster_at_wingo.com> Date: Tue, 16 Sep 1997 20:38:46 -0700 To: Bob Lechner <rlechner_at_erols.com> CC: multihulls_at_ronin.com Bob Lechner wrote: > > > > First we have to clear up a misunderstanding about the effect of the > > prismatic characteristic, of hull shape on surface area. Increasing the > > prismatic coefficient, Cp, does not increase the surface area. Hmmmm... Not sure I understand your example of wedge shape vs. rectangle... Suppose instead you start with a sumberged hemisphere? By definition, this shape has the best possible surface-to-volume ratio, i.e., the least possible surface for any given volume (or displacement). Stretching that same volume into a rectangular shape (increasing Cp) will increase its surface area, right? Joseph -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] discussion of the principles From: Joseph Oster <oster_at_wingo.com> Date: Tue, 16 Sep 1997 22:30:41 -0700 To: Bob Lechner <rlechner_at_erols.com> CC: multihulls_at_ronin.com Bob Lechner wrote: > > First we have to clear up a misunderstanding about the effect of the > > prismatic characteristic, of hull shape on surface area. Increasing > > the > > prismatic coefficient, Cp, does not increase the surface area. Just to be perfectly clear on this point, the cross-sectional shape of the hull (wedge vs. box vs. semi-circle) is irrelevant here. The half submerged sphere (or submerged hemisphere) has a prismatic coefficient (Cp) that is some fraction(?) of the half cylinder of same radius and length equal to sphere diameter. Re-shaping this underwater volume in any way (i.e., stretching it to increase Cp) will result in increased surface-to-volume ratio. This is a fundamental difference in perception! My simple example (and experience with different hull shapes using CAD software) convinces me that increased Cp results in increased surface area. I now understand your example; I just don't accept your argument... We have been using Cp numbers in the range of .59 to .62, well below .7 or .8! regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Worrell 1000 Preparation From: Joseph Oster <oster_at_wingo.com> Date: Tue, 30 Sep 1997 14:29:10 -0700 To: Claas.vanderLinde_at_FIM.unisg.ch CC: multihulls_at_ronin.com Claas.vanderLinde_at_FIM.unisg.ch wrote: > > > > Hi, > > > > I just read Randy Smyth's story about this year's Worrell > > 1000 on the Sailing World's web page... > > o Rigged a slick internal spinnaker halyard that retains a > > waterproof mast in the inevitable event of a capsize. > > > > Does anybody know how exactly he did this? I can only speculate... Small diamter PVC tube(s) attached inside the mast and containing the halyard(s) to keep the bulk of the mast watertight? Aloha, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] Balanced proa rig From: Joseph Oster <oster_at_wingo.com> Date: Tue, 07 Oct 1997 08:53:49 -0700 To: "Torbj??Linderson" <torbjorn.linderson_at_nmi.se> CC: Alex Durrant <alex_at_bukitasam.co.id>, "'Matthieu Rougevin-Baville'" <roubav_at_hol.fr>, "'Multihulls Group'" <multihulls_at_ronin.com>, Jim Antrim <antrimna_at_hotcoco.infi.net> Torbj??Linderson wrote: > > > > at a balanced boom arrangment which is a hybrid of the Aerorig and a > > conventional one. I suppose this is a good time to introduce the balanced rig that Jim Antrim and I have come up with for our proa design. As you can imagine, such a rig is ideal for a proa which must otherwise have a jib at each end. I looked at the AeroRig but believe a much lighter structure rig can be obtained using a convetional stayed mast and this kind of "boom": http://www.pacificproa.com/rig.html Some details are left out... Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Anti-commercial for a spinnaker From: Joseph Oster <oster_at_wingo.com> Date: Tue, 14 Oct 1997 07:50:38 -0700 To: Robert Hepler <rhepler_at_kkz-cma.com> CC: List - Cruising <cruising_at_ronin.com>, List - Live-aboard <live-aboard_at_centaur.astro.utoronto.ca>, List - Multihulls <multihulls_at_ronin.com> Robert Hepler wrote: > > > > This may be a breach of netiquette, but I am having trouble finding a > > used spinnaker down here in PR. The cat I need it for is 33' LOA, 18' > > BOA, 40'mast (with masthead shrouds and sheaves), and about 6 tons > > displacement. > > > > Basically I am looking for a used, inexpensive 1.5oz (for the 20 > > knot tradewinds ;-) Is this heavy enough? ) spinnaker. > > > > Any ideas. Two big name folks here in the S.F. Bay area have their used sail inventory on-line. Mark Rudiger is navigator on the leading Whitbread boat "EF Language": http://www.sfsailing.com/leech_rudiger/newlife.html And Kame Richards is well-known here for all kinds of racing and cruising sails: http://www.sailmaker.com/usedsail.htm Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Atlantic 42 From: Joseph Oster <oster_at_wingo.com> Date: Wed, 15 Oct 1997 17:54:12 -0700 To: "Mr. Fish" <tvigmny_at_worldnet.att.net> CC: multihulls_at_ronin.com Mr. Fish wrote: > > idea what the atlantic 42 looks like. Does any one know who the dealer > > was. Perhaps he has a web site we can all look at the boat with. For purposes of discussion, I have created a page with some photos of an Atlantic 46 from Chris White's book "The Cruising Multihull": http://www.JosephOster.com/chriswhite/ > > Secondly placing the helm station in the middle. Seem like a terrible > > waste of space to me. Generally you are sitting at anchor or in a > > marina. to lose all that space because the helm station is in the > > middle seems silly to me. Space isn't lost, just re-arranged. As you can see on the above page, photos of the interior of an Atlantic 50 show lots of room in the hulls. > > As far as the helm station forward. For thousands of years boats have > > been steered from the stern. Certainly technology has come far enough > > to where if the optimum helm station was forward the helm would be there > > by now. It _IS_ forward on many ships... The aft section of many boats is usually the most comfortable in rough seas which is why the master's cabin is often placed there. Hull shape is a big factor of course but many designs rely on a relatively wide flat exit at the stern to reduce pitching. With long skinny hulls and bow-shaped sterns, my experience on the 76' catamaran Double Bullet II convinced me that the _CENTER_ of the boat at the base of the mast is by far the most stable position. DB2 has two helm stations at this position, one either side of the boat. It was very clear going forward _OR_ aft that while bow and stern are both going up and down, they are rotating about the middle which barely moved by comparison. Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] T-Shirts Seen at the Sailboat Show From: Joseph Oster <oster_at_wingo.com> Date: Fri, 17 Oct 1997 06:15:45 -0700 To: Tom Surles <Jane_Surles_at_compuserve.com> CC: Multihulls <multihulls_at_ronin.com> Tom Surles wrote: > > > > Two T-shirts worthy of note were seen at the Sailboat Show in Annapolis: > > > > "B-reak O-ut A-nother T-housand" This phrase was attributed to Bob Hanel, owner of Double Bullet II, who has alot of experience Breaking Out Another Thousand... In addition to damages suffered in the last Cabo Race he lost his rig in this year's TransPac; a 101 foot carbon wing mast with new mainsail!!! Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Re:speed (give your head a shake) From: Joseph Oster <oster_at_wingo.com> Date: Tue, 21 Oct 1997 11:34:57 -0700 To: duff <duff_at_island.net> CC: multihulls_at_ronin.com duff wrote: > > > > First off, I would be the first to use foils, IF it would work..... Dave Keiper proved in the late sixties and early seventies that foils on a cruising multihull _CAN_ work: http://www.igateway.net/~dakh/williwaw.html I have seen his video and nearly finished his book; both are _GREAT_! Given the advances in materials and understanding of multihulls that has occurred in the past twenty years, there is no question in my mind that narrow vision and lack of money are the only things keeping foils from being the next "big thing" in multihulls, even if it takes another twenty years. As to windsurfers, one of their most critical features in my mind is the dynamic control of the rig by the human body in response to wind gusts that allow them to be routinely "over-canvased" and sailed so hard. I can imagine the day when similar control of rigs on large multihulls will increase the performance potential for any given sail area. Are windsurfers sailboats? I don't think so but am not inclined to engage in the hair-splitting definitions that separate them from Sunfish/Sailfish. Kite boats (or skis) also are a clearly different category than boats with sails attached to spars. This is plainly obvious, isn't it Dave? Even more so than windsurfers, "apples and oranges" applies to kite boats, IMHO. I think they are wonderful creations with great potential and can be compared with sailboats on many criteria but they seem to me like the difference between internal combustion and fuel cells! Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Kite boats From: Joseph Oster <oster_at_wingo.com> Date: Thu, 23 Oct 1997 10:58:17 -0700 To: Dave Culp <dave_at_dcss.org> CC: MHml <multihulls_at_ronin.com> Joseph Oster wrote: > > > > Kite boats (or skis) also are a clearly different category than boats > > with sails attached to spars. This is plainly obvious, isn't it > > Dave? A private correspondant has persuasively brought my attention back to the virtues of the "junk rig"... In thinking again about modern versions (for a proa, of course!), I _ALMOST_ found myself apologizing to you for my own limited vision in the above comment because I can easily see the similarity of "flying" a junk rig like a kite on short strings! However, I saved myself this embarrasment ;-) by deciding that it's only a kite (vs. "conventional sail") if it can be "flown" at speeds different than the boat itself as would be the case with Flexifoils, for example. A more subtle distinction... Cheers, Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Tiny Dancer From: Joseph Oster <oster_at_wingo.com> Date: Wed, 12 Nov 1997 07:09:34 -0800 To: Dave Culp <dave_at_dcss.org> CC: MHml <multihulls_at_ronin.com> Dave Culp wrote: > > >> > >4) Go to water ballast - increases the weight and structure. > > > > Never, *never* add mass to improve the performance of any sailcraft (not > > including half-boats, or attempts to improve existing vessels). Better to > > maximize the mass you must carry. Stirring up this debate again?! OK, I'll take the bait... According to my archives, we covered water ballast heavily on this list from March thru May of '96 and made converts among some who initially didn't believe it makes any sense. Never say never Dave! Once you "maximize the mass you must carry" using the Pacific proa configuration, I believe the reason water ballast works so well for W60s must also apply to proas. I know about the need for stronger connecting structures... A 100(?!) pound boat plus 160 pound crew, Tiny Dancer is carrying around 77% of total displacement to weather!!! This will _NEVER_ "scale up" to "yacht" size as a Pacific proa, though it is what I might expect of an Atlantic proa. The figures I have been working with for large offshore Pacific proas use only 25% total displacement to weather. At the expense of increasing total displacement by only 12.5% (half the ama's displacement, water ballast will increase righting moment by 50% (ama weight times 1.5). In heavy air, this _MUST_ result in the ability to push the boat harder and faster, just as it does with monohulls. > > 5) (unmentioned) --Go to Joe Norwood's version of a "modified" pacific > > proa; carry all boards and rig on the leeward hull; all accomodation in the > > windward (hulls of quite differing L/B ratios, to account for the high > > displacement of the "ama" at rest). This sounds much more like a modified _Atlantic_ proa to me. regards, Joseph -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] water ballast and proas From: Joseph Oster <oster_at_wingo.com> Date: Wed, 12 Nov 1997 12:15:31 -0800 To: "Dan Frenette [Service SE]" <dan.frenette_at_West.Sun.COM> CC: multihulls_at_ronin.com Joseph Oster wrote: > > >> > > A 100(?!) pound boat plus 160 pound crew, Tiny Dancer is carrying >> > > around 77% of total displacement to weather!!! This will _NEVER_ >> > > "scale up" to "yacht" size as a Pacific proa, though it is what I >> > > might expect of an Atlantic proa. Then Dan Frenette replied: > > > > Don't know about that, carbon fiber, arimid honeycomb isn't the end > > all. At some point down the road someone will develop a stronger > > subtance and we may get low density foams that will allow use to scale > > this up to a much larger size. What I meant was that a large Pacific proa will _NEVER_ have 77% of total displacement to weather. It really defies the definition of Pacific proa and is only possible on Tiny Dancer because of the huge proportion of displacement (160%!) provided by crew weight. For offshore cruising or racing, crew weight is a much smaller fraction of the total. For those who haven't heard all this before, the catamaran and Atlantic proa have very much in common: hulls of equal length and similar displacement, connectives that must bear the full weight of the boat. Both are different in the same ways from the Pacific proa which has a small hull to weather (1/2 length and 1/3rd displacement of main hull) and much less stress on the connectives (25% displacement is being lifted instead of 50% or more and drag of the weather hull is reduced to zero when routinely flying that hull). > > The thing that I see here is measurments on side to side but when you > > compair mono's to multis the mono has a net increase in side to side > > relitive to end to end stiffness than a multi. When we go about as > > wide as you are long in a cat for example the critical problem is > > going to be pitching motion. I understand the last part but not "mono has a net increase..." The Pacific proa with only 25% displacement to weather is far more resistant to pitchpoling than cats or Atlantic proas. Or put another way, they will tip over to leeward long before they will pitchpole. The small amount of water ballast required to achieve big increases in righting moment (on a Pacific proa) will not distort the "stability footprint" enough to induce pitchpoling. As to shifting water ballast in the weather hull, this can easily be prevented with bulkheads, baffles, etc. Ideally, a water ballast tank in each end allows the water to be pumped (and kept) aft. > > If you add weight you add drag and at high speeds drag will decrease > > your top end speeds in all but a few special cases. Same applies to Whitbread 60s but water ballast still works for them to carry more sail in heavy weather and go faster! For those who don't understand the fuss about proas, the bottom line for me is that Pacific proas carry _less_ than half of total displacement to weather. This results in specific advantages that are lost when both hulls are the same size. The primary advantage can be stated as follows: longest possible waterline for any given weight (and cost!) To me, if half or more displacement is carried to weather you are talking about catamarans. "Atlantic proas" are catamarans with weight shifted to weather and the rig shifted to one hull from the middle. Dick Newick puts his Atlantic proa rigs on the weather hull and Norwood puts his on the leeward hull (which deserves another name I guess...). While both methods eliminate the mast compression load on the crossarm, they are otherwise similar to catamarans in many respects (except they have bows and rudders at both ends!). Cheers, Joseph -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Tiny Dancer Images in GIF From: Joseph Oster <oster_at_wingo.com> Date: Wed, 12 Nov 1997 15:36:51 -0800 To: Ted Warren <twarren_at_alum.mit.edu> CC: Multihulls Maillist <multihulls_at_ronin.com> Ted Warren wrote: > > > > The previous .jpg images have been converted to > > .gif and are much smaller in kilobytes(load faster). Hi Ted, In my experience, photographs saved as compressed .JPG will always have smaller file sizes then .GIFs. Using your original .JPG images, I finally took the time to whip up a web page for you: http://www.pacificproa.com/warren/ This page has thumbnails that link to larger images, all of which are considerably smaller in file size than what you have posted. I also applied some Photoshop tricks to make them more legible. regards, Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] water ballast and proas From: Joseph Oster <oster_at_wingo.com> Date: Thu, 13 Nov 1997 06:38:32 -0800 To: "Dan Frenette [Service SE]" <dan.frenette_at_West.Sun.COM> CC: multihulls_at_ronin.com Joseph wrote: > > >> > > The Pacific proa with only 25% displacement to weather is far more >> > > resistant to pitchpoling than cats or Atlantic proas. Or put another >> > > way, they will tip over to leeward long before they will pitchpole. And Dan replied: > > > > You lost me here. When you get this amount of leverage with the sail > > area to back it up pitchpoling will be a problem. No. The Pacific proa has less righting moment than a catamaran of the same weight but is about 64% longer on the waterline. The proa will be far more resistant to pitchpoling because it is much longer and yet uses roughly the same size rig as the catamaran of equal weight. For example, the 68' design on my proa page has a rig and total displacement nearly the same as the Venezia 42 catamaran. Pushing both to their limits, which one do you think will pitchpole first? Even using water ballast on the proa, it will still have only 33% displacement to weather compared to the catamaran's 50% (though the proa is slightly wider between the hulls... the leeward pod increases beam but doesn't add to stability until about thirty degrees of heel). > > Putting the mast on one hull on a cat would do the same thing without > > the complexity of dual rudders. Rudders are relitively costly to build, > > maintain, and weigh a bit in the ends of the boat. I agree it will do the same thing as an Atlantic proa... A Pacific proa, on the other hand, gains substantial waterline length with associated advantages for speed, seaworthiness, etc. Proas and cats both have two rudders so that's a push. Jim Antrim and I have located the proa rudders half-way between the middle and ends of the boat because in our design they are down all the time. Joseph P.S. I posted this Wednesday afternoon and it didn't make it to the list so am reposting now. Pardon me if two copies appear... -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Re: paralyzed sailors From: Joseph Oster <oster_at_wingo.com> Date: Fri, 14 Nov 1997 20:16:44 -0800 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_ronin.com Dave Culp wrote: > > > > It is possible to attach a self-actuated trim tab to the trailing edge of > > any rudder (even better if you suspend it on a short tailboom--like the > > Walker Wingsail). The "self-actuating" part involves a simple link, from a > > crank on the rudder skeg (or hull bottom, if a spade rudder), to a similar > > crank on the trim tab. <snip> > > I always thought this had limited appeal, only for self steereres (in the > > old days, when they produced little power), or really beastly boat-types > > (like traditional catboats), but reducing force on the tiller for a > > disadvantaged sailor is perfect. Interesting idea. When I did the Scanmar (Monitor) wind vane site I finally was able to thorougly understand and appreciate the way they multiply a small force (the wind vane) to steer large boats. There is a diagram here: http://www.selfsteer.com/monitor.html And if you grab the wind vane and move it directly you can steer the boat with very little direct effort. Photos and text on the following page show a conventional electronic tiller pilot connected to the wind vane to steer a magnetic course: http://www.selfsteer.com/geoffpack.html Sailors with disabilities may be able to adapt and utilize this approach for tiller steering with minimal effort. The Monitor is truely a wonderful piece of gear. Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] No motor From: Joseph Oster <oster_at_wingo.com> Date: Tue, 16 Dec 1997 15:46:08 -0800 To: Christopher/Laurel Taylor <ct-lst_at_rivnet.net> CC: multihulls_at_ronin.com Christopher/Laurel Taylor wrote: > > > > And that is exactly what sail propulsion is (without a reverse gear yet!). Proas _DO_ have a "reverse gear" under sail! And the added manuverability in close quarters can be simply amazing to see. Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Proa at Hamburg Show From: Joseph Oster <oster_at_wingo.com> Date: Tue, 23 Dec 1997 09:54:08 -0800 To: Marty Rieck <scsrieck_at_csd.uwm.edu> CC: Dave Culp <dave_at_dcss.org>, multihulls_at_ronin.com Marty Rieck wrote: > > > > I recently returned from the Hamburg Boat Show and had a chance to meet > > Dr. Peter Wittkopf and to see his proa, which he calls the Deltro. Hi Marty, I received the three photos you sent last week and finally created a web page to show them: http://wingo.com/proa/deltro/ I included the text of your note as additional description. If you or anyone else has other details to add, please bring it to my attention and I will update the page. regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Proas: Hobby-horsing From: Joseph Oster <oster_at_wingo.com> Date: Mon, 29 Dec 1997 07:34:11 -0800 To: rsr8429_at_ix.netcom.com CC: multihulls_at_ronin.com rsr8429_at_ix.netcom.com wrote: > > > > Hi Proa nauts, Since proas have symetrical ends, are they prone to > > excesive pitching (hobby-horsing), like some of the older style cats? Without the broad flat exit at the stern typical of modern boats, the double-ended proa can indeed produce a hobby-horsing motion if the bows are not full enough. IMHO, the answer is twofold: 1) keep the prismatic coefficeint comparitively high: 0.6 or so, and 2) use a high length-to-beam ratio (like 17:1) which also happens to be great for speed! regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Proas: Hobby-horsing From: Joseph Oster <oster_at_wingo.com> Date: Mon, 29 Dec 1997 11:44:45 -0800 To: Lee Vogtman <lvogtman_at_fred.net> CC: multihulls_at_ronin.com Lee Vogtman wrote: > > > > Joe, excuse my ignorance here -esp of proas- but with a ratio of 17:1 > > you could have a 34' craft with a 2' beam. Am I following this > > correctly? Waterline beam, yes! 3' waterline beam for 51' LOA (like Moxie!), 4' for 68' LOA, etc. I believe this ratio (or higher!) is common on major racing multihulls. While waterline beam is not usually published for cruising cats, a ratio of 10:1 is more typical for this type of craft... Joseph -- http://www.JosephOster.com (415) xyz-1234
Subject: [MHml] Re: Fish Fins/ was planform of daggerboards etc. From: Joseph Oster <oster_at_wingo.com> Date: Fri, 23 Jan 1998 10:32:02 -0800 To: Jesse Deupree <jdeupree_at_mail.biddeford.com> CC: multihulls_at_steamradio.com Jesse Deupree wrote: > > > > An article in Scientific American last year (don't have the month- a > > picture was on the cover) explored this issue- showing a mechanical tail > > that duplicated tuna motions and produced drive at a dramatic efficiency > > improvement over a propeller. Here are some web pages on it: http://web.mit.edu/towtank/www/tuna/ http://popularmechanics.com/popmech/sci/tech/9501TURBPM.html http://the-tech.mit.edu/V115/N49/robotuna.49n.html http://w3.mit.edu/afs/athena/org/t/towtank/www/tuna/pictures.html regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] hull shape From: Joseph Oster <oster_at_wingo.com> Date: Fri, 23 Jan 1998 11:32:24 -0800 To: Gary Dierking <garyd_at_wave.co.nz> CC: Multihulls mailing list <multihulls_at_steamradio.com> Gary Dierking wrote: > > > > Sounds like it's time to talk about planing floats on trimarans. I know > > it's been tryed at various times but I've had no first hand experience > > with it. Newick had some dynamic lift built into some of his. The > > first thing you always hear is that they'll pound and be noisy etc, but > > I don't think that's an issue if you're just trying to go fast. > > Any first hand experience out there? I've had only one sail on Aotea, unfortunately in very little wind. In those conditions, the swells caused _TERRIBLE_ banging on the weather float, shaking the whole boat. At speed, as you say, it isn't a problem. I've also sailed more on Erin with similar shaped floats and not noticed any problems... http://www.antrimdesign.com/aotea---40-trimaran.html http://www.antrimdesign.com/antrim-30-trimaran-erin.html Aloha, Joseph -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Spinnaker trim on cruising cats? From: Joseph Oster <oster_at_wingo.com> Date: Fri, 23 Jan 1998 15:09:36 -0800 To: KJenk2 <KJenk2_at_aol.com> CC: multihulls_at_steamradio.com KJenk2 wrote: > > > > Is there another way to > > handle symmetrical chutes on a cat without using a pole? I think the method we used on the 50' trimaran Moxie would work fine. Each clew of the spinnaker has both a guy lead to the respective bow and a sheet leading aft to a fairlead near the stern. The entire spinnaker could easily be jybed from the cockpit; there was no need for a pole! Perhaps this is the same as what you are describing? Variations on this theme might include: 1) A "twinger" on each side to pull the sheets down, effectively moving the sheet leads forward and 2) On trimarans, another guy going to the bow to allow the spinnaker to work in reaching conditions like an asymetric. Can I go sailing with you in Santa Cruz? :-) regards, Joseph Oster (Sausalito, CA) -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] A-cat site From: Joseph Oster <oster_at_wingo.com> Date: Tue, 03 Feb 1998 10:30:37 -0800 To: "Torbj??Linderson" <torbjorn.linderson_at_nmi.se> CC: "Stefan T??lom" <stefan.tornblom_at_lidingo.mail.telia.com>, "Multihulls_at_Steamradio. Com" <multihulls_at_steamradio.com> Torbj??Linderson wrote: > > > > Interresting A-cat site: > > > > http://traviata.bo.cnr.it/~fischer/sailing/mikan/pictures.html I noticed an interesting observation in the first paragraph regarding hull shape aft that could also apply to (double-ended) proas: "The second reason for this shape is a more favourable pressure distribution. Each catamaran produces high pressure in the stern region, and thus dynamical lift. This undesirable lift puts more pressure on the bows, and thus increases the danger to pitchpole. Due to the concave lines in the stern region this unfavourable effect is reduced. Thus the boat requires less volume in the bow region which has a positive impact on the wave drag and on the upwind performance." Funny how modern science supports ancient wisdom, eh? Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Lift From: Joseph Oster <oster_at_wingo.com> Date: Wed, 18 Feb 1998 17:19:23 -0800 To: Bob Lechner <rlechner_at_erols.com> CC: multihulls_at_steamradio.com Bob Lechner wrote: > > > > I doubt anyone but you and I have read this far. Probably true... _WAY_ too verbose for me! I conceed Dave's point that the halyard pulling near horizontal at the masthead has a long lever arm to push the bow down... On the other hand, I have had that same "feeling" that flying an asymetric spinnaker doesn't push the bow down as hard as other headsails... Aren't there any sailmakers in this group who actually know? Cheers, Joseph Oster -- http://www.pacificproa.com/ http://www.JosephOster.com/sailing/myboat2.jpg http://www.JosephOster.com/sailing/myboat-cyc.jpg (415) xyz-1234
Subject: Re: [MHml] Re: The "Lift" debate From: Joseph Oster <oster_at_wingo.com> Date: Mon, 23 Feb 1998 08:39:15 -0800 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_steamradio.com Dave Culp wrote: > > > > Joseph Oster: >> > >OK, now I'm insulted! Less coffee and more sleep for you Dave. Tom >> > >has a point; perhaps you need more experience on "real" boats... > > > > Wasn't too much coffee, but too little wine. Working on that... I fail to > > see how "experience" affects the underlying physics of sailing; All I'm saying Dave is that talking about physics and dismissing a wide-spread perception among highly qualified sailors (now including Randy Smyth!) with your remark that "The earth 'seems' to be flat, and the sun 'seems' to rotate around us" is not convincing me. As to precisely what the sail shapes, limited conditions, and extent of "lift" are that we have percieved, I cannot say. I am simply unwilling to deny my own experience based on potentially incomplete physics. Your understanding of the math certainly exceeds my own. If you had these experiences yourself on boats like Tom's Triad or Antrim's Erin, I'm confident that you would find an explanation consistent with sailing physics. > > I will grant you that I have little "racing" experience--never saw the > > point. Why not just build a faster boat and "horizon" the fleet? Never > > had all that much patience for "rules" either. Sorry. I totally agree! Cheers, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Tacking proas From: Joseph Oster <oster_at_wingo.com> Date: Sun, 22 Mar 1998 11:17:32 -0800 To: "ARNOLD jj J LANDE'8149" <alande1_at_juno.com> CC: multihulls_at_steamradio.com, "Ava M. Burgess" <multimag_at_aol.com> ARNOLD jj J LANDE'8149 wrote: > > > > The recent thread has (perhaps charitably) ignored my article on page 45 > > of the current MM entitled "Tacking Proa". I am surprised your article got past the Multihull Magazine editor as it seems to have little or nothing to do with proas, IMHO... Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Russ' Proa Described From: Joseph Oster <oster_at_wingo.com> Date: Sun, 10 May 1998 08:23:05 -0700 To: batwing_at_kerrlake.com CC: multihulls_at_steamradio.com Mark Balogh wrote: > > > > Dave, > > > > Help me out if I am missing something on these pages but I only see the > > new Jzero. > > > > Mark I don't have photos of the original JZERO other than those in the Wooden Boat article; so at the risk of upsetting the good folks at WB Magazine, I scanned two photos and included them on the following page with your wonderful story of sailing the boat with Russell. http://www.pacificproa.com/brown/jzero78.html Thanks again for a classic tale of the sea! Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Brown's proa From: Joseph Oster <oster_at_wingo.com> Date: Tue, 12 May 1998 07:43:23 -0700 To: dnewick_at_gwi.net CC: multihulls_at_steamradio.com, Porter Thompson <waheguru_at_msn.com> Newick wrote: > > > > Russ Brown's first 37' proa is now for sale on Martha'a Vineyard at a > > reasonable price. Contact Dick Newick. Hello Dick! I was surprised (disappointed!!!) to read your note that Porter had decided (again) to sell Kauri (http://www.pacificproa.com/brown/). The last time I talked with him he had, much to my relief, taken it off the market and decided to keep it. I had long anticipated the season when Porter would finally decide to take Kauri south again for the winter (as Russell had done), a sailing adventure I looked forward to joining him on... He returned my phone call last night and confirmed that your information is more current than mine and that you have seen the boat recently; it has been three years since I last sailed Kauri with him. Apparently, since he hasn't lived on the Vineyard for years, he isn't able to use the boat nearly enough to make seasonal launchings, haulings, and maintenance worthwhile. I have encouraged him to join this list and tell us what he has learned in eight years of proa sailing. Best regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Hydro Prediction Software From: Joseph Oster <oster_at_wingo.com> Date: Thu, 28 May 1998 14:42:56 -0700 To: johnscott_at_panacom.com CC: multihulls_at_steamradio.com johnscott_at_panacom.com wrote: > > > > Does anyone know of any marine (or perhaps aircraft?) velocity > > prediction software that could handle all or part of a project like > > this? Have you looked at "SPLASH"? http://www.panix.com/~brosen/ I first saw this mentioned in a Seahorse article related to the monohull yacht "Morning Glory". Would love to see your results! Aloha, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] Russ Brown in Sausalito! From: Joseph Oster <oster_at_wingo.com> Date: Mon, 08 Jun 1998 15:38:42 -0700 To: MHml <multihulls_at_steamradio.com> Proa News! Russ Brown and his latest proa, JZERO, have just arrived in Sausalito, California (San Francisco area), from Cabo San Lucas. He will apparently be leaving the boat in this area for awhile and going back to work in the Port Townsend area. Boat looks great! I had only a little time to talk with him but plan to meet him again tommorrow. regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: [MHml] More JZERRO Photos... From: Joseph Oster <oster_at_wingo.com> Date: Tue, 16 Jun 1998 17:29:58 -0700 To: MHml <multihulls_at_steamradio.com> For your viewing pleasure - Some proa photos of JZERRO supplied by Russell Brown: http://www.pacificproa.com/brown/jzerrophotos.html I didn't take a camera aboard; he loaned me these for a day. The sail on Saturday under main alone was _FANTASTIC_!!! Enjoy, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Jzerro's daggerboard From: Joseph Oster <oster_at_wingo.com> Date: Wed, 17 Jun 1998 12:21:02 -0700 To: johnscott_at_panacom.com CC: multihulls_at_steamradio.com johnscott_at_panacom.com wrote: > > > > that the newest Jzerro had a large daggerboard in the log and > > wondered why. As info on Russ' boats is rather hard to come by, I > > don't know if this is the first proa of his with this arrangement. It is the third to my knowledge... As the photos show, Kauri, Cimba and the latest Jzerro all have this arrangement. One interesting result of placing it there is that the whole boat slips to leeward slightly when the ama rises and the daggerboard loses contact with the surface, causing the ama to drop down again... We didn't use the daggerboard or jibs when sailing last Saturday. Completely unnecessary for the course and conditions. We still easily passed all visible boats. regards, Joseph Oster http://www.pacificproa.com/brown/jzerrophotos.html -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Jzerro's water ballast From: Joseph Oster <oster_at_wingo.com> Date: Thu, 18 Jun 1998 08:22:23 -0700 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_steamradio.com Dave Culp wrote: > > > > I'd never want to under estimate Russ Brown. I would *love* to hear his > > reasoning for trying it, and his results. http://www.pacificproa.com/brown/jzerrophotos.html On another matter, Russ is _VERY_ enthusiastic about the use of water ballast in the ama under certain conditions. He has a large bilge pump in the cockpit with hoses to the ama that allow him to fill and drain a tank of 800 lbs. or so... BTW, it _IS_ interesting to note that all three of these boats had certain features in common including water ballast, ama daggerboard and retractable rudders (though the Kauri photos don't show the ama daggerboard clearly as I had thought). I believe Russ is interested in full-time counter-rotating rudders because he mentioned building them for a radio controlled model trimaran. Being retractable seems essential in either case. Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Jzerro's water ballast From: Joseph Oster <oster_at_wingo.com> Date: Fri, 19 Jun 1998 17:13:32 -0700 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_steamradio.com Dave Culp wrote: > > > > At 8:22 AM -0700 6/18/98, Joseph Oster wrote: >> > > >> > >http://www.pacificproa.com/brown/jzerrophotos.html >> > > >> > >On another matter, Russ is _VERY_ enthusiastic about the use of water >> > >ballast in the ama under certain conditions. > > I cannot resist a plug here. In the April, 1998 AYRS New England Group > > newsletter (not available onliine, not available to non-AYRS members--but > > you could *join*) there is an article by Henry Gilfillan on automatic > > water ballast for multihulls, including proas. Sounds great! Maybe enough for me to join!!! > > Retractable, counter-rotating rudders is a challenge. The clever system > > of building the rudder into a rotating "plug" with case might be a good > > approach. Though this cylinder approach sounds interesting (and we've discussed both these mthods before), I was thinking of the simpler case of retracting only when the rudders are aligned fore and aft. Basically a way to retrieve and repair them or retract them in a storm (or beach landing!). The rudders Russell uses are _light_ and simple! regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Trailerable cruising proa? From: Joseph Oster <oster_at_wingo.com> Date: Mon, 03 Aug 1998 13:06:46 -0700 To: Hans-Dieter Bader <hdbader_at_hotmail.com> CC: multihulls_at_steamradio.com Hans-Dieter Bader wrote: > > > > Isn't there a German proa around close to production finish, which would > > occupy exactly that market segment! Forgot the name, but was in the > > Multihull Magazine Proa special. Deltro - "The ultimate Beachsailor" by Dr. Peter Wittkopf http://www.pacificproa.com/deltro/ regards, Joseph Oster -- http://www.pacificproa.com/links.html (415) xyz-1234
Subject: Re: [MHml] PROAS From: Joseph Oster <oster_at_wingo.com> Date: Sat, 15 Aug 1998 21:57:19 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com Craig O'Donnell wrote: > > > > The current discussion might smack a little > > of excessive formalism, but there are many of us who feel the area of "hull > > and a half boats" needs a little clarification. NOBODY is an expert on 'em. Well Craig, some people are more expert than others! Dick Newick and Russ Brown are certainly at the top of the food chain in the proa department, IMHO. Some of your arguments sound quite lame in the face of Newick's innovation and experience; perhaps you need to read more about the original Cheers project 30+ years ago so you can recognize an expert when they are talking to you! While I prefer the "Pacific proa" configuration myself to the "Atlantic proa", Newick's statement that "My ... designs are usually recognized as proas because they are symmetrical about amidships and sail in either direction" speaks for itself as an obvious truth. And I'll never forget the old hand painted sign that used to hang in Dick Newick's shop on the Vineyard: "Beware: Proa Constructor" regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] EXPLORER arrives! From: Joseph Oster <oster_at_wingo.com> Date: Sun, 16 Aug 1998 22:27:36 -0700 To: MHml <multihulls_at_steamradio.com>, BAMA ml <bama_at_tango.rahul.net> Bruno Peyron, Skip Novak and crew on EXPLORER arrived under the Golden Gate Bridge today at 16:40:46 Pacific time. After dropping their chute they made some awesome speed runs in front of the S.F. skyline past the press boat (a 64' catamaran owned by Richard Spindler of Latitude38). They even flew a hull! (WOW!) Besides myself and the French and Japanese television crews on board, I had the pleasure of meeting our own Duff Sigurdson from the Ronin Project who came along with us on the press boat! A _GREAT_ time was had by all!!! A press conference was held at the Corinthian Yacht Club (http://cyc.org/map.html) where EXPLORER is on a mooring. The 86' catamaran will be moved next door to a dock at the San Francisco Yacht Club (marked as "Belvedere" on the above map) for viewing over the next two weeks, then will be de-commissioned here in the S.F. Bay Area for several months until they decide where to sail it next. regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] EXPLORER arrives! From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Aug 1998 09:05:41 -0700 To: SYDSAIL_at_aol.com CC: multihulls_at_steamradio.com SYDSAIL_at_aol.com wrote: > > > > Yes, but what was the total time for their crossing? Did they > > break the record they were after? > > > > Ira Heller. >From the website: http://www.therace.org/english/actualite/explorer/indexyokohama.htm Catamaran Explorer on north Pacific crossing record, Yokohama/San Francisco EXPLORER BEATS NORTH PACIFIC RECORD BY TWO DAYS NEW RECORD : 14 DAYS, 17 HOURS, 22 MN, 50 s Press announcement N 21 Sunday August 16th 1998 - 23 h 46 mn 40s GMT (Monday August 17th 01 h 46 mn 40 s French time). It was at 23 hr, 46 mn and 40 s GMT, on Sunday August 16th 1998 that the maxi-catamaran Explorer skippered by French yachtsman Bruno Peyron and American Skip Novak, crossed the finishing line, under the Golden Gate, at the end of the Pacific Ocean crossing record under sail, fully crewed, between Yokohama and San Francisco. The new record set by the crew of Explorer in 14 days, 17 hours, 22 minutes and 50 seconds means that the record held since August 1995 by American Steve Fossett in 16 days, 17 hours, 21 minutes and 19 seconds, aboard the trimaran Lakota, has been bettered by almost 2 days (exactly 1 day, 23 hours, 58 minutes and 29 seconds). Apart from the two co-skippers, the very international crew was made up of two Japanese Toru Kikushi and Kojiro Shiraishi, an Australian Paul Larsen, an Italian Elena Caputo and a young Frenchman Nicholas Pichelin. For the French skipper, the objective of this new campaign in the Pacific was essentially to improve the record time, but above all to pursue the international promotion of The Race/La Course du Mill?ire, which will start on December 31st 2000 and for which the Yokohama to San Francisco run is one of the courses along which future challengers of The Race may qualify. On arrival Bruno Peyron told us of his satisfaction : "no, the race wasn't too difficult, our very international crew was in top form. The boat worked perfectly. The objective above all was to improve this record in the perspective of The Race. What we hoped for was to mobilise our Japanese friends, interest the Americans and prepare them for the story we are going to tell them soon". As soon as the finishing line was crossed, an announcement from the Elys?Palace, in the voice of President of the Republic, Monsieur Jacques Chirac, congratulated the yachtsman and his crew, encouraging him for "the challenge he wishes to set in the race round the world, The Race". This new record of the French yachtsman is a sign, once again, of his will to work for more openness, imagination and spirit of adventure. Values which should be shared by those who, on 31st December 2000, will set out on the most extreme circumnavigation in the history of yachting. -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Fossett From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Aug 1998 09:10:25 -0700 To: KKZ-CMA Robert Hepler <rhepler_at_kkz-cma.com> CC: List - Multihulls <multihulls_at_steamradio.com> KKZ-CMA Robert Hepler wrote: > > > > Doesn't anyone else see anything wrong with this whole scenario? (I know > > there was a thread some time ago, but I don't remember if there was a > > conclusion) He is down in the ocean. Ships are diverting to rescue > > him. Why not let him float? <SNIP> > > I have no respect for people who, for whatever reasons, put themselves > > in harm's way and then expect to be rescued. May you never find yourself in need of rescue at sea because you certainly don't deserve it! In fact, with this kind of attitude, you better not walk across the street because if you get hit by a car, people might say "Why not let him die?" Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Fossett From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Aug 1998 11:33:03 -0700 To: Paul Breed <Paul_at_rasdoc.com> CC: Multihulls_at_steamradio.com Paul Breed wrote: > > > > I think you are ALL missing the point. <snip> > > I believe that many miss the days of adventure in this almost fully > > explored world. I ,for one, have been following Steve's adventures > > on a daily basis. I would love to have the Mean$ to live Steve's > > adventurous life. Things like this make it worth getting out of bed. > > > > I will gladly support any Tax's raised to fund the adventures of men. > > I would much rather contribute to the rescue costs of Mr Fossett, > > than the rescue costs of some stupid boater that had too much > > to drink ran aground and sank. <snip> YES! Judging who is worthy of a "free" rescue and who must pay to be rescued is playing God. Who is to say how well prepared is the cruiser who gets in trouble vs. the racer (or balloonist)? Bruno Peyron stated yesterday that safety is the number one concern at all times on EXPLORER. It is likely that "extreme adventurers" such as these men are far better prepared to handle the unexpected than many fishermen who work at sea every day (and are _often_ the focus of rescues at sea). Dwelling on the relatively small costs of a rescue mission compared to the billions spent annually on weapons and for the subversion of third world countries (by the USA, not Australia!?) is "penny-wise and pound-foolish". The positive world-wide publicity for Australia from this event far surpasses the minor expense involved. You said it very well, Paul, and let me quote you again here: "I would love to have the Mean$ to live Steve's adventurous life. Things like this make it worth getting out of bed." My sentiments exactly! Joseph Oster P.S. re Robert Hepler's remark "Individualism is the key. Read "Atlas Shrugged" by Ayn Rand", I can only say that individualism taken to the extreme is isolationism. Give me the company of men like Steve Fossett and Bruno Peyron any day... -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] Peyron's comments on The Race From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Aug 1998 16:18:09 -0700 To: MHml <multihulls_at_steamradio.com> CC: Jim Antrim <antrimna_at_hotcoco.infi.net> FYI, a few comments by Bruno Peyron that I remember from the press conference yesterday (paraphrased): EXPLORER has a top speed of 37 knots. The next generation of "unlimited" multihulls for The Race will be capable of a) speeds up to 45 knots(!), b) 600+ miles per day and c) making the Yokohama to San Francisco run in ten days (vs. their new record of 14.7 days). While monster designs (150') were initially considered for The Race, designers quickly realized and have tacitly agreed that 35-37 meters (115-120 feet) cats or tris is the practical upper limit using available sailing gear and methods. The hulls can easily be made larger but the winches, blocks, standing rigging, etc., would require major R&D efforts and engineering advances that aren't feasible in time for The Race. He said that on the largest available drum winches, it isn't possible to ease a sheet in the conventional manner (for example). Joseph Oster P.S. Personal observation: Sails and gear for a 120 catamaran would easily drive a 160' Pacific proa... :) -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Fossett From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Aug 1998 22:17:40 -0700 To: "Kevin O'Neill" <oneill_at_airmail.net> CC: multihulls_at_steamradio.com Kevin O'Neill wrote: > > > > People like Fossett do things like this because the papers and TV tout them > > as heroes. NOT!!! Having met Steve Fossett on several occaisions, I can tell you he is rather shy and reserved... IMHO, he seems to me to be doing these adventures soley for personal satisfaction, not public glory. He _REALLY_ enjoys himself and does very little to promote his own heroics (which I believe are genuine). Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Re: How many angels ? From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Aug 1998 22:30:32 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com, rlechner_at_erols.com Bob Lechner wrote: > > >> > >It seems that the real issue here is the desire by the historically >> > >minded on this list to restrict the use of the term proa to what they >> > >believe is the boat which is the end point of over [xxx] years of >> > >development by the Polynesians. These historians seem to believe so >> > >strongly in this hypothesis that they regard any modern boats which do >> > >not embody what they think are the essential structural features of the >> > >optimized craft as defective mutants not worth of the term proa. and Craig O'Donnell replied: > > Bob, I think you're getting worked up over nothing here, because you've > > pretty much misunderstood completely what Hans, and I, and Mark B., and > > others have been slowly working toward. No, I think Bob got it exactly right and he said it _very_ well... These efforts at splitting hairs over established terminology ARE alienating people, even within the proa faithful (like myself). I can't even be bothered to read these long posts anymore. Better things to do. The volume of EMail on this topic has become a real burden. > > My apologies to others for repeating... Please, no more repetition! Enough already. zzz, (snoring sound) Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] Re: Latitude 38 article about Russ Brown From: Joseph Oster <oster_at_wingo.com> Date: Tue, 18 Aug 1998 08:06:57 -0700 To: Thomas Henry <tomhenry_at_direct-connection.com> CC: MHml <multihulls_at_steamradio.com> Thomas Henry wrote: > > > > Is there any possibility that you are arranging to post the article and > > picture(s) from the 'Latitude 38' article (about Russ Brown) on your > > "Sailing Proa" pages? I'll have to ask about creating a link to the page but I have scanned the article and posted it here: http://www.pacificproa.com/brown/lat38-aug98.html Once again, better photos can be found here: http://www.pacificproa.com/brown/jzerrophotos.html regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Fossett From: Joseph Oster <oster_at_wingo.com> Date: Tue, 18 Aug 1998 08:16:19 -0700 To: "Cummings, John" <john.cummings_at_aetna.com> CC: multihulls_at_steamradio.com Cummings, John wrote: > > > > why wouldn't steve want to have his own chase boat staying with him? The balloon cruises at speeds as high as 145 MPH or more!!! And before you suggest the same thing for each Whitbread or other racing sailboat, I can assure you that it's equally unfeasible. Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Re: How many anglos, anyway ? From: Joseph Oster <oster_at_wingo.com> Date: Tue, 18 Aug 1998 16:15:39 -0700 To: Craig O'Donnell <dadadata_at_friend.ly.net> Craig O'Donnell wrote: > > > > Sorry you feel alienated. You don't sound sorry enough to DROP IT... > > But I don't whine publicly on the list about it. Public whines are a real > > turnoff on a good, active list. It's just one of those "rules of the road" > > of the internet and sort of an online Miss Manners thing. ZZZ > > The "volume of email" on proa > > terminology has been miniscule compared to the volume of email on the sort > > of topics Rod Gibbon likes. The volume of email on proa terminology, as well as much of its content, has been absurd! I've been getting 75 messages a day lately from the MhMl, mostly about arcane words to describe things that already have commonly accepted names. > > Live and let live already, hey? In this case, I prefer the James Bond/Paul McCartney lyric: "Live and let [it] die" Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Explorer Pix? From: Joseph Oster <oster_at_wingo.com> Date: Thu, 20 Aug 1998 07:31:43 -0700 To: R&J Morse <jmorse_at_jps.net> CC: "'multihulls_at_steamradio.com'" <multihulls_at_steamradio.com> R&J Morse wrote: > > > > Joe Oster, > > When do we get to see the pictures of Explorer flying a hull in San Francisco bay? So sorry... I didn't take any photos! Not only did I not have a camera but was too busy driving the press boat and just _LOOKING_ in total awe... Several times EXPLORER passed across our bows at high speed followed by a cloud of spray that passed over us; a baptism of sorts, definitely an epiphany type experience! Duff was there with camera so I hope he got some shots and will share them with us when he gets home. You should have seen the short video they had at the press conference to promote The Race!!! Oh my... Cheers, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Lew McGregor and Better? From: Joseph Oster <oster_at_wingo.com> Date: Thu, 20 Aug 1998 19:36:12 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com, Kiran Pamnany <kp_at_trillium.com> Dick Newick wrote: >> > >Right now Lew McGregor is sailing his 37' Russ Brown proa from the >> > >Chesapeake to Maine. A sistership is for sale on Martha's Vineyard at a >> > >reasonable price. Russ probably has more practical proa knowledge than >> > >anyone outside of the South Pacific. Craig O'Donnell wrote: > > > > I see. Is McGregor's boat normally kept somewhere on the Chesapeake? I'd be > > very interested to go take a look sometime. Lew McGregor and his proa Cimba usually reside in Fort Pierce, Florida. As you may recall, a photo of Lew's boat can be found here: http://www.pacificproa.com/brown/bolduc.html And, of course, the sistership for sale on The Vineyard is Kauri: http://www.pacificproa.com/brown/ To the best of my knowledge, Russ has (so far) designed and built a total of only four proas: 1) 30' JZERO of Polygor, 1978: http://www.pacificproa.com/brown/jzero78.html 2) Kauri 3) Cimba 4) 36' JZERRO: http://www.pacificproa.com/brown/jzerrophotos.html and: http://www.pacificproa.com/brown/lat38-aug98.html I haven't seen the first one that Mark Balogh sailed but each of other three is a masterpiece of construction and attention to detail. "Real boats for real sailors"! BTW, re Better? (the question from Kiran Pamnany): "Payload/foot: A flying proa can carry more weight than a regular multihull of the same size". As someone else already mentioned, exactly the opposite is true for the Pacific proa style. This reality accounts for the statement on my proa page: "The unique weight-distribution characteristics of the Pacific Proa give it the longest possible waterline for any given weight and rig! This is another way of saying it is (potentially) the lightest possible boat for any given length. Hence, more easily driven, faster for any given sail area, more comfortable motion at sea, (potentially) safer due to lower sail area/length ratio, etc. And the downside: highest slip fees for any given weight. regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] Re: Jzero From: Joseph Oster <oster_at_wingo.com> Date: Fri, 21 Aug 1998 09:26:25 -0700 To: James Richardson <island_at_world.std.com> CC: MHml <multihulls_at_steamradio.com> James Richardson wrote: > > > > Joseph, > > > > I believe I recall the first Jzero (which I saw and sailed on, briefly, in > > 1977 with Russ before he departed North, VA for points south) was named > > after a Cat Stevens song. I think Russ spelled the name JZERO (one R), at > > least I think he did to begin with. I will delve into my archives and try > > to reconfirm that... > > > > Just a small piece of trivia. Thanks James! You are right. I re-examind the 1988 Wooden Boat article and it was spelled with only one 'R'. His current 36' proa, however, _IS_ spelled with two; the name painted on the boat is 'JZERRO'. I also noticed in the WB article that there was a fifth proa from Russ (his first), built in the Rio Dulce, Guatemala: "the family dinghy with oars lashed across its rails and a surfboard tied to the blades". The article also mentions that Russ was "profoundly influenced" by a gift from Dick Newick, a copy of "'Project Cheers' (Adlard Coles, 1969), a book detailing the saga of [Newick's] giant-killing Atlantic proa" which "Russell devoured ... immediately and reread it several times". regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Ted Benze "Smart Sail" From: Joseph Oster <oster_at_wingo.com> Date: Mon, 24 Aug 1998 18:12:11 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com, "Munkelt, Dana" <Dana.Munkelt_at_Unisys.Com> Craig O'Donnell wrote: > > > > Anyone know anything about this? I've run into a picture and a blurb in a > > local sailing mag. Yes, I've seen the video. We did consider it briefly for the 68' proa but decided that while it appears to be "convenient" in some respects, it wasn't highly efficient. Also, as it is somewhat complicated with a good deal of weight aloft, it isn't clear that it would scale up well to the size we needed... Very interesting though! Somewhat similar to various suggestions I've received for solving the problems associated with a "balanced lug rig" for the proa. Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Re: Theory to Practice : A challenge ! From: Joseph Oster <oster_at_wingo.com> Date: Tue, 25 Aug 1998 09:41:59 -0700 To: twarren_at_alum.mit.edu CC: multihulls_at_steamradio.com, Mark Balogh <batwing_at_kerrlake.com> Ted Warren wrote: > > > > In my view, shunting is not an asset but a requirement > > forced on the form (proa) in payment of using the > > positive attributes of a proa, mainly that for a given > > weight the boat can be longer, or at a given length the > > boat can be lighter. True, but let us not forget that shunting _CAN_ indeed be a _MAJOR_ asset when manuvering in a crowded harbor. No other sailing vessel gives more complete control than being able to stop on a dime and reverse direction where convetional tacking may be impossible. And it applies equally well with large and small proas. As to this proposed race, no one has said it better than Mark Balogh: "Everyone starts with the same stack of materials". I personally don't care whether it's low-tech or hi-tech material... The [well-designed and built] Pacific proa will utilize these materials to produce a faster boat. That, in a nutshell, is the entire point. regards, Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Theory to Practice From: Joseph Oster <oster_at_wingo.com> Date: Tue, 25 Aug 1998 11:32:27 -0700 To: "Capt. Len" <trikinimaster_at_trikini.com> CC: Multihull List <multihulls_at_steamradio.com> > > Joseph Oster said: > > > > True, but let us not forget that shunting _CAN_ indeed be a _MAJOR_ > > asset when manuvering in a crowded harbor. Capt. Len wrote: > > > > Can you expand on this ? <snip> > > Under these conditions it would seem the vessel is at the mercy of wind > > and tide. <snip> All this has been explained to you, Capt., and it seems you just don't get it...<BG> Sail with Russell Brown just once and you will understand. Theory is no substitute for experience! > > If your refering to using the paddle to turn the ends then it wouldn't > > apply equally to large or small craft. I am certainly not refering to the use of paddles to manuver the craft at all. With wind abeam, when you swing the boom from one end to the other, the boat suddenly stops and instantly reverses direction. The speed of this manuver is entirely up to the helmsman. I have seen Russ stop his 37' proa within six inches of a dock and hold it there while people hop aboard, then gracefully "back" away and take off in the opposite direction. Try it, you'll love it! <BG> And shunting is more than just an "artifact". It is the natural result of keeping a single small hull to weather for stability rather than depending on the second (or 3rd) hull for buoyancy to leeward. Hello? <BG> regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: Re: [MHml] Theory to Practice From: Joseph Oster <oster_at_wingo.com> Date: Tue, 25 Aug 1998 21:06:14 -0700 To: "Capt. Len" <trikinimaster_at_trikini.com> CC: Multihull List <multihulls_at_steamradio.com> Capt. Len wrote: > > > > Look it is impossible to decide any issue by discussing anecdotes. In other words, "Don't confuse me with the facts"? <BG> > > There are basic laws of physics. Well, duh! <BG> > > The small OR doesn't provide the stability but rather it is simply > > where one places weight to gain stability. Grasping at straws here Capt.! <BG> Lecturing me about how a proa works is preaching to the choir and totally unnecessary. > > Not sold. Sorry <BG> You can lead a horse to water but you can't make them drink. <BG> I have no interest at all in converting you Capt. And nothing you've said changes my mind either. Like I said, there is no substitute for real experience. Joseph Oster -- http://www.pacificproa.com/ (415) xyz-1234
Subject: [MHml] EXPLORER's size! From: Joseph Oster <oster_at_wingo.com> Date: Wed, 26 Aug 1998 20:45:27 -0700 To: MHml <multihulls_at_steamradio.com>, BAMA ml <bama_at_tango.rahul.net> Tonight I rowed a dinghy out to my 24' trimaran on it's mooring at the Corinthian YC, then another hundred yards to the 86' EXPLORER on a nearby mooring. It's hard to tell from a distance how big it is! The bows have 6.5 feet of freeboard!!! I can stand under the formost (headstay) beam which is nearly seven feet off the water! The two large connecting tubes are 18-20 inches in diameter. http://hobie18.dyn.ml.org/explorer/exp_bows.JPG http://hobie18.dyn.ml.org/explorer/exp_k3.JPG regards, Joseph Oster P.S. to BAMA members: more photos: http://hobie18.dyn.ml.org/explorer/ http://www.teamronin.org/gallery2.htm http://www.therace.org/english/actualite/explorer/indexyokohama.htm -- http://www.pacificproa.com/ (415) xyz-1234
Subject: Re: [MHml] Pacific Canoe Site From: Joseph Oster <oster_at_wingo.com> Date: Mon, 21 Sep 1998 13:59:30 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com Craig O'Donnell wrote: > > > > traditional canoes on Taumako, which is over away down near Tikopia and > > Anuta, Polynesian outliers which are a little more famous than Taumako > > itself. > > >> > > http://www.planet-hawaii.com/vaka/intro.htm I recently created this page for a friend here in Sausalito with a "tradtional" proa modeled after those in the Santa Cruz Islands, mentioned in Canoes of Oceania: http://www.pacificproa.com/davidcoy/ It has a link at the bottom to "PICA: Pacific Islanders' Cultural Association": http://www.pica-org.org/ regards, Joseph Oster -- http://www.JosephOster.com (415) xyz-1234
Subject: [MHml] Fossett's catamaran From: Joseph Oster <oster_at_wingo.com> Date: Fri, 18 Dec 1998 10:14:28 -0800 To: MHml <multihulls_at_steamradio.com> Hi folks, I have re-joined the list after a six week absence. During that time, I sailed a 63' catamaran owned by Richard Spindler (Latitude 38 sailing magazine, http://www.profligate.com/) from San Francisco to Puerto Vallarta including stops in San Diego, Cabo San Lucas and a couple of places along the Baja California coast. Great time! I haven't seen anyone here mention the fact that photos of Steve Fossett's new catamaran have been posted on "The Race" web site: http://www.therace.org/english/challengers/potentiel/fossett1.htm Apparently the launch is scheduled for December 21st, assuming he survives his current balloon expedition with Richard Branson. They took off today: http://www.icoglobal.com/ regards, Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] Steve Fossett and THE RACE From: Joseph Oster <oster_at_wingo.com> Date: Sun, 17 Jan 1999 11:19:51 -0800 To: multihulls_at_steamradio.com CC: BAMA ml <bama_at_tango.rahul.net> duff sigurdson wrote: > > > > Discover the first outing photos, > > visit the maxi-catamaran on video, > > see the boat's specifications, > > the profile of Steve Fosset and Playstation's press releases on: > > > > http://www.therace.org/english/actualite/indexactu.htm > > > > http://www.therace.org FYI - For anyone who hasn't been able to enjoy the 300 DPI files available on the above page, I have created a cropped, 72 DPI full screen .JPG version visible here: http://www.JosephOster.com/sailing/playstation.jpg WOW! Joseph Oster -- http://www.pacificproa.com/ (415) 332-0421
Subject: Re: [MHml] Steve Fossett and THE RACE From: Joseph Oster <oster_at_wingo.com> Date: Sun, 17 Jan 1999 16:41:38 -0800 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_steamradio.com, BAMA ml <bama_at_tango.rahul.net> Dave Culp wrote: > > > > Hey, did you flip the negative on the above scan, or did they? Nice boat, > > that "noitatsyalP" ;-) Thanks for re-posting it, at any rate! The photo was flipped on their web site! But I have fixed it and re-posted both images here: http://www.JosephOster.com/sailing/fossett/ Now about that "dolphin striker" holding down the bow sprit...(!) Looks kinda vulnerable hanging down there, doesn't it? Cheers, Joseph Oster -- http://www.pacificproa.com/ (415) 332-0421
Subject: Re: [MHml] Catamarans--self righting ? From: Joseph Oster <oster_at_wingo.com> Date: Thu, 21 Jan 1999 22:34:53 -0800 To: "Robert L. Hobbs" <DynaWing1_at_webtv.net> CC: multihulls_at_steamradio.com "Robert L. Hobbs" wrote: > > > > I think that we will someday have self-righting Cats, > > even very big ones. There aren't any physical laws staning in the way, > > so it will be done. Have you ever crossed an ocean? Are you familiar with 35 knot winds (or more!) and 18' seas (or more)? Have you ever sailed a large (76') racing catamaran at 27 knots? Or even a more modest cruising design such as this 63 footer? http://www.profligate.com/profligate-l.jpg Do you really believe a 100' wing mast is going to somehow keep it from tipping more than ninety degrees and then be structurally sound enough to continue sailing? In the first place, it is fairly difficult to tip them over anyway and would likely occur in only the very roughest of conditions (BIG WAVES and wind)... But if you manage to do so far enough for the mast to hit the water, I'm quite certain that recovery in a cat or tri is EXTREMELY UNLIKELY! To increase stability, much effort is given to reducing weight aloft and yet your proposals would inevitably work in the opposite direction. And for an event that is rare and easily avoided in the first place. > > Now, who in the world said anything about a Cat going over endo, pitch > > poling ? I didn't. "self-righting" implies that it doesn't matter how it goes over. What you are really talking about is capsize resistance. My suggestion is that you look at Pacific proas! It is ironic that what appears to be an unstable hull form has the potential, with proper design considerations of the leeward "pod", of being the most difficult multihull to tip over. Seriously! > > widely thought to be impossible in the past. Man does the "impossible" > > every day, and will continue to do so. And, those who stand on the > > sidelines screaming;"It can't be done !" will also continue to do so. > > That's just the way humans are----sadly. Yawn... You are preaching to and dismissing some very remarkable, creative and knowledgable people on this mailing list, just because you have been challenged on your ideas. Frankly, I'm not convinced you understand things (or respect the members of this list) well enough for me to bother reading your often lengthy arguments. Joseph Oster -- http://www.JosephOster.com (415) 332-0421
Subject: Re: [MHml] Catamarans--self righting ? From: Joseph Oster <oster_at_wingo.com> Date: Fri, 22 Jan 1999 13:16:38 -0800 To: "Robert L. Hobbs" <DynaWing1_at_webtv.net> CC: MHml <multihulls_at_steamradio.com> "Robert L. Hobbs" wrote: > > > > You play it safe---The trunk of the tree is where all of the strength > > is---I'll go out on a limb, because that's where the fruit is.<BG> If you think my interest in the Pacific proa (the "lunatic fringe" of the multihull fringe) is "playing it safe", you simply aren't paying attention. Virtually everyone on this list is a rebel to a degree, some more so than others. Your long diatribes extolling your innovative rebel approach and treating the rest of us as conservative traditionalists with limited imagination is unbelievable!!! It's insulting and a waste of time and bandwidth. Dealing with the facts and totally dropping your persecuted rebel crap would go a long way towards establishing your credibility. Declaring yourself the only enlightened rebel among us is utterly deluded and completely absurd. Joseph Oster -- http://www.pacificproa.com/ (415) 332-0421
Subject: Re: [MHml] Playstation. From: Joseph Oster <oster_at_wingo.com> Date: Tue, 16 Feb 1999 06:31:49 -0800 To: Roy Mills <rsirfj_at_mars.ark.com> CC: multihulls_at_steamradio.com Roy Mills wrote: > > At 10:44 PM 2/15/99 -0800, you wrote: >> > > Mr Morelli obviously disagrees and he,equally obviously knows more about >> > >this than I do. So, like I said at the beginning, Time for another lesson. >> > >Where am I in error in my long held belief, supported as it is by streaming >> > >telltales? and Duff Sigurdson replied: > > > > Perhaps it is more smoke from M&M.... Steve likes to play games to keep us > > all guessing... see my earlier comments regarding this mast. Excellent point Roy!!! And I think Duff may be on the mark here too. Your observations match my own experience as well. One of the odd and very interesting features of the proa (excuse me folks!) is that because the _BOOM_ rotates 180 degrees on each tack, a near stationary wing mast appears "rotated" 90 degrees relative to the boom on either tack! This happens to be ideal for high performance sailing; it happens on the proa with little or no movement of the leading edge wing relative to the boat! See photo: http://www.pacificproa.com/brown/jzerro13-l.jpg from: http://www.pacificproa.com/brown/jzerrophotos.html Cheers, Joseph Oster -- http://www.JosephOster.com (415) 332-0421
Subject: Re: [MHml] Big Proa From: Joseph Oster <oster_at_wingo.com> Date: Thu, 25 Feb 1999 10:11:20 -0800 To: Dave Culp <dave_at_dcss.org> CC: multihulls_at_steamradio.com Dave Culp wrote: > > > > I'm thinking about a big proa, some 100-110' LOA... What a wonderful vision Dave! You make a _LOT_ of sense to me there. Your specs and details match my own in many respects. As you know, I've spent a lot of time contemplating a 68 foot (21 meter) Pacific proa design and also given some thought to a scaled up version for "The Race"... Briefly, a few observations and differences: Dave Culp wrote: > > > > I have in mind building this boat on a budget suitable to a 60-70' > > "conventional" multi, though I'm hesitant to put dollar figures to it. Depending on level of finish, I would hazard a guess of 3/4 million dollars minimum for 110' and nearly half that for a 68' version. Including professional labor, even a "small" new 40' blue water proa would cost as much as an F27; nearly $100K? As to your rig ideas, I share your fondness for the wishbone and have worked with Antrim to develop a "Bucky Boom" variation that also holds a headstay to balance the main sail when it shunts 180 degrees: http://www.pacificproa.com/rig.html However, the automatic aspects of controlling the main boom with a trailing wing are first and foremost (by your own argument below) virtually unnecessary! > > want wishbone booms, but not aerorig/baelestron rigs. I want the rigs to > > be self-controlled, via solid-wing empennages, at the end of the > > wishbones (ala Walker Wingsails, or Bob Quinton's Boatek Foilsail's > > well-proven wings ( http://www.boatek.demon.co.uk ), and yet the rig may > > be controlled by conventional sheets, as well. > > Auto-control of booms/sails. With vertical tail surfaces, mounted at the > > ends of wishbone booms, plus perhaps some wingmast area forward of their > > pivots centers, this boat is ripe for automatic control. And yet in a later reply, Dave wrote: > > > > No. With wishbone booms, there is no sheeting problem at all. The boom > > creates all outhaul and downhaul tensions, so the sheet only controls the > > boom's angle of attack. There's little sheet tension, and most > > wishbone-boomed sails use a one- or two-part sheet only. A simple > > purchase to the hull is all that's necessary. [etc.] As Russ Brown's deck layout demonstrates, taking even heavy sheeting loads to and between hard points as the boom swings 180 degrees is "easy" (when you know how). And as you say yourself, with a wishbone and possibly balanced rig, "there is no sheeting problem at all"! So a trailing wing control does what? It seems very clear to me that while fascinating and potentially useful in sustaining maximum possible performance, such a system is vulnerable and of higher complexity than simply sailing the boat (and sheeting the main) in a conventional manner. On a large stable yacht, keeping the weather hull flying consistently has more to do with steering than sheeting... Again, IMHO, this feature is interesting but non-essential to the overall concept. > > As to structure, exotic materials could be used, but I ran the weights > > without: Main hull, ave. thickness 0.75" <snip> > > Ama similarly constructed, ave. thickness 0.50" While specific weights are a function of materials and cost, these thicknesses seem barely adequate to me for the 1/2 scale version, eh? The full size 30+ meter yacht would likely use foam hulls closer to twice that thick, as does Double Bullet II (76' cat) and Profligate (63' cat). > > I see using the > > tried-and-proven dual daggerboard/aft rudder combination of Cheers and > > Tiny Dancer, scaled up to fit this boat. As to steering a large yacht, I have become convinced that raising and lowering rudders or dagger boards on each tack is an unnecessary burden... Dual full time rudders, counter rotating and connected by a conventional Whitlock driveshaft system (as used on Profligate) is the strong and easy way to go. This system supports multiple steering stations, very low friction. (see rudders on above rig diagram) Both rudders should be retractable for repairs, beaching or storm survival tactics but otherwise left down all the time. Yes, the forward rudder is vulnerable... Designing it to survive a heavy blow (or fail gracefully) is challenging but not impossible. Carrying spares is a good idea too. > > Auxilliary power, I'd think, could be a single inboard diesel Would be nice to find a way to put the inboard diesel out in the ama and still propel the boat somehow, just to keep the noise and fuel away from the cabins while generating electricity, pumping water, etc. Great work!!! I _REALLY_ enjoy seeing someone else take these boats at this scale so seriously and in such detail. Thanks for sharing! Cheers, Joseph Oster -- http://www.pacificproa.com/ (415) 332-0421
Subject: Re: [MHml] No free lunch (was:Re: Stability, again) From: Joseph Oster <oster_at_wingo.com> Date: Mon, 08 Mar 1999 21:33:16 -0800 To: twarren_at_alum.mit.edu CC: multihullboatbuilder_at_direct-connection.com, Multihull Mail List <multihulls_at_steamradio.com> Well considered as always Ted! However... Ted Warren wrote: > > > > An ama will weigh around 12% of the total weight of the boat. For a Pacific proa, > > that and 1/2 of the weight of the beams is all that it has to generate righting moment. Actually, following Russ Brown's example on Kauri, I've always planned to achieve 25% of total yacht displacement supported by the ama. At the scale of our 21 meter Pacific proa design, that means locating a great deal of heavy stuff like batteries, engine, diesel fuel, etc. in the ama. Second, the dramatic increase in stability resulting from an adequate volume of "leeward pod" hitting the water at 30 degrees of heel must not be overlooked! This narrows the range of instability between the ama leaving the water and the pod entering the water; again, only 30 degrees or so. We have found that with proper pod volume and position relative to the proa's CG, the second plateau of the stability curve can be even higher than the first! That is, it resists heeling even harder when tipped 30 degrees or more onto the pod than it does when the ama is just leaving the water. Third, sufficient and separate tankage in the ama bows to take on seawater ballast resulting in 33% of total yacht displacement supported by the ama (usually reserved only for extreme sea conditions). The ability to shift the water ballast aft on each shunt will be a plus, though again, I don't see the use of ballast as routine. Finally, that an ama will fly "all the time" is likely unrealistic. In cruising mode, it may rarely happen at all depending on the comfort and skill level of the crew. There are still benefits of the shorter and smaller hull to weather, even without flying the hull completely. The unshakeable virtue of the Pacific proa configuration is a longer waterline for a given displacement. The stability calcs look very different with 25% normal displacement in the ama (sans ballast) and a large, high leeward pod of reserve buoyancy if a knockdown should occur. Cheers, Joseph Oster -- http://www.pacificproa.com/ (415) 332-0421
Subject: Re: [MHml] Tilted Sails From: Joseph Oster <oster_at_wingo.com> Date: Sat, 10 Apr 1999 13:18:36 -0700 To: multihulls_at_steamradio.com ETMCEDG1 wrote: > > > > Barkla 1951, made drawings of tilted sails. <snip> > > Has any further work been done on this? > > Anybody built it ? No one has yet mentioned Dick Newick's 1988 singlehanded trans-Atlantic trimaran "Ocean Surfer" which had the base of its wing mast mounted on a curved track on the forward crossbeam. This allowed the mast to be tilted to weather on either side, though the angle was limited by the reduced support of the leeward shroud as the mast angle approached maximum. Mark Rudiger sailed the boat in the 1988 CSTAR and commented that though the feature was rarely used (perhaps because of singlehanded concerns about getting caught aback), he believed it increased performance in a light air situation enough to catch and pass a competitor. I have scanned four photos and put them here: http://dicknewickboats.com/oceansurfer.html Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: [MHml] PlayStation Fire From: Joseph Oster <oster_at_wingo.com> Date: Sat, 24 Apr 1999 12:10:12 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net>, multihulls_at_steamradio.com Joseph Oster wrote: > > > > Your comments sound way off base to me, like disguised envy? P.S. As I recall, we had this very same discussion once before when Fossett's balloon fell into the southern ocean... I have no interest in trading flames or getting philosophical on a subject that has more to do with "prosperity consciousness" than multihulls, especially with a fellow proanaut. Suffice it to say that your remarks sound to me like somehow Fossett deserves to have his boat burn up! And whatever reasons someone has for saying so, I don't believe you would like it said about you and your boat anymore than he (or I) like it being said about PlayStation. I prefer a proa to a catamaran in part because it conserves resources but I strongly believe large boats are safer than small ones, racing or otherwise. That boats of this size cost millions is a sad reality, just like clipper ships of their day weren't affordable to everyone. Doesn't make 'em irrelevant! BTW, I have it on good authority that "they were using a new kind of battery to save weight"... regards, Joseph -- http://www.JosephOster.com (707) xyz-1234
Subject: [MHml] gybing a proa From: Joseph Oster <oster_at_wingo.com> Date: Sat, 08 May 1999 13:43:54 -0700 To: Pete McDowell <P.McDowell_at_Queens-Belfast.ac.uk> CC: multihulls_at_steamradio.com I must belatedly differ with recent replies on the distinction between a "gybe" and a "tack" ('just another shunt') on a proa... There _IS_ a difference! Any standard tack (or shunt) passes the wind around the _leading_ edge of the boom and mast with main sail luffing until pulled "aft" on the new tack... A gybe passes the wind around the _TRAILING_ edge of the boom, like any other boat, and the force on the main sail is VERY SUDDENLY reversed! On the Pacific proa with a modern rig, it can be done with the boom "safely" secured amidships, directly opposite of the small hull to weather. Without a balanced rig it would be done on main alone and the jib raised later after the maneuver. Besides the usual sudden change in load of any gybe (passing the wind over the _trailing_ edge of sail), the risk of plastering the boom and main sail against the shrouds from the wrong side of the boat is also a risk. While this must be totally avoided with traditional rigs, it is feasible with modern ones, especially using a free standing mast and "balanced boom" jib. My remarks are based on a dozen or more day sails aboard Pacific proa style craft of 37 feet with 75% of vessel displacement in the larger, longer hull to leeward, small hull "flying" (lifting) to weather. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 > > On Wed, 5 May 1999 07:35:02 +1200 Gary Dierking <garyd_at_wave.co.nz> > > wrote: > > >> > > fail to see how a jibe is even possible with the traditional rig. and Pete McDowell wrote: > > > > What I was loosely referring > > to as "a gybe" was really whatever manouvre you would perform in a > > proa to change say from one very broad reach to another very broad > > reach with about 60 degrees of a difference in course. It's not > > really a gybe at all, but hey, "a gybe" sounds much neater! > > Afaik in a proa this would be 'just another shunt' - but from reading > > proa postings I think there is more to it than that, is this the case? > > If it's not can you (or any other proanauts) give us the details?
Subject: Re: [MHml] gybing a proa From: Joseph Oster <oster_at_wingo.com> Date: Tue, 11 May 1999 07:48:11 -0700 To: Dave Howorth <Dave.Howorth_at_acm.org> CC: multihulls_at_steamradio.com > > Joseph Oster wrote: >> > > >> > >A gybe passes the wind around the _TRAILING_ edge of the boom, like any >> > >other boat, and the force on the main sail is VERY SUDDENLY reversed! >> > > >> > >On the Pacific proa with a modern rig, it can be done with the boom >> > >"safely" secured amidships "amidships" was a confusing word here... More precisely, it is: On the Pacific proa with a modern rig, it can be done with the boom secured at ninety degrees to the main hull (to leeward during a normal shunt/tack) of the proa, directly opposite of the small hull (to weather during a normal shunt/tack). Dave Howorth wrote: > > > > I'm not sure I understand this. Is it a manouevre where the boat revolves > > 270 degrees or so, putting the main into the wind and the small hull to > > leeward whilst doing it? In what circumstances would one consider this in > > preference to shunting the boat through about 90 degrees (or in any case > > smaller than the 'gybe' angle), keeping the small hull to windward and the > > sail in a controllable situation? I believe you have described the situation beautifully! A dazzling full power 270 degree spin and whoosh out of there! Or an embarrassing flounder with the sails against the rig... Generally no good reason to gybe a proa except that such accidents do happen. Fully visualizing and mastering the recovery is an early practical skill and who knows, the move might have some advantage in competition if it doesn't break the equipment. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] Proas and racing From: Joseph Oster <oster_at_wingo.com> Date: Tue, 11 May 1999 07:48:18 -0700 To: Roy Mills <rsirfj_at_mars.ark.com> CC: multihulls_at_steamradio.com Roy Mills wrote: > > > > Any chance of getting a good argument going about whether Dynawing canting > > keel boats are really proas which tack and shift their log from one side to > > the other as they do so :^). No argument from me! An excellent vision of the Pacific proa with its buoyant ballast barely flying way out to weather... Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] Fastest boat for $3.95 ? From: Joseph Oster <oster_at_wingo.com> Date: Fri, 16 Jul 1999 09:46:53 -0700 To: multihulls_at_steamradio.com Not sure who wrote: > > >> > >I'm pretty sure I read somewhere that an early "discoverer" of Polynesia >> > >(as if the inhabitants were "lost")--perhaps Cook--wrote that the local >> > >flying proas were doing "better than 20 kts." Not sure of the quote, but >> > >pretty sure of the sentiment. Maybe Canoes of Oceania? http://www.pacificproa.com/flyproa.html "From some rude estimations made by our people of the velocity with which they crossed the horizon at a distance, while we lay at Tinian, I cannot help believing that with a brisk tradewind they will run near 20 miles an hour, which, though greatly short of what the Spaniards report of them, is yet a prodigious degree of swiftness..." Canoes of Oceania, Volume 1, p. 413..415 - An account by Baron George Anson in the year 1748. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] Fastest boat for $3.95 ? From: Joseph Oster <oster_at_wingo.com> Date: Fri, 16 Jul 1999 13:36:52 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com Craig O'Donnell wrote: > > > > So why don't we say 12-15kts and be done with it <chuckle>. 15kts=17.3mph which is to say you are splitting hairs with Anson! I think the original source in this case is trustworthy. > > Ben Finney's reports of Hokulea -- 60ft double canoe -- that they were > > seeing any extremes of speed in the 3 or 4 ocean voyages it has made. With all due respect, Hokulea is heavy and underpowered! It has no "speed" at all. Having seen it sail (actually it was towed!) into San Francisco Bay, I can say that it is hardly an example of the speed potential of ancient sailing craft. It isn't even a proa!! http://leahi.kcc.hawaii.edu/org/pvs/build.html http://leahi.kcc.hawaii.edu/org/pvs/Hokulea.gif Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: [MHml] slow mutlihulls From: Joseph Oster <oster_at_wingo.com> Date: Sat, 17 Jul 1999 20:38:29 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com Craig O'Donnell wrote: > > > > This may not be the literal truth of the boats as they existed, but it > > brings everything into a sort of useful perspective. Useful perhaps if you are desperately (and hopelessly!) trying to prove the virtues of slow sailing over "speed sailing" for which, Craig, you seem to have a peculiarly strong aversion... You aren't proving anything. Sailing fast isn't merely an elitist racing phenomenon, it is a practical solution to traversing long distances and avoiding prolonged exposure to bad weather. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] slow mutlihulls From: Joseph Oster <oster_at_wingo.com> Date: Sun, 18 Jul 1999 09:06:01 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com Craig O'Donnell wrote: > > > > This nitpicking is tedious. I count thirteen postings by you on this subject since July 7th, not including those on the proa mail list so who is being "tedious"? > > "Virtues of slow sailing"?!?! Where in the world did you get THAT? >From the many disparaging remarks you've made about sailing fast! Such as in this very reply: "And I think being obsessed with speed boats is a waste of money." And from your off-list statement: "The truth circa 1999 is I have no interest in speed sailing at all." I perceive a longstanding defense of poking along slowly in the Chesapeake where apparently you don't have room to go fast(!?). Ironic since it is the same place Russ Brown developed his first practical proa (the 1978 JZERO) and I've actually sailed there myself aboard Cimba (http://www.pacificproa.com/brown/bolduc.html). > > However, I don't accuse them of "slow speed aversion" I believe you do exactly that everytime you attempt to invalidate and ridicule someone who is willing to spend money to sail fast. > > Different courses as they say... So don't muddle the issue if you can't > > understand the point. Now you insult me which is why I bothered to reply once more... I understand your issue just fine, thank you very much! To use your own mantra, "I remain unconvinced". > > What's the theoretical hull speed of a 29-ft boat? 1.3* sqrt(wl) > > or something? That would be 1.3 * 5.4 -- that seems TOO low. Hello!? Since when have long skinny multihulls been limited by hull speed? By that formula the 50' trimaran Moxie would be limited to 9.2 knots and guess what Craig? It _averaged_ 10.5 knots across the Atlantic and could routinely sustain eighteen knots. > > My "opinion" is that the broad generalization is inaccurate, and that the > > boats, on average, were sailing well below 20 mph. You've made your opinion quite clear. My opinion is that these Pacific islanders, who's sailing craft you've documented so well on your web sites, might have been much more interested in going fast than you are! Joseph Oster -- http://www.pacificproa.com/links.html (707) xyz-1234
Subject: Re: [MHml] Fastest boat for fewest dollars From: Joseph Oster <oster_at_wingo.com> Date: Mon, 19 Jul 1999 18:49:57 -0700 To: Shoestring Shipyard <jacktar_at_shoestringshipyard.com> CC: MHml <multihulls_at_steamradio.com> Shoestring Shipyard wrote: > > > > What seems to detract from this great forum though, is some of the petty > > bickering and name calling between several individuals due to (apparently) > > simple disagreements. Craig O'Donnell has been pontificating on this list for years on the subject of slow vs. fast sailing. To my knowledge, he has never been attacked for enjoying a lower level of performance than many of us have come to expect from multihulls. Yet at every opportunity he has assailed and insulted anyone interested in "speed sailing" as he calls it. His cruel black "humor" about the fire aboard Steve Fossett's PlayStation catamaran in April was typical. And somehow what started as a thread about "Fastest boat for $30,000" was changed to "Fastest boat for $3.95 ?" (cost being his priority over speed) while Craig dismisses the whole topic of performance with "I think it's silly to spend a million or two to 'go fast'". There's a big difference between $30,000 and a million or two but to Craig they are apparently the same. The pejorative tone of such remarks reveal the true biased nature underlying his pronouncements about ancient proas such as the following: "So why don't we say 12-15kts and be done with it <chuckle>." It is more than merely tiresome to listen to someone projecting their personal bias and lack of experience as fact, it is a distortion of the historical record. Sure Craig has _some_ valid points about the realities of two hundred years ago... That doesn't give him any right or authority to brow beat this list into accepting his "cheap and slow is reality" attitude. I'm absolutely certain that proa builders of that day existed who wanted to go as fast as possible, regardless of "cost" or effort. When it descends to cheap insults like "So don't muddle the issue if you can't understand the point" and "if you aren't interested in the discussion, butt on out" then I believe a rebuke is inevitable and well deserved. I am interested and understand very well that sailing as fast as the wind has been accomplished only by those who don't believe "it's silly". Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: [MHml] Fastest boat for fewest dollars From: Joseph Oster <oster_at_wingo.com> Date: Mon, 19 Jul 1999 23:17:12 -0700 To: marius <mariusrf_at_bellsouth.net> CC: MHml <multihulls_at_steamradio.com> marius wrote: > > >> > > cruel black "humor" about the fire aboard Steve Fossett's PlayStation >> > > catamaran in April was typical. > > > > I recall that instance. I wonder what happened to that miraculous fire, who > > took the blame in the end? Yes, and I recall it was you ("pal") who, among other wild and unfounded speculations said the following: "Could the whole thing have been staged (and faked) just to give the competition some false sense of security ?" What is/was your point anyway? > > Have you seen any "expensive and fast is reality" type proa? Proa or not, "expensive and fast is reality" is just as valid as "cheap and slow is reality". Both happen to be true when it comes to building ocean-going sail boats. There is nothing wrong with either statement. My objection is that Craig would have us believe that one is "silly" ("brainsplatter speed") and the other is the only approach that is reasonable ("cheap and slow"). Believe me, I'd love to go cheap and fast if possible. It is one of the primary benefits of the Pacific proa design. However, cheap or not (and that's a relative thing), I have been spoiled by the experience of crossing oceans at speed and I LOVE IT! I've grown weary of hearing from Craig that there is something wrong with this just because it is expensive. > > At last count , with the exception of very short events like absolute speed > > records , the average speeds of even the largest multimegadollar multihulls > > are still under the claimed 20kn for those driftwood derelicts with coconut > > sails. Average speed over many days of sailing is obviously increased by being able to run as fast as possible with the wind when it blows. The _average_ for the mega multihulls sailing around the world is "only" 14.5 knots or so(!!!) but to do that they must make up for calms with sustained high speed. > > I'm sure some poor proa on the verge or self destruction might have seen a burst > > speed of 16kn, but don't tell me that this was usual average In the first place, neither you nor Craig can be "sure" about much of anything that happened two hundred years ago. And in the second place, I didn't tell you any such thing! The Anson quote we are operating from here is "with a brisk tradewind they will run near 20 miles an hour". That's "near 17.4 knots" folks. Somehow that statement has been twisted all around to make it sound absurd or impossible. And the argument is being advanced by someone who has an openly stated aversion to "speed sailing", even today when beach cats can do it. > > Sure they existed and they still exist today, they all build racing proas , > > there's no practical reason for why this type of craft exists , just go > > fast. Again, for those who haven't actually done it, there _ARE_ practical reasons for cruising as fast as possible, the primary one being minimal exposure to bad weather on long passages. > > Is that a $3.95 insult? Ask Craig, it was his insult. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] Twin una-rigs on Pete Goss's Boat From: Joseph Oster <oster_at_wingo.com> Date: Wed, 21 Jul 1999 13:45:04 -0700 To: Robert Hepler <rhepler_at_yunque.net> CC: multihulls_at_steamradio.com Robert Hepler wrote: > > > > For that matter, what about a tri with twin rigs, one in each ama, or near? Totally invalidates one of the primary advantages of the tri over a cat which is having the center hull to support the rig! If you a mast on each ama then why bother with a center hull at all? Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] Guy Delage From: Joseph Oster <oster_at_wingo.com> Date: Thu, 22 Jul 1999 18:02:08 -0700 To: John Dalziel <johndl_at_istal.com> CC: multihulls_at_steamradio.com John Dalziel wrote: > > > > Subject: Re: [MHml] Guy Delage > > > > A few other sites have some info on him: > > > > http://www.guydelage.fr/ Thanks for this link! Only Javascript is required, not Java... I have added separate links for each of the three proas shown in the Gallery section to my proa links page: http://www.pacificproa.com/links.html > > "Funambule" means approx. "tight-rope walker," by the way. Does > > anybody know if there is a good picture of her on the internet? Here are four photos! http://www.guydelage.fr/francais/galerie/voile/funambule.htm regards, Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: [MHml] Twin Una Rigs From: Joseph Oster <oster_at_wingo.com> Date: Fri, 23 Jul 1999 08:35:13 -0700 To: "Metza, John" <John.Metza_at_sheldahl.com> CC: "'Multihulls Sailing List'" <multihulls_at_steamradio.com> "Metza, John" wrote: > > > > Here is an interesting link courtesy of Bob at DynaWing > > http://www.ensta.fr/~dsim/ Yes, nice photos! To make them easier to view I have separated the layers of the animated .GIF and converted each to .jpg format (quicker to download). I did not bother creating thumbnails but this page is still only half the size of the link above: http://www.JosephOster.com/multihulls/ensta/ Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] The Joe Factor!? From: Joseph Oster <oster_at_wingo.com> Date: Sat, 24 Jul 1999 00:11:30 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com Craig O'Donnell spewed: > > <snip> WOW!!! And you called _ME_ "touchy"?????? It was a friendly gesture sir; I think the thing is very cool! > > http://www.shelter-systems.com/kayak.html I respect and acknowledge the validity of your arguments (except for re-writing history) and only ask the same... In the S.F. Bay Area a house costs between $250..350K. That is my target budget for a big fast, comfortable live aboard cruising multihull. Expensive? Makes more sense to me than a house! By fast I mean occasionally 20 knots or more. Just good fun safe cruising style sailing between distant ports across oceans... Peace man, Jose -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] The Joe Factor!? (P.S.) From: Joseph Oster <oster_at_wingo.com> Date: Sat, 24 Jul 1999 00:53:29 -0700 To: "Craig O'Donnell" <dadadata_at_friend.ly.net> CC: multihulls_at_steamradio.com Craig O'Donnell wrote: > > > > You managed to kill a sensible discussion -- > > The "fastest for $30,000" thread died a natural death. My intention was to bring the discussion back to the original point, a design challenge with a somewhat reasonable budget for a small boat project. I didn't really believe $30,000 would ever beat Stars and Stripes in the Chicago-Mac Race but was willing to listen respectfully to design parameters until your carping and put downs about "the $$ factor". The reality I'm familiar with is that decent fast multihulls with any accommodation, especially those designed for the ocean, just aren't cheap! So why not accept that and think big? Your two hundred dollar proa budget is fine for you perhaps but in my view is crushing some potentially sensible discussions about realistic "low budget" projects ranging around $25K, $250K or $2.5 million. > > I have really tried, Joe, to keep my sense of exasperation within bounds. Guess you lost it this time, eh? > > Say whatever you want! Imagine that! I usually do. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] Mast Rake From: Joseph Oster <oster_at_wingo.com> Date: Wed, 28 Jul 1999 08:41:43 -0700 To: "Metza, John" <John.Metza_at_sheldahl.com> CC: "'Multihulls Sailing List'" <multihulls_at_steamradio.com> "Metza, John" wrote: > > > > Being a 30+ knot windsurfer guy, I know the advantages of raking > > a mast as speed increases, maybe we have been going about it the wrong way? > > It seems to me, a free standing rig greatly simplifies raking the mast. It seems to me, just the opposite! The only problem a free standing rig solves is keeping the mast from falling over to windward once it is past (or close to!) the angle of the leeward shrouds (headstays on a proa) and the wind goes light. Otherwise a mast stepped on the deck in a hinge seems easier to control by shortening the windward shroud. I have long felt that active control of the rig is a next logical step for large boats, similar to the way a windsurfer can absorb shock loads. However, the consequences for "blowing it" are so much more serious and expensive than simply going for a swim. I would think these are the primary reasons a windsurfer heels the mast: 1) to hang their body weight further to weather. 2) to reduce sail area. 3) to provide lift of the board. Reasons 1 and 2 have little to do with large sailing yachts, though #3 might apply. Other than absorbing shock loads over relatively small distances, however, active control of a large mast with the speed and range of angles available to a windsurfer is probably unfeasible due to power requirements alone! Duplicating the windsurfer's ratio of human body power to sail area in any sizeable multihull seems impossible, though smart technology that takes advantage of momentary light loads to make adjustments has some potential. Otherwise you are talking about a "set it and forget it" arrangement which, of course, makes any sense only on a proa since the heeled mast doesn't have to move when tacking! Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234
Subject: Re: [MHml] tilting rigs From: Joseph Oster <oster_at_wingo.com> Date: Thu, 29 Jul 1999 08:56:11 -0700 To: Chris White <cwdesign_at_ma.ultranet.com> CC: "'Multihulls Sailing List'" <multihulls_at_steamradio.com> Chris White wrote: > > > > One of the boats was an 18' proa. Very light, carbon wing mast, lots of > > fussy composite detail. This boat would occasionally exhibit blinding speed. > > Even tho it was a round bottom hull it would climb out and sort of plane in > > stronger winds. BTW this boat is looking for a home, it's been stored inside > > an is in excellent condition. Cost a bundle to build but will sell to a proa > > lover at the right price. Get back to me if you want more detail. As a reality check on the recent cheap/expensive debate I would love to know approximately what you mean by "a bundle" for this 18' proa? Of course, materials and labor are one thing and design time is another! > > I actually got a US Patent on the tilting mechanism that I used on the cats. > > It is simple and works well. Anyone interested can find the patent details > > at the PTO (Patent and Trademark Office) website. Finally found it here: Patent #4,653,417 (and 4,537,145) http://www.uspto.gov/ http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/search-adv.htm&r=51&f=G&l=50&d=PALL&s1=white.INZZ.&s2=tilting&co1=AND&p=2&OS=IN/white+AND+tilting&RS=IN/white+AND+tilting I am working now on getting the plugin to view the TIFF file images and will do what I can to convert them to .GIF or .JPG so others can easily see them. > > My website (www.chriswhitedesigns.com) has nothing posted on these > > experimental boats but I do have at least one photo I can e-mail of an 18' > > canting rig cat for those who have interest. YES! Please send me any photos you have including that proa and I will be happy to create a web page for them. I'm sure many folks are interested. regards, Joseph Oster -- http://www.JosephOster.com/chriswhite/ (707) xyz-1234
Subject: Re: [MHml] Twin rigs - added comments From: Joseph Oster <oster_at_wingo.com> Date: Sat, 07 Aug 1999 10:40:04 -0700 To: Tom Speer <tspeer_at_gte.net> CC: MHml <multihulls_at_steamradio.com> Tom Speer wrote: > > > > I'll quote Daniel P. Raymer, "Aircraft Design: A conceptual > > Approach", available from AIAA: <snip> > > 'Hope that helps, It certainly does Tom, thank you! This particular message deserves to be archived somewhere. Very good info and analysis. Joseph Oster -- http://www.JosephOster.com (707) xyz-1234
Subject: Re: [MHml] mostly a proa list... From: Joseph Oster <oster_at_wingo.com> Date: Wed, 11 Aug 1999 07:24:37 -0700 To: Damon Linkous <damon_at_linkpro.net> CC: multihulls_at_steamradio.com Damon Linkous wrote: > > > > This list is mostly a proa list... Actually, the proa snobs (all 27 of us) have created our own private, invitation only mail list where we are currently contemplating our navels in splendid isolation from the world at large. Due to its exclusive nature, I can't tell you how to join. If you haven't been invited, don't worry, you aren't missing anything! Joseph Oster -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] mostly a proa list... From: Joseph Oster <oster_at_wingo.com> Date: Wed, 11 Aug 1999 12:58:51 -0700 To: multihulls_at_steamradio.com Joseph Oster wrote: > > > > Actually, the proa snobs (all 27 of us) have created our own private, invitation only mail > > list where we are currently contemplating our navels in splendid isolation from the world > > at large. Due to its exclusive nature, I can't tell you how to join. If you haven't been > > invited, don't worry, you aren't missing anything! Just to clarify, I didn't create the proa mail list and only learned today that it is by invitation only (which doesn't please me!). I was being sarcastic in the previous post. As far as I'm concerned, everyone is invited but it's not my list. The current topic is a micro proa only eighteen feet long in which I am rapidly losing interest because at this size, I believe a catamaran is better suited. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] mostly a proa list... From: Joseph Oster <oster_at_wingo.com> Date: Wed, 11 Aug 1999 18:53:20 -0700 To: Tom Henry <tomhenry_at_direct-connection.com> CC: multihulls_at_steamradio.com Tom Henry wrote: > > > > I had recently been thinking to myself that the 'proa' threads had pretty > > much died out -- now I can see why -- what a loss. Missing any sincere > > discussion of things proa is a loss IMHO. There are 410 messages recorded on the Proa list in July, 222 so far in August, so yes, alot of traffic has moved elsewhere. > > If there's interest (opinions any/everyone?) in an 'open' proa-specific > > list I'd happy to set one up. Yes! I'd be very much interested in an open proa list. I was thinking along the same lines myself but please go ahead if you have the capability. Some of the proa good old boys and their toys are getting rather stuffy for my taste, especially with the indirect references pretending I don't exist (i.e., "Since someone brought it up" and "no matter what the theoretical advantages of 68-foot long hulls might be"). The current proa list is dominated by concerns which I debated on this list last month, namely low cost having a higher priority than any other consideration. So they are constraining their discussion to the micro proa which, IMO, ignores some of the fundamentals of proa and multihull design in general. I am as interested as anyone else in saving money but refuse to throw away what I've learned in eleven years of studying and sailing proas specifically and "large" multihulls in general. And since I'm not currently building or sailing a proa, it appears I'm not qualified for Craig's proa club anyway. A "small" proa could be fun but not if it's so small the ama can't support my weight! I created a little Javascript "Ideal Boat Hull Calculator" to explore the relationship between length, beam, prismatic coefficient, displacement and minimum wetted surface which has so far been ignored by the proa list, apparently because they are more concerned about the maximum length allowed on a car top in England than designing an optimum modern hull shape: http://www.JosephOster.com/sailing/boathull.html Guy Gibbins wrote: > > > > Perhaps if you cross referenced wing and proa we could identify that elite > > group destined never to get their feet wet. If they ever do build this 18' proa (kind of an undersized, low buoyancy Hobie cat), I predict they will be getting their feet wet all too frequently! That's just one of my complaints. :) And I do go sailing all the time on San Francisco Bay. Cheers, Joseph Oster -- http://www.pacificproa.com/links.html (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Re: biplane wings From: Joseph Oster <oster_at_wingo.com> Date: Thu, 12 Aug 1999 07:03:51 -0700 To: "Metza, John" <John.Metza_at_sheldahl.com> CC: multihulls_at_steamradio.com "Metza, John" wrote: > > > > Snip "one really needs a VPP to be able" > > > > More acronyms I don't understand? Velocity Prediction Program -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Proa design question From: Joseph Oster <oster_at_wingo.com> Date: Fri, 13 Aug 1999 10:39:31 -0700 To: Jeff Gilbert <jgilbert_at_dynamite.com.au> CC: MHml <multihulls_at_steamradio.com> > > Jeff Gilbert wrote: > > > > [Image] Attachments and HTML messages on this mail list are a "No! No!"... > > What factors prevent one from fitting a proa with a conventional rig, > > say Marconi, and sailing it thru normal tacks instead of shunting? > > In other words, its an Atlantic proa on one tack, and Pacific on the other. In brief, a Pacific proa is designed with one short hull that tends to _lift_ instead of being pressed down. This reduces the loads on the cross beams and means the ama hull doesn't have to have as much displacement as would the Atlantic proa configuration (or catamaran) where each hull must be able to support the entire weight of the boat. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: [MHml] Rob Denney's "Harry" From: Joseph Oster <oster_at_wingo.com> Date: Fri, 20 Aug 1999 10:57:30 -0700 To: MHml <multihulls_at_steamradio.com> Rob Denney has supplied me with the text of an article he wrote (including drawings!) for his Pacific proa "Harry". With his permission, I have created a web page here: http://www.pacificproa.com/denney/ Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Rob Denney's "U" From: Joseph Oster <oster_at_wingo.com> Date: Mon, 23 Aug 1999 19:52:00 -0700 To: Robertdesr_at_aol.com CC: multihulls_at_steamradio.com Robertdesr_at_aol.com wrote: > > > > Do your self a favor and read MM artical about "U" and the linked artical > > about "W". How timely! Here it is: http://www.pacificproa.com/denney/u.html Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] U photos From: Joseph Oster <oster_at_wingo.com> Date: Wed, 25 Aug 1999 01:36:10 -0700 To: ROB DENNEY <CARBONDESIGN_at_compuserve.com> CC: multihulls list <multihulls_at_steamradio.com> ROB DENNEY wrote: > > > > There will be some pictures in the next day or so on the U web site which > > show what happenened when enthusiasm got the better of detailed analysis. Photos are on the page now! http://www.pacificproa.com/denney/u.html That 5 meter prototype with ballestron boom is WAY COOL! Killer! regards, Joseph -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] 100ft S&S Killer From: Joseph Oster <oster_at_wingo.com> Date: Thu, 26 Aug 1999 15:46:59 -0700 To: "Metza, John" <John.Metza_at_sheldahl.com> CC: multihulls list <multihulls_at_steamradio.com> "Metza, John" wrote: > > > > Is a 100 foot racing proa possible? ABSOLUTELY YES!!! > > What would it cost? Could one build it for 30K? ABSOLUTELY NOT!!! At this size that wouldn't even buy the rig and sails, let alone the hull structures. If my "64% longer" rule applies, consider the cost to be roughly the same as a 61 foot catamaran (100 / 1.64). That would be on the order of 1/2 to 3/4 million dollars (optimistically), not including the cost of campaigning the boat. By comparison, the 118' LOA trimaran RAVE with 30 meter main hull claims to cost $1.125 million for construction plus $940,000 for fitting out. Total: $2.2 Megabucks! http://www.JosephOster.com/multihulls/edwards/index.html Rob has indeed produced a lot of boat for little money by not counting his labor but to be realistic, one must look at the costs of professional construction, engineering, high performance sails and hardware. I have been racing a couple times recently on an F25C, custom all carbon fiber 25' folding trimaran with radical boomless Randy Smyth sails that reputedly cost around $140,000... That's $5,600/foot and boat costs generally go up exponentially with length. Joseph Oster -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] 100ft S&S Killer From: Joseph Oster <oster_at_wingo.com> Date: Thu, 26 Aug 1999 21:39:45 -0700 To: "Metza, John" <John.Metza_at_sheldahl.com> CC: "'Multihulls Sailing List'" <multihulls_at_steamradio.com> "Metza, John" wrote: > > > > Okay, let me re-phrase my question. Could Rob Denny Build it? Rob will have to answer that himself. I can only go on my own experience hanging around a few multihull projects over the years, usually watching more than working (though I've slathered a good deal of epoxy here and there). The really fast guys like Russ Brown, Lou MacGregor and Marc Ginisty can do a great deal in a relatively short time but you must count labor costs in a project such as this. Here is another example for which I happen to know some numbers. This 37' catamaran was built in "record" time (under a year) for about $45K worth of materials including epoxy, wood, paint, sails, outboard and winches. Mast and boom were built of wood. Displacement was around 8,000 lbs. It was sold as a stripped out bare boat to be finished by the current owner for a little more than $100K and was a fabulous bargain at that price. Most cats near this size are $200K retail or more. http://www.apparition.com/ At that time I thought "Well, if you put the two hulls together transom to transom for one 70' main hull, turned the bridge deck ninety degrees to windward, built a 35' ama and appropriate crossbeams - Voila! You'd have a serious proa at relatively low cost". The reality is that 1) builders like that don't come along very often (so at least double the labor cost!) and 2) costs would also be higher because of the extra hull (ama) and finished accommodation needed for cruising (though not as much for racing, of course). I'd probably want a bigger rig too and better sails... And there are novel issues to sort out on a proa like dual rudders... So I've come to believe that I'd be lucky to build my dream boat cruiser for $250..350K. A 100' proa just can't possibly be built for this price or less, IMHO. Two clich? "Talk is cheap" and "Reality bites!" Using figures for professionally finished boats (even monohulls!) in U.S. dollars is a more realistic way to guess at costs. And for a big project like this, one can't afford to just go out and break things so don't forget the cost of professional engineering by a naval architect: $15K or more. > > I am envisioning a hull that is very narrow with not much freeboard. > > The front 20 feet would be wave piercing. > > Almost like needle. Only as wide and high as it needs to be to be stiff. So are you saying that the front 20 feet (at each end) would not contribute to displacement (only wetted surface area)? Then are you really building a 60' proa with wave piercing extensions at both ends? Hmmmm... > > The sails would not be scaled up accordingly. The sails would be two very > > modest rigs. Proas aren't magic. You still need power if you want to beat S&S. And you need some displacement in that ama for righting moment! For the 21-meter design on my proa page, we used about 1,100 sq. feet of sail area on a 51' mast. Based on LOA to mast height ratio, that would scale to a 73' mast on a 100' proa (though things are rarely that simple). As to dual rigs vs. single, that is another topic... The stability of our design was based on eight tons total displacement (cruising boat!) with 25% (two tons) resting in the ama. Not trying to be a wet blanket here, believe me! I've had these big proa dreams for eleven years now... Just trying to be real. And BTW, for Playstation (105'), the construction costs were about $US4.5 million (before the fire) and the operational budget is $US1.5 million per year!! regards, Joseph -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Harry vs tradition From: Joseph Oster <oster_at_wingo.com> Date: Fri, 27 Aug 1999 08:55:11 -0700 To: ROB DENNEY <CARBONDESIGN_at_compuserve.com> CC: MHml <multihulls_at_steamradio.com> ROB DENNEY wrote: > > > > Joseph, I don't suppose the above could go on your proa links page? No for two reasons: 1) Too much quoting of John Dalziel's article and 2) you haven't convinced me at all. If you want to edit/write a "Case for the Norwood Approach to Pacific Proas" without excessive quoting of Dalziel, I suppose I would consider it... But frankly Rob, I would argue vehemently with your conclusions about weight to windward (and am highly averse to disseminating disinformation!). To me, it's like taking a catamaran which already has more than enough stability and shifting weight to weather while at the same time reducing the length of the hull carrying most of the weight! My own experience doesn't support your conclusions. Norwood didn't convince me either and I actually had a couple conversations with him years ago. The best argument you can make is to sail Harry in a variety of conditions and let us know how it works. regards, Joseph -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] S&S killer From: Joseph Oster <oster_at_wingo.com> Date: Sat, 28 Aug 1999 14:18:37 -0700 To: ROB DENNEY <CARBONDESIGN_at_compuserve.com> CC: multihulls list <multihulls_at_steamradio.com> Well Rob, it appears this thread has rapidly "degenerated into a s**t slinging contest" as you put it off list and this time you have no one else to blame but yourself! I'll try to wade thru this thick pile of "Bunkum" as productively (and briefly!) as I can. Speaking of brevity, it would be polite of you to limit your quotes of previous EMail as much as possible because we all read it the first time. Quoting three paragraphs of Capt. Len Susman, for example, followed only by a brief reply is a waste of bandwidth and disk space for those of us who keep all these EMails. ROB DENNEY wrote: > > > > I [...] would respectfully suggest that this lack of design, racing, > > building and (I suspect), seat of the pants living experience is a poor > > base from which to comment negatively on Johns boat. You don't know me at all Rob, certainly not well enough to judge my experience or qualifications in design, multihull sailing, boat building or "seat of the pants living" (whatever that means). The point I was trying to make is that I have witnessed firsthand enough multihull boat building projects by craftsmen who are far more expert than I to know that thousands of hours typically go into boats only a fraction of the size of this 100' proa. If the boat is intended for offshore use, a certain minimum standard of quality and finish is implied, especially if it is not going to fall apart in one season or less. It is important, I believe, to clarify and even amplify the fact that to build any given boat for substantially less time and money implies a much lower standard of quality, both in materials (including sails, rig and deck hardware) and workmanship, possibly even to the point of being unseaworthy. I cannot accept an argument that says boats are expensive to build only because of incompetent or greedy boatbuilders. If we are going to compare costs, we must compare apples to apples. > > Joseph says > > You really must count labor costs in a project such as this. And Rob replies: > > Bunkum, and Bunkum again! If no one ever does anything new on their own > > without paying professionals to do it, nothing new will ever get done I didn't say it had to be done by professionals, only that "Using figures for professionally finished boats (even monohulls!) in U.S. dollars is a more realistic way to guess at costs". No matter who does the work, the labor time must be included in any cost comparisons, even for do it yourself projects. The simple fact is that most people aren't boat builders and in these cases, the job will very likely take much longer than a professional and probably not be done as well. > > Get your hands sticky on a project or > > two for yourself, you will learn heaps about the art of the possible and > > expand your boating horizons enormously. Thanks man, I've been there and done that more than my modest claims apparently indicate. Enough to know that I far prefer sailing to building. > > Joseph: > > Most cats near this size (37') are $200K retail or more Rob: > > Who gives a rats bum? John wants a boat to go fast, period. This sounds like "Don't confuse me with the facts!" :-) > > standard of finish, building time are all irrelevant. And even if he > > doen't beat S&S, so what? The "so what" is that after considerable effort he will have failed to meet his stated goal! I know it can't be done for $30K but if you are going to lead someone down the garden path, you better at least deliver on performance, even if you break his budget. > > Bet you any money you like he cleans up your dopey friend > > in the $140k Farrier tri. I would be shocked if a decent 100' proa couldn't beat a 25' trimaran but I assure you my friend isn't "dopey" at all. That amount of money on a small boat sounds ridiculous to me too but he can afford it and enjoys regularly beating nearly everyone in the San Francisco Bay Area, mono and multi, regardless of their size or the course. A significant part of the reason (and expense) is the extremely high quality Randy Smyth sails he uses. A similar quality, though larger set of sails would also be appropriate for any high performance proa and that blows the $30K budget away on sails and rig alone. Please save the twin wing sails theory for another thread... > > What does IMHO mean? "In My Humble Opinion" > > What does Hmmm mean? It means I question the logic of only 60' of waterline on a 100' proa with 20' on each end as wave piercing overhang. > > What have you got against long leeward hulls? NOTHING AT ALL!!! I believe that's the only place you need the long hull on a true Pacific proa that routinely carries most or all of the displacement there. My objection is to the idea of carrying the majority of weight on a shorter windward hull as you propose. In these cases, the weather hull will rarely "fly" and should be designed to carry the load gracefully, just as the leeward hull does. That means you really have an Atlantic proa which honestly acknowledges this by having both hulls the same size. Where is the "common sense" in having a shorter hull carrying most of the weight most of the time? > > I would hope that normally it would be the weather hull which flew, > > in which case it would be no worse than a cat flying a hull. With more than 50% of the weight in a weather hull that is only 2/3rds the length of the leeward hull (according to your drawing of Harry), it certainly would be worse than a catamaran, IMHO. This seems clearly self-evident to me but we are both speculating here so again, I look forward to hearing about your actual sailing experiences with Harry. > > The shortness of the windward hull on harry may well be a problem, > > it certainly is on U. Aha! I thought so. That really is the essence of my whole point. If both hulls must be the same length and displacement for this to work, then basically you have built a catamaran or Atlantic proa, regardless of rig location. This defeats the primary advantage of the true Pacific proa (IMO) which is "the longest possible waterline for the least amount of material and weight". Other than being bi-directional, Harry bears little or no resemblance to my definition and analysis of the Pacific proa! Aloha, Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] S&S beater From: Joseph Oster <oster_at_wingo.com> Date: Sat, 28 Aug 1999 17:40:17 -0700 To: "Metza, John" <John.Metza_at_sheldahl.com> CC: multihulls list <multihulls_at_steamradio.com> ROB DENNEY wrote to John Metza: > > > > Don't let the s grind you down. I'll fill in this blank for him as "realists"... :-) Caveat emptor, John! ("let the buyer beware") It was my experiences around actual boat projects that burst my bubble of optimism and hope that big boats might somehow be built "cheaply". It is the same dream that inspired Arthur Piver in the '50s to develop his plywood trimarans. To some extent he succeeded, though the really cheap ones often failed to make it back to the dock! Many others have shared this dream too but there are very good reasons that few, if any, examples exist of large cheap boats. Hint: it's not because I am some kind of kill joy curmudgeon. As Ted pointed out, "the basic problem that you need much greater downwind sail area to achieve good VMG" cannot be ignored. I don't believe wing sails alone can solve it so a screacher or spinnaker will be needed to be competitive. Keep the dream alive (I haven't given up either) but keep your eye on the bottom line. Ask yourself over and over, "Does this idea/proposal really have any advantages over a catamaran?". Joseph -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] S&S killer From: Joseph Oster <oster_at_wingo.com> Date: Sat, 28 Aug 1999 23:42:55 -0700 To: Robertdesr_at_aol.com CC: johndl_at_istal.com, multihulls_at_steamradio.com >> > > > Joseph says >> > > > You really must count labor costs in a project such as this. Robertdesr_at_aol.com wrote: > > > > I don't agree. Are we not talking about if a boat for 30K can beat S&S? and > > if so why should time be in the equation? One can endlessly change the project definition to try and win the debate, of course. So now it is "for $30K worth of materials"? What's next? Don't count the sails and rig? Don't count the design and engineering? No engine? etc. What do you think S&S cost without the labor, design time, etc.? This kind of game is just fudging the numbers and obscuring the real costs involved. Joseph -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] S&S Forever From: Joseph Oster <oster_at_wingo.com> Date: Sun, 29 Aug 1999 20:55:13 -0700 To: "Metza, John" <John.Metza_at_sheldahl.com> CC: multihulls list <multihulls_at_steamradio.com> "Metza, John" wrote: > > > > Just to make sure we are talking apples to apples, my estimate of cost were > > based upon zero for my labor costs. I will conceed that counting my labor > > would blow my budget. and: > > I think a lot of the desputes come from not understanding what the > > other person is really saying. That certainly explains some disputes all right. A moving target is also a difficult thing to hit (or agree upon) so it does help for you to clarify your requirements explicitly and stick with them. Back in July when we first kicked this topic around (before it degenerated into "Fastest boat for $3.95"), you started this thread with your list of criteria on July 8th including the following: 3) 4 Single births (almost nothing else inside the bare hulls) 9) Something that could blow away everything in the Chicago-Mac Race You have now conceded (or clarified) that labor is not included in the $30K which is a MAJOR cost of any boat, especially a one-off non production boat. (Aside: I'd be interested in any authoritative figures about what percentage of cost is normally due to labor? In the example I used, it was more than 50% for a still unfinished boat.) I presume you also don't want to include the design and engineering time in your budget because a naval architect's fee could easily consume half the $30K? Are you backing away now from the Chicago-Mac Race requirement and offshore courses in general? Discussion of a "dragster" for very specific conditions and the following would indicate so to me: > > I know I could kick S&S's stern with my windsurfer in 20 knots of wind > > on any course in the world... <snip> I just want to pull up next to S&S and > > dust him!! I don't want to tack around a course and play games with markers. Could you do the Chicago-Mac Race on a windsurfer? The Cabo Race from L.A.? Even the beach cats on steroids used in the Worrell 1000 stop every night so the crews can sleep on the beach. So if the "appropriate conditions" for this dust off are now very limited please make that very clear too? BTW, here is an interesting discussion of S&S vs. Double Bullet II regarding the Newport-Cabo Race by our own Claas van der Linde on the following page: http://www.webstrand.org/yachts/threads/perf01.htm Somehow this "Fastest boat for $30K" thread (a worthwhile discussion, IMHO) lately became a "100' proa for $30K of materials" which, to me, borders on the absurd! I mentioned that the materials (including sails and 10hp. outboard) for that 37' catamaran cost around $45K. Do you seriously believe that 2/3rds of those materials can somehow be stretched into a 100' proa?? Especially one that really requires two hulls of equal displacement and length? And let's be crystal clear about this dispute between the Norwood/Denney approach to proa design vs. the "big leeward hull, small windward hull" approach used in traditional Pacific proas and best exemplified in modern form by Russ Brown's boats: http://www.pacificproa.com/brown/jzerro10-l.jpg Let there be no misunderstanding on this point: they are fundamentally different animals! I hope that John Dalziel and I have made ourselves clear by now on these differences? The dispute isn't a result of "not understanding what the other person is really saying". It is a matter of believing that the primary reason for going to a Pacific proa is to get maximum waterline length for minimum weight which the Norwood/Denney approach DOES NOT DO. respectfully, Joseph Oster -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] harry vs log boats From: Joseph Oster <oster_at_wingo.com> Date: Mon, 30 Aug 1999 10:46:24 -0700 To: ROB DENNEY <CARBONDESIGN_at_compuserve.com> CC: multihulls list <multihulls_at_steamradio.com> > > Joseph Oster says > > Where is the "common sense" in having a shorter > > hull carrying most of the weight most of the time? ROB DENNEY wrote: > > > > Wrong way round. Make the weather hull comfortable with the weight it > > needs to carry, then make the leeward hull as long as convenient. The "slap, dash, bing, bang, boom" school of naval architecture, eh? > > You need the righting moment. How are you going to get it without > > loading the windward hull? You need a precise amount of righting moment for a given rig and wind conditions and a precise amount of power to drive a given hull shape at a given speed. Cruising catamarans normally have _loads_ of extra righting moment to spare. It makes more sense to me to reduce the size, windage and weight of the weather hull to the minimum actually necessary while extending the length of the leeward (main) hull for higher length/beam ratio and prismatic coefficient (required to compensate for the double ended proa hull which is a distinct departure from most cruising cats that have broad, beamy transoms to reduce pitching and carry the displacement). > > John says: > > And I think it is worth pointing out that your estimate of Harry's weight > > is of indeterminate accuracy since the boat is incomplete. Rob replies: > > Shock horror! 18 lbs difference between predicted and actual. > > Harry may well end up being twice the weight it was when launched (550 > > kgs/1200 lbs was the sum of the components, including the short rigs and > > the accomadation. Say another 10% (?) for errors, 610 kgs (1330 lbs)) "twice the weight", "another 10%"... When you first announced Harry on this list July 9th (seven weeks ago!), you made the following statements: > > I have just finished building a 40' Pacific proa (named Harry) > > not launched yet (waiting for sails and tramp, should be sometime next week) > > it weighs about 1,000 lbs (this is the weight of the components > > Or [for $30K] build a 60 footer which would weigh less than a ton > > and have well over 1,000 sq ' of sail. > > Heck, it may even end up 3 times > > heavier, in which case it may be a failure, and may make a good bonfire. I believe, Rob, it is too much effort to sort out the reality behind the myth, especially when it doesn't bother you at all to make bold statements that you must later retract. I prefer at this time to take your suggestion to save time and bandwidth and wait, instead, for the results of your sea trials and racing endeavors. I enjoy the honesty you have expressed in your Harry and U articles and admire anyone who is actually building proas or, for that matter, multihulls of any kind. regards, Joseph -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Harry vs log boats From: Joseph Oster <oster_at_wingo.com> Date: Tue, 31 Aug 1999 14:42:11 -0700 To: ROB DENNEY <CARBONDESIGN_at_compuserve.com> CC: multihulls list <multihulls_at_steamradio.com> ROB DENNEY wrote: > > > > Harry is an experiment, according to you a totally new kind of boat. Norwood was there long before you with this idea of accommodation and weight to windward with rig on the leeward hull. So I've had ten+ years to analyze and discuss the idea. I have exhausted myself trying to explain what I and others think is wrong with this premise. I did forget to mention one important point though: high performance catamarans (and tris) tend to pitchpole before they roll sideways. The same thing may happen for the Norwood/Denney proa sailed to maximum stability. The true Pacific proa with less weight to weather addresses this problem with the longer leeward hull using the same rig as a catamaran of similar weight. There are some very specific numbers available to support this if you do the math. The only thing totally new to me about Harry is the claim of 1,300 lbs. and $4,000 for a 40' boat! If you really are able to pull this off, it may explain why you want and need extra weight to weather. Any boat where the weight of human crew is a significant percentage of total displacement has fundamentally different design criteria than a more fully loaded cruiser. > > anathema to people who won't try anything new until it has been fully > > tested and everyone has one, but it is pretty normal for an experimental > > craft. Good on ya, mate! Experiment away. I have analyzed this in considerable detail with respect to a cruising proa of 7..8 tons and am confident about the main (leeward) hull being the proper place to carry the majority of the weight. The principals of yacht design still apply, even to proas. It would be prohibitively expensive to build such a large boat with more than 50% displacement to windward and then discover what is wrong with it and start over. Much safer to build a catamaran. Or do the careful analysis first. > > Just for the record, what weight, speed, cost and other criteria would I > > need to achieve for harry for you to to rank it as a success? As a > > breakthrough? As a revolution? No waffling, just the figures. I'll stand up and shout "Bravo!" IF and when you deliver on all your claims. I need to see it to believe it. As to "6% out on an estimate", I've heard numbers between "harry launched, ready to sail weighed 400 kgs" ranging up to 610 kgs. and "it may even end up 3 times heavier". This is far too wide a margin for my money (besides, I'm broke right now anyway). It still might not be the design I would choose for myself if it doesn't work when scaled for all the heavy cruising gear considered normal for full time live aboard comfort (which is one of my goals). No matter how light and spartan one tries to be, there is a certain minimum of gear many people consider necessary for 4..6 crew to travel the world in comfort on a boat. Carrying it on a multihull requires, IMHO, a minimum total displacement (fully loaded, with crew) of around 6..8 tons. Doing it at 20+ knots requires a Pacific proa with 75%..100% displacement on the main (leeward) hull that can routinely lift the ama. > > questions. Most of these are yet to be answered, particularly about > > performance and righting moment. I am reluctant to divulge too many details of our analysis or make unsupported claims... But I'd be very disappointed if the 68' cruising proa can't hit 21 knots in a stiff breeze... The hull centerlines are 25' apart with 25% displacement in the ama. > > Hopefully, you are also stopping your negative campaign on John Metza's > > idea as well? I heartily embrace the topic of "Fastest boat for $30K", even if labor and design/engineering are not included in that figure (deceptive as that is!). Where I have a big problem is the assumption that 1) you can beat Stars and Stripes for this amount, 2) that you can build a 100' proa for this amount or 3) that course conditions and construction quality will be highly constrained to do so. My primary interest is in sturdy boats capable of going offshore, not flimsy day sailers, though I have lately become somewhat intrigued by the design challenge and low cost of very small proas (6..8 meters). > > Signing off a thread when you are wrong is always going to be difficult. I'm not aware of being wrong in anything I've said in this thread. > > will take some photos. If I scan them will you put them on the web? I'll consider it, though my server disk space is limited. One photo is literally equal in file size to five times the text in the Harry article. I would also appreciate more mutual respect and much less hostility and personal attack in this debate! Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: [MHml] modern crab claw From: Joseph Oster <oster_at_wingo.com> Date: Thu, 02 Sep 1999 19:57:06 -0700 To: MHml <multihulls_at_steamradio.com> I'm not endorsing this but... Here are some neat photos of a modern crab claw on a Hobie cat: http://www.hssrig.com/ Too bad there is nothing mentioned about performance. Seems like an ideal test bed for comparison! Joseph -- http://www.pacificproa.com/ (707) xyz-1234 He who brays like a donkey knows not the difference between a silk purse and a sow's ear and isn't listening anyway.
Subject: Re: [MHml] Have a look at the Harry web page From: Joseph Oster <oster_at_wingo.com> Date: Wed, 08 Sep 1999 20:32:02 -0700 To: ROB DENNEY <CARBONDESIGN_at_compuserve.com> (off list) ROB DENNEY wrote: > > > > Have a look at the Harry (linked through Joseph Osters proa page) web page Those pages and links were removed last week within seconds of me reading your comment about my need for more sea miles... I gently tried to warn you twice to be more civil instead of a disrepectful loudmouth! Alas, you earned my contempt Rob... Too bad because proa folk ought to stick together. Joseph Oster -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Harry and U web pages From: Joseph Oster <oster_at_wingo.com> Date: Thu, 09 Sep 1999 20:37:52 -0700 To: ROB DENNEY <CARBONDESIGN_at_compuserve.com> CC: MHml <multihulls_at_steamradio.com> ROB DENNEY wrote: > > > > Presumably the wish to inform people about proas is not as strong as it was > > when he asked if he could turn my articles into web pages. Not so Rob! The pages were removed less than a minute after reading these statements of yours to me last week (9/1): "you need some more sea miles" "And it may sprout wings and fly as well!" "21 knots sounds like an unsupported claim to me." "where the righting moment comes from. Appears there isn't any" And more of the same hee-haw... You just haven't been listening carefully, my man! Had enough of your insults, end of story. Joseph -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Catamarans and The Thomas Crown Affair From: Joseph Oster <oster_at_wingo.com> Date: Thu, 09 Sep 1999 20:47:54 -0700 To: marius <mariusrf_at_bellsouth.net> CC: multihulls_at_steamradio.com marius wrote: > > > > From my limited knowledge it looks like the spectacular > > proa attempts are a thing of the past for most world famous designers, and > > I don't know enough to understand if this fact is market driven YES! > > or based on hard technical facts that didn't quite turn out as expected NO! It just happens that big multihulls of any kind are usually expensive, proas included, so the tried and true cat or tri are the safest bet. Also, it takes a gifted sailor to handle a proa. The guy who financed Newick's CHEERS in 1967..68 was truly a visionary and risk taker! It paid off. (Sorry, his name escapes me at the moment) Joseph -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Capsize prevention From: Joseph Oster <oster_at_wingo.com> Date: Sun, 28 Nov 1999 10:31:35 -0800 To: R Biegler <biegler_at_holyrood.ed.ac.uk> CC: multihulls_at_steamradio.com Robert L. Hobbs wrote: > > >> > > in the first place, but designers would have to get off their >> > > traditional duffs and just do it. One day all boats will be >> > > capsize-proof---why not do it now ? Oh, oh, I hear the >> > > "it-can't-be-done" crowd warming up their keyboards, better get my >> > > anti-flame suit on. LOL To which R Biegler replied: > > If you want flames you have to offer us a more substantial target. Hah, hah! An excellent observation. This emperor wears no clothes! Mr. Hobbs is infamous on this list for his "more creative than thou" remarks like this one. No matter how sincere your discussion (and you have raised some good points), his ultimate refuge is always to insult us as a bunch of uncreative and unreceptive traditionalists. The stubborn facts just get in his way! As to capsize prevention, I believe you are also correct in saying that given the right conditions and "a big enough idiot in charge", any yacht can be flipped over, though unmanned catamarans have survived hurricanes without turning turtle. The issue is two-fold: 1) capsize resistance and 2) capsize recovery. Only monohulls are likely to roll back on their feet after turning 180 degrees. This principle is demonstrated most clearly in oil rig life boats and Coast Guard vessels with huge reserve buoyancy located high above their center of gravity and no stability in the inverted position. Any multihull with these properties is likely to look like a Quonset hut or blimp hanger. The only type of sailing multihull I know of that demonstrates positive righting moment beyond ninety degrees without relying on masthead flotation is the Pacific proa with buoyant leeward "pod". (Surprise, surprise!?) The volume and position of this reserve buoyancy relative to the yacht's center of gravity can produce an extremely large second peak in the stability curve when the angle of heel exceeds thirty degrees or so. As to getting caught with the wind on the wrong side of the boat, the forces will be much smaller unless the sails are designed to be trimmed in that direction (i.e., an AeroRig). The Pacific proa's long waterline relative to its sail area also makes this hull form more resistant to pitchpoling than cats or tris. Sure, huge waves could toss the boat over beyond its ability to recover. My guess is that any multihull declared "capsize-proof" will be a dysfunctional ugly duckling not worthy of the term "sailing yacht". Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Capsize prevention ![Catalacs] From: Joseph Oster <oster_at_wingo.com> Date: Tue, 30 Nov 1999 22:25:50 -0800 To: marcdm_at_wolfenet.com CC: Multihull Group <multihulls_at_steamradio.com> Marc DeMartni wrote: > > > > Friends-here is the challenge: > > > > Come up with something to keep a vessel going to windward which looses > > efficiency quickly as the cat heels so that the boat slips to leeward > > when the windward hull is any significant distance out of the water. Already been done in a way... Russell Brown's proas use a daggerboard in the center of the ama (always the windward hull). When going to weather and you fly the ama to the point that the daggerboard pulls out of the water, there is a slight but noticeable slippage of the main hull to leeward. This tends to right the boat and drop the ama and daggerboard back into the water, giving the helmsman extra feedback and time to react. You can see this ama daggerboard in the first and last photos on the following page: http://www.pacificproa.com/brown/jzerrophotos.html Of course, the Pacific proa is designed to fly a hull more routinely and easily than a catamaran. Joseph Oster -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: [MHml] Super Cat 39 From: Joseph Oster <oster_at_wingo.com> Date: Thu, 27 Jan 2000 17:31:26 -0800 To: MHml <multihulls_at_steamradio.com> FYI - This looks fun!! http://www.acay.com.au/~gonzo/Other.htm Joseph -- http://www.netsyndicate.net http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Fw: Proas for the future!!! From: Joseph Oster <oster_at_wingo.com> Date: Thu, 27 Jan 2000 20:43:05 -0800 To: Gary Lepak <gnjlepak_at_presys.com>, MHml <multihulls_at_steamradio.com> Gary Lepak wrote: > > > > I received this email from Ernst Zemann... Yes, I'd like to see them, but 2 MB???!!! Seems like a lot. Can you put them on an anonymous FTP or regular web server instead of using EMail? Mr. Zeman has a web site and has recently joined the Multihull Web Ring: http://www.multihull.de/zeman/ German language (unfortunately for me!) but a cool looking foil on the leeward side of what appears to be a 10 meter Pacific proa. Joseph -- http://www.netsyndicate.net http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] 1.5 hulls... From: Joseph Oster <oster_at_wingo.com> Date: Mon, 20 Mar 2000 15:49:37 -0800 To: Kiran Pamnany <kp_at_trillium.com> CC: multihulls_at_steamradio.com Kiran Pamnany wrote: > > > > Does anyone know where an English translation of this page > > is (if any)? > > > > http://www.multihull.de/Proa.htm Herr Othmar Karschulin who runs www.multihull.de copied many of those links from my proa links page here: http://www.pacificproa.com/links.html And then he didn't bother to link to it directly! That's also my own personal photo of Russ Brown's Kauri (without any credit given)! http://www.pacificproa.com/brown/ BTW, Russ and I went sailing last week on his Jzerro and _WOW_ was it fast and fun. First time it has actually been sailing in two years. New rig, sails, etc., empty boat, BIG FUN!!! Russ is planning to leave from San Francisco directly to the Marquesas (a three week trip) in early June. http://www.pacificproa.com/brown/jzerrophotos.html Joseph -- http://www.pacificproa.com/ (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] 1.5 hulls... From: Joseph Oster <oster_at_wingo.com> Date: Tue, 21 Mar 2000 12:03:47 -0800 To: Tom <tomhenry_at_direct-connection.com> CC: multihulls_at_steamradio.com Tom wrote: > > > > Pleeeeease tell us _everything_ about the changes to Jzerro's rig! Primarliy related to weight reduction, he sawed off about 16 inches of the mast (at an angle) and added extra material along the luff of the main to make a "square top" out of it. Then he removed unneeded steel hardware, had special rope shrouds made with spliced eyes, re-configured the masthead anchor light and VHF antenna (the windex spins on this antenna!), etc. Besides new sails, I don't even know what all he did. We are going sailing again now!!! Big winds on the S.F. Bay today! Old photo here: http://www.pacificproa.com/brown/jzerro13-l.jpg Joseph -- http://www.JosephOster.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: Re: [MHml] Adrian Thompsons comments From: Joseph Oster <oster_at_wingo.com> Date: Thu, 30 Mar 2000 09:19:38 -0800 To: Gary Pearce <gary_at_steamradio.com> CC: multihulls_at_steamradio.com Adrian Thompson said: > > > > "We need to pump about 70 tonnes of water out of the port float in order to minimise the loads on the rest of the craft. <snip> > > "The hulls needed to be subjected to 70 tonnes of side force to fall off. Is this 70 ton figure a coincidental number or what?? Very possibly what happened here is that a [major] leak developed allowing the hull to flood which tremendously increased the strucural loads. Joseph -- http://www.pacificproa.com (707) xyz-1234 He who asks is a fool for five minutes, but he who does not ask remains a fool forever. - Chinese proverb
Subject: [MHml] Russell Brown arrives Marquesas! From: Joseph Oster <oster_at_wingo.com> Date: Fri, 07 Jul 2000 10:51:27 -0700 To: MHml <multihulls_at_steamradio.com>, BAMA ML <bama_at_tango.rahul.net> FYI, I received a call yesterday from Russell Brown in Nuku Hiva, Marquesas, where he and Steve Callahan arrived safely last week after a twenty day passage from San Francisco! http://www.pacificproa.com/brown/jzerrophotos.html Joseph Oster -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 home: (707) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Re: Evan's spreadsheet From: Joseph Oster <oster_at_wingo.com> Date: Sun, 10 Sep 2000 18:18:55 -0700 To: CaptRon <captron_at_tampabay.rr.com> CC: multihulls_at_steamradio.com CaptRon wrote: > > Like I tried to express one other time, I get tired of making all of my > > equipment decisions based on weight. At some size of boat all of these fixed > > weight things become a small enough part of the total payload that weight > > oriented decisions have less importance... that's all .... Precisely correct! That's exactly the reasoning I followed twelve years ago when deciding on a 21 meter Pacific proa, equivalent in displacement to a 42 foot catamaran (7 or 8 tons). There is a certain amount of stuff necessary for truly comfortable full time live aboard cruising. These things are pretty much the same whether you have 2, 4 or 6 people aboard. Having been spoiled with Moxie's superb performance (50' Newick trimaran, 5.5 tons), the "large" proa seems to me the best solution for both comfort AND speed. Not changing the subject here! Just in agreement with reasonable minimum displacement. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 home: (650) xyz-1234 http://www.pacificproa.com/
Subject: Re: [MHml] Re: Packet Cats From: Joseph Oster <oster_at_wingo.com> Date: Mon, 11 Sep 2000 10:35:38 -0700 To: KISSCOOK_at_aol.com CC: multihulls_at_steamradio.com, Rob and Sue Linehan <rslinehan_at_earthlink.net> KISSCOOK_at_aol.com wrote: > > Rob, > > My very first piece of advice is to ask people who actually know something > > about the boats. In other words, people who have sailed them, surveyed them, > > lived on them, used them etc. It is sometimes the case that people who have high praise for their own decision have virtually no experience with anything else! Asking these "experts" (i.e., a packet cat owner) will tell you nothing about the superior alternatives. My advice to Rob Linehan is to keep looking for a real multihull. > > The packet cat was designed for a specific purpose, to provide aging cruisers > > a viable alternative to a trawler. > > <snip> > > Keep in mind this is NOT an offshore boat. > > <snip> > > Please, let us compare apples to apples. Exactly. This is a multihull forum, not a trawler forum! :-) Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 home: (650) xyz-1234 http://www.pacificproa.com/
Subject: [MHml] sail cat From: Joseph Oster <oster_at_wingo.com> Date: Mon, 11 Sep 2000 20:05:05 -0700 To: MhMl <multihulls_at_steamradio.com> This discussion of "sail cat" brings up an old Jonathan Winters (comedian) story I was reminded of recently when I accidentally typed the following URL: http://www.sailcat.com/ This guy's version of the story is as follows: "It seems that in the summertime, when felines are on the prowl, that the opposite side of a highway beckons so irresistibly that they tempt fate in a mad dash, and are often unsuccessful in avoiding the inevitable encounter with a speeding automobile. It is under these circumstances, with cars passing over the hapless critter who has passed on, in the warmth of summer, that a flat, dry roundish disk of sorts is formed. As a matter of fact, this can actually be picked up, flung by hand and skimmed like a Frisbee. That's called a sailcat." http://www.sailcat.com/meetsailcat.htm And now we resume our regular programming... ;-) Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 home: (650) xyz-1234 http://www.pacificproa.com/
Subject: Re: Kites[MHml] From: Joseph Oster <oster_at_wingo.com> Date: Wed, 13 Sep 2000 08:18:05 -0700 To: ted LAMONT <tlamont_at_central.murdoch.edu.au>, MhMl <multihulls_at_steamradio.com> ted LAMONT wrote: > > > > Joseph Oster will probably agree that they have potential on proas as well. They certainly do! :-) I had the honor and pleasure of sailing with Dave on his kite proa last spring; it was a huge kick! Congratulations Dave on flying the BIG kite!! > > An Atlantic proa would be rigged to give a lifting force on the float Definitions get a little fuzzy when it comes to kite proas since the small float is to leeward (as you describe) instead of to weather as in a "normal" Pacific proa. Dave has earned the right to call it whatever he wants though, IMHO. Cheers, Joseph -- http://www.shutterfly.com Work: (650) xyz-1234 Cell: (650) xyz-1234 Home: (650) xyz-1234 http://www.pacificproa.com/
Subject: [MHml] 34' Newick proa From: Joseph Oster <oster_at_wingo.com> Date: Tue, 26 Sep 2000 11:48:00 -0700 To: "William J. Burke" <wburke_at_worldpath.net> CC: MhMl <multihulls_at_steamradio.com> > > could let me know the url where the info will be, I can pass it on to people > > who have contacted me off-list (23 inquiries so far...) I'm busy at work at the moment but created a quickie page with photo here: http://dicknewickboats.com/proa.html Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 home: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] proas From: Joseph Oster <oster_at_wingo.com> Date: Sun, 29 Oct 2000 12:36:52 -0800 To: Jake Bishop <jakebishop_at_monkeybrains.net> CC: multihulls_at_steamradio.com Jake Bishop wrote: > > > > I read recently that Russ Brown and Steve Calahan sailed from San Francisco to > > Nuka Hiva in 20 days in Russ's most recent boat, Jzerro.Anybody heard anything > > else about this trip?. Just got this email from him on Friday: "I guess you heard I'm going to be a little late, didn't like Fiji for leaving the boat. I just had a sobering sail to New Caledonia, really heavy reaching conditions and really frightening seas. I had to really push the boat hard and it did ok. Better than me. I'll be back mid November. leaving soon for Aus. Lots to tell you. take care, Russell" This and one phone call when he arrived in the Marquesas is all I've heard from him; long distance is costly. Guy Gibbins wrote: > > Maybe I shouldn't have used the "ugly" word but I wasn't being bigoted or > > xenophobic. To produce a commercially viable proa the asymmetric look is a > > problem. Proas _ARE_ symmetrical, it's just that the plane of symmetry is perpendicular to the direction of the boat! In other words, stand in the middle of the weather hull (where the wind comes from) and look to leeward... Both ends are indentical! and: > > However while the proanauts point to Harry as the dawn of > > the age of the proa... HAH-HAH, hee-hee, ho-ho!! No, I don't think so, not by a LONG shot. Russ Brown gets credit for that, even though Multihulls Magazine rudely omitted mentioning him in their proa issue. > > I think Harry illustrates just how much how far behind proas are. Agree with you there. ;-) and: > > Somehow I suspect Mr.Buckminster Fuller would be bugger all use on a boat... Actually, he loved to sail his own monohull! Joseph -- http://www.shutterfly.com Work: (650) xyz-1234 Cell: (650) xyz-1234 Home: (650) xyz-1234 http://www.pacificproa.com/
Subject: [MHml] Russell Brown in Australia From: Joseph Oster <oster_at_wingo.com> Date: Mon, 30 Oct 2000 21:56:45 -0800 To: MHml <multihulls_at_steamradio.com> >From Russell: "Trying to find a place to leave the boat there, do you know any proa enthusiasts in the Brisbane , Bundaburg area? I'd like to find someplace besides an expensive boatyard to keep the boat. any ideas? New Caledonia is really cool. talk to you soon, Russell" I have no idea yet how long he plans to leave the boat but if anyone can help him out, please send me contact information and I'll forward it to him. Cheers, Joseph -- http://www.shutterfly.com Work: (650) xyz-1234 Cell: (650) xyz-1234 Home: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Model boat competition From: Joseph Oster <oster_at_wingo.com> Date: Thu, 25 Jan 2001 07:28:21 -0800 To: multihulls_at_steamradio.com Rob Denney wrote: > > > > (such as Harry, my 12m proa) is less effort to shunt/tack than virtually > > any other multi. WRONG again dude!!! At the very least, a proa requires sheeting the main around from one end of the boat to the other. Balanced rig or not, this is a string that doesn't need to be touched at all when tacking a trimaran or cat (which require only movement of the tiller). This makes the proa more complicated to tack, not less, which will surely become obvious in a radio controlled model. Joseph -- http://www.shutterfly.com Work: (650) xyz-1234 Cell: (650) xyz-1234 http://www.JosephOster.com
Subject: [MHml] Russell Brown in Cruising World From: Joseph Oster <oster_at_wingo.com> Date: Tue, 20 Feb 2001 21:05:33 -0800 To: MHml <multihulls_at_steamradio.com> I haven't seen it myself yet but got word today that the latest issue of Cruising World has a piece on Russell Brown sailing his proa to Tahiti! Joseph -- http://www.shutterfly.com Work: (650) xyz-1234 Cell: (650) xyz-1234 http://www.JosephOster.com
Subject: [MHml] Russell Brown on COVER of Crusing World! From: Joseph Oster <oster_at_wingo.com> Date: Wed, 21 Feb 2001 14:24:52 -0800 To: MhMl <multihulls_at_steamradio.com> Just found a copy myself of the March 2001 issue of Cruising World; Russell Brown's proa JZERRO is on the _COVER_ of the magazine (sailing off Bora-Bora) with an eight page article by Steve Callahan who crewed on the boat for this trip! Great photos inside too. WAY COOL!!! Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: [MHml] Jzero of Polygor From: Joseph Oster <oster_at_wingo.com> Date: Fri, 09 Mar 2001 09:48:55 -0800 To: MhMl <multihulls_at_steamradio.com> I've been contacted by a guy who has some incredibly good photos of Russell Brown's first proa, the original thirty foot "Jzero of Polygor". Check this out! http://www.zahnisers.com/zcrb/jzero/ Also featured here: http://www.pacificproa.com/brown/jzero78.html regards, Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: [MHml] advantages and optimum uses for proas? From: Joseph Oster <oster_at_wingo.com> Date: Wed, 23 May 2001 17:28:42 -0700 To: multihulls_at_steamradio.com GABarker_at_aol.com wrote: > > > > I have a question, and no disrespect is intended towards those with fewer > > hulls: What are the advantages and optimum uses for proas? and Bill Gibbs replied: > > > > You'd have good luck taking this question to the Proa list. Ahem...(!) A proa _IS_ a multihull Bill. ;-) This topic has been discussed heavily in the past but in my view, the essential advantage of the Pacific proa (lifting small hull to windward) is this: It gives you the longest possible waterline for any given weight (which often is proportional to cost!). There are many elements that make a Pacific proa work well but that's the essence of it; the speed and other advantages follow. > > with is Russell Brown's, but sitting out on that platform on the outrigger > > beams at high speed during a blue water crossing would not be my idea of fun The cockpit is at the very center of the boat, not out on the ama. Because you are sitting almost precisely at the center of gravity (at the base of the mast), the motion is very still at that point. http://www.pacificproa.com/brown/kauari-helm-l.jpg http://www.pacificproa.com/brown/ It is extremely comfortable. Joseph -- http://www.shutterfly.com/proa/ work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] advantages and optimum uses for proas? From: Joseph Oster <oster_at_wingo.com> Date: Mon, 28 May 2001 10:00:20 -0700 To: multihulls_at_steamradio.com GABarker_at_aol.com wrote: > > > > I've seen a photo of two people on a bench placed midway out on the beams > > blasting along at about 25 knots in the San Francisco Bay, spray flying. That was me and Dave Culp! http://groups.yahoo.com/group/proa_file/files/jzerrolg.jpg That "couch" we are sitting on is for passengers, the cockpit where Russell is working the boat is directly to leeward of that, on the weather side of the main hull. It is the _ONLY_ place from which this boat is driven; the photos on the cover Cruising World and accompanying article shows it a little better. All halyards, sheets, uphauls/downhauls and steering linkages lead to this small cockpit, designed for singlehanding. > > But very economical and efficient to what purpose. I understand they were > > and are used for interisland transportation, but the above answer says to me, > > "fast at low cost." That's fine, I'm just trying to understand. It is a widespread opinion (which I share) that a long waterline on any boat has _MANY_ advantages including speed, safety and comfort. The drawbacks, of course, are higher initial cost and finding dock space. While the proa form doesn't solve the latter, it is the longest boat for the least money. Alas, Rob Denney does a disservice to history and truth by calling his lopsided catamaran a proa... He has missed many key features of the Pacific proa, most important of which is that the main hull to leeward carries the load, not the windward hull. This is fundamental to everything else including reduced mass of connecting structure, reduced mass and volume of weather hull and extra speed possible by lifting the weather hull free of the water. Indeed, it is crazy to claim Pacific proa advantages for his ugly and dysfunctional catamaran. He routinely distorts the proa image with statements like this: Rob Denney wrote: > > > > First and foremost is the heeling load, caused by having the rig > > upwind of the lee hull. Utter nonsense! Mr. Denney is clueless about the physics. The "tipping moment" caused by the center of effort of the sail is not affected by moving the mast to leeward (or to weather). If you take a catamaran and move it's mast to either hull, the righting moment remains the same. It may not be intuitively obvious but I assure you that a naval architect will confirm this fact. Debate has been pointless so I'll conclude simply by saying this: Take a look at the cover of Cruising World, March 2001. If that photo of Russ Brown's JZERRO gently flying a hull near Bora-Bora doesn't convince you which is the correct and true form of a Pacific proa, then just stick with a conventional catamaran! Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.pacificproa.com/
Subject: Re: [MHml] advantages and optimum uses for proas? From: Joseph Oster <oster_at_wingo.com> Date: Mon, 28 May 2001 12:14:05 -0700 To: multihulls_at_steamradio.com Tom Speer wrote: > > > > Take a look at the rig heights compared to the boat lengths of typical proa > > and cat/tri designs. A typical tri will have a mast that is half again as > > long as the boat. I don't think you see many proa masts that are this long. > > If there's a difference in bow burying, I think this is where you'll find > > it. Thank you sir for such a precise and excellent analysis!! Correct on all points, according to my own research (and explained far better than I could!). This issue of the large hull to leeward on a Pacific proa seems to deserve a little more discussion... Keeping in mind, as you point out, that total heeling moment is limited by the center of gravity being closer to the leeward hull (dictating shorter masts!), many people don't seem to appreciate the dynamics of weight transfer between the hulls as the moment of maximum stability is reached. That point happens in any two (or three) hulled vessel when the weather hull flies, leaving only the single leeward hull in the water to carry all the displacement of the vessel plus any vertical component of sail force. In a catamaran, this is a change from 50% displacement in each hull to 100% displacement in the leeward hull or, from the point of view of that leeward hull, 200% of its at-rest displacement. The Pacific proa starts with only 25% displacement to weather so when that hull flies, the main hull is carrying only 133% of its at-rest displacement instead of 200% for catamarans (or much more for "Atlantic" style proas). Relatively speaking, not such a "big deal", making it safe and routine. With the center of gravity and center of buoyancy relatively close together in the Pacific proa (large hull to leeward), the motion feels lighter and quicker somehow, producing less stress on hull connectives? Imagine a hand held rod, grasped in the middle, with a wooden ball on each end. Twist quickly. Now imagine the same rod with a single wooden ball in the middle, equal to the combined mass of both balls in the earlier experiment; again, twist quickly. Is "angular momentum" the correct term? In any case, the early builders of these craft discovered all these things by simple experiment and pushing their limited building materials to their maximum breaking strengths. With limited resources, they could build a bigger, better boat when only one big hull was needed to carry the full load. Their elegant logic still applies! Cheers, Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] advantages and optimum uses for proas? From: Joseph Oster <oster_at_wingo.com> Date: Mon, 28 May 2001 13:09:46 -0700 To: multihulls_at_steamradio.com Roy Mills wrote: > > > > and obviously you disagree strongly with Mr Norwood who feels that > > Rob's approach gets the best of both worlds as it were. Yes. > > Robs boat sails both ways, therefore is it not by our definition a proa? Yes. Just definitely NOT a "Pacific proa" as he routinely claims. Dick Newick (not Joseph Norwood nor Rob Denney) developed the alternate proa form (ama to leeward and all weight to weather), to near perfection in 1968 with the graceful and effective "Cheers": http://dicknewickboats.com/cheers.html I have seen no improvements to the "Atlantic" style proa by anyone since then. It is certainly not an improvement to shorten the weather hull which is carrying most of the weight in light air! > > I don't see that such a variation should be so roundly criticised. It's not the variation or experiment I object to, it's the dubious claims and misrepresentations I keep hearing, along with persistent, self-serving and at times belligerent attempts to redefine what a Pacific proa is all about. Past efforts at civilized debate with Mr. Denney on this forum quickly dissolved into hostile nonsense, ridiculous claims, resistance to explanation, baseless attacks and insults. So in general I don't bother to engage anymore, except to occasionally clarify the distinct characteristics that make a proa a "Pacific proa". Calling a boat with 50% or more displacement to weather a "Pacific proa" and claiming many of the same advantages is a gross mis-characterization that deeply bothers me, OK? Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.pacificproa.com/
Subject: Re: [MHml] Re: advantages and optimum uses for proas? (Joseph Oster) From: Joseph Oster <oster_at_wingo.com> Date: Mon, 28 May 2001 21:43:26 -0700 To: multihulls_at_steamradio.com Rick Anderson wrote: > > > > I would prefer that Oyster find another > > vehicle for his comments about Mr Denney .. The name is Oster, not Oyster. If that's an attempt at humor, I am not amused; if it is a deliberate put down, fine, so be it... Don't turn around then and ask questions of me. Joseph Oster -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.pacificproa.com/
Subject: Re: [MHml] advantages and optimum uses for proas? From: Joseph Oster <oster_at_wingo.com> Date: Tue, 29 May 2001 08:37:56 -0700 To: multihulls_at_steamradio.com GABarker_at_aol.com wrote: > > > > It seems to me that the Pacific Proas are kind of like monohulls in that a > > mass (the ama) is preventing overturning. It is just positioned differently > > (and probably more effectively pound for pound) than the lead in a monohull's > > belly. Very true! That "ballast" is just floating out to one side instead of hanging straight down. And of course, it's not simply lead out there but arranging the weight and contents of the structure to rest on both hulls. Don't forget the buoyant leeward pod on the Russ Brown style proa; as it is crucial to prevent overturning to leeward in a knockdown. Cheers! ;-) Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.pacificproa.com/
Subject: Re: [MHml] advantages and optimum uses for proas? From: Joseph Oster <oster_at_wingo.com> Date: Tue, 29 May 2001 11:05:14 -0700 To: multihulls_at_steamradio.com Roy Mills wrote: > > > > It seems then that your concern is essentially one of semantics <snip> > > Since mast to leeward or mast to windward has been established as a > > major defining factor, associated with Pacific and Atlantic respectively Sorry, no, that is not a defining factor at all. Once you put 50% or more displacement in the weather hull, the dynamics of the boat are totally different in _every_ way. It matters very little where you put the rig (though I agree that slightly to weather of the leeward hull is an excellent place!), boats with such drastically different weight distributions as found in the "Pacific proa" vs. "Atlantic proa" or catamaran are totally different animals in terms of hull sizes, wetted surface area, and a host of other factors. Stuart Bloom has mentioned "The ratio of lateral stability against longitudinal stability" which is indeed very important. Because of the reduced initial stability of the Pacific proa (as I have described it), that ratio is low; the mast is short relative to the boat's length which tends to increase resistance to pitch poling. To make up for potentially limited performance (reduced mast height), Russell can sail JZERRO "hot" with high performance gear like full batten square top mainsail and screacher on bowsprit pole. When you provide excessive lateral stability (ultra wide catamaran or more than 50% displacement to weather) and then push those hulls hard with a tall mast, you are far more "on the edge" than a conservatively rigged Pacific proa lifting it's small, light hull and driving a single powerful hull thru the water. I consider this a very important distinction, not a minor quibbling difference of semantics. I haven't seen any record of ancient Pacific islanders building proas with the heavy hull to windward. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] advantages and optimum uses for proas? From: Joseph Oster <oster_at_wingo.com> Date: Fri, 01 Jun 2001 15:10:05 -0700 To: multihulls_at_steamradio.com I typically skip posts from Rob Denney so didn't see this one (Wed, 30 May 2001 10:35:12 +0800) until scrolling thru the messages on the proa list... Sigh... An example of what I referred to earlier as "hostile nonsense"... First, I created some confusion myself when I said: > > Alas, Rob Denney does a disservice to history and truth by calling his > > lopsided catamaran a proa I meant to say "Pacific proa". For anyone who really cares about proa issues, the distinction between heavy hull to weather vs. heavy hull to leeward is not merely semantic quibbling, it is night and day, apples and oranges. The differences are so drastic that it is ludicrous to be making the same claims for the "Atlantic" vs. "Pacific" proa style. Mr. Denney continues to muddy the water by referring to Harry as a Pacific proa and making claims that really only apply when you have a small hull to weather, not a heavy one. Rob Denney wrote: > > > > Don't forget the "fundamentals" of many crew running back and forth to keep > > the traditional boat upright, regular dunkings or slow sailing when they > > don't, the clumsy, inefficient steering oar, the need to move the rig from > > end to end each time you shunt, the rudimentary accommodation, lack of > > upwind ability and the dearth of choice in building materials. That has nothing at all to do with a modern Pacific proa. > > The reduced connecting structure required on a traditional proa is > > nonsense. Whether the righting moment comes from accommodation to windward > > (Harry), people to windward (traditional) or water ballast to windward > > (Russ' boats), the load on the connecting structure, for a given weight a > > given distance to windward is the same. Sorry, not so at all. But math doesn't seem to be your strong suit. > > Of course, but read it again, please. I was referring to the load which > > depresses the leeward bow, as per Greg's question. Ok, I'll read it again, from your post of Mon, 28 May 2001 17:20:44 +0800: "First and foremost is the heeling load, caused by having the rig upwind of the lee hull." Says to me the same thing it did the first time, that you believed moving the rig to leeward would reduce your heeling load. You were wrong. > > there is nowhere dry above decks on Jzerro in a > > breeze, ballast needs to be pumped frequently, shunting is complicated, the > > boat is generally cruised underpowered and cruising downwind the main has > > to be removed to stop the mast falling down in an accidental gybe. Again, utter nonsense. You have no idea what you are talking about. > > (re: Cheers) If this is your idea > > of "near perfection", it is no wonder that you think traditional Pac proas > > cannot be improved upon. Hah, hah. Calling me a traditionalist now, eh? That's funny. As to Cheers, what made it so perfect in my mind is that the hulls had completely separate purposes. Like a trimaran, that leeward hull was designed to immerse without any obstructions. Once you start moving the rig over there, you need something to keep it up out of the water and hopefully some deck space to walk on while handling the sails. Weight gets shifted to leeward and the fully immersible leeward hull is lost. > > Enough is enough. That's for damn sure! > > Also tell us why and how you (who as far as I know, > > have never built a decent sized proa, and whose total experience of the > > type is as a passenger on a day sail on SF bay plus some pretty pictures > > and numbers on your web site) get the arrogance to defend or define the > > term "Pacific" proa? As before, once again you insult my sailing credentials with no knowledge whatsoever about me... You are a total idiot Mr. Denney, resorting again to fabrications and baseless insults. > > PS For those who are surprised by Joe's and my intemperate tone, some > > history. We had a discussion on the proa list a while ago, in which Joe > > increasingly desperately tried to prove that a Jzerro type proa (which he > > has been unsuccessfully trying to sell, but hasn't the ???? to build for > > himself) was superior to a Harry type. I am not selling anything. Whatever business plans I had in mind five years ago when I put those pages up have "changed"... I don't even answer proa inquires anymore, I have never tried to take money from anyone. My personal dream boat will cost about the same as a modern 42' catamaran and until I have the money, I'll continue to refine my own plans and share my knowledge freely. > > Joe was more than happy to feature harry on his web page as a Pacific > > proa, until he decided that I (not Harry) was belligerent, at which time he > > removed it. Your mis-statements are so boring. I created and hosted pages of Harry in the spirit of proa fellowship but pointed out immediately in my first correspondence to you that it was really an "Atlantic" proa, not a "Pacific" proa. I'll look it up if I must but please, the difference has been obvious to me all along. Joseph -- http://www.shutterfly.com Work: (650) xyz-1234 Cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] HEY, IDIOT! From: Joseph Oster <oster_at_wingo.com> Date: Sat, 02 Jun 2001 08:25:37 -0700 To: multihulls_at_steamradio.com Rob Denney wrote: > > > > assume he agrees that it fulfills it's design functions, and I thank > > him for this back handed endorsement. Faulty reasoning like this is contributing to your self delusion. >> > >That has nothing at all to do with a modern Pacific proa. > > > > Any more than has the percentage of overall weight in the weather hull! It is you, fool, who have refused to understand and acknowledge the benefits of a smaller, lighter hull to weather, despite numerous detailed, well reasoned discussions on the subject. > > Which part of the maths in "...the load on the connecting structure, for a > > given weight a given distance to windward is the same" are you struggling > > with? All the forces at work in lifting a weather hull which is only 25% of total displacement vs. "lifting" a weather hull which is 75%..90% of total displacement are well beyond the capability for analysis (or lack thereof) that you have shown on this list. > > As before, once again you refuse to spell out what your credentials are. Many people on this list know far more than you do about my sailing experience and "credentials" because the subject has come up in the context of friendly discussions. The point here is that for you to attack me on that basis without any such knowledge and totally fabricate my proa and/or sailing experience makes you a desperate liar Mr. Denney. Joseph Oster -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.pacificproa.com/
Subject: [MHml] Re: Proa Classification From: Joseph Oster <oster_at_wingo.com> Date: Sat, 02 Jun 2001 17:44:07 -0700 To: multihulls_at_steamradio.com Assuming we are talking about cruising proas large enough that crew weight is 20% or less of total displacement(?)... (not beach proas like Tiny Dancer...) Do you make no distinction, Ted, between proas with less than 50% of weight in the weather hull vs. those with more than 50%? I am surprised to be apparently alone in considering this such a vital distinction, far more critical than rig location. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Re: Proa Classification From: Joseph Oster <oster_at_wingo.com> Date: Sun, 03 Jun 2001 12:14:02 -0700 To: multihulls_at_steamradio.com Brian Southwood wrote: > > > > weight distribution. In the long run terminology in the English based languages > > is determined by usage. At present the balance seems to base the distinction > > between Atlantic and Pacific proas on rig position. > > Cheers, Until Newick's proa Cheers came along 33 years ago, all proas were Pacific proas... And despite the obscure Fijian "Ndrua" mentioned by Michael Schacht, the common notion of a proa was an "outrigger canoe" with the small heavy log to weather, main hull to leeward. For the most part, these were the only proas that anyone knew about since Captain Cook's day. http://www.pacificproa.com/flyproa.html The term "Atlantic proa" was coined to distinguish the fact that Cheers carried her ama to leeward and main hull (which also happened to carry the rig) to weather. The fact that more than 50% of total displacement was carried in the weather hull instead of having the "small heavy log to weather" changed everything. For one thing, both hulls tend to become the same length because no matter how you slice it, the leeward hull still carries the load when pressed. So the principal advantage claimed by the Pacific proa (longest possible water line for least amount of weight) is immediately compromised and invalid for the Atlantic proa due to a) both hulls having similar length and volume (below the waterline) and b) a heavier connecting structure required. Except for the accommodation and extra weight being concentrated in the weather hull, such a boat is in fact very similar in structure to a catamaran and must therefore have similar length/weight ratios, decidedly lower than a Pacific proa assuming similar construction methods and the same total weight. Total wetted surface area of the immersed hulls under various conditions will also differ widely between a Pacific and Atlantic proa or catamaran (the Pacific proa being the least). The other thing that happens is that the lateral stability, which is already quite high for beamy modern catamarans, increases even more in relation to length, making pitchpole a greater danger unless reefed. These and other distinctions due to weight placement are the most significant differences between traditional/modern Pacific proas and the Atlantic style pioneered by Nick Newick; they have nothing to do with the location of the rig. http://www.pacificproa.com/johndalziel/ The Norwood/Denney approach of keeping the heavier hull to weather while moving the rig to the leeward hull does not change these weight dynamics at all except to distribute the weight more evenly between the hulls than the Cheers approach does. Believe me, I am all in favor of "To each, his own". If people want to build proas that other way, cool, good luck, I've always been open and honest with all the information I know on the subject. Knowing Harry wasn't a Pacific proa as claimed didn't stop me from creating and hosting web pages for it. Besides the personal insults(!), what has disturbed me about this Denney/Harry business is that for 33 years now, "Pacific proa" has meant "flying proa" or "small heavy log to weather". While there is nothing sacred about percentages, the range of 10% to 33% total displacement in the weather hull covers the genre pretty well. There are a set of distinct sailing attributes that result from this configuration that cannot be claimed by boats with 50% or more total displacement in the weather hull. Period. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Re: Proa Classification From: Joseph Oster <oster_at_wingo.com> Date: Sun, 03 Jun 2001 14:56:23 -0700 To: multihulls_at_steamradio.com P.S. Joseph Oster wrote: > > > > Nick Newick Uh... Dick Newick! And according to a fascinating "rant" on Proa Etymology by Michael Schacht (great web site!) where he refers to that Fijian "Ndrua": http://www.schachtdesign.com/proafile/volume_1/rant.html "According to anthropologists, proas are always shunting single outriggers with unequal length hulls. Accordingly, Newick's Cheers would not qualify. Cheers would be a shunting catamaran, since it has two equal hulls. There are examples of shunting catamarans in the Pacific, so don't laugh." and: "Length is the criteria. Catamarans, or more correctly, double canoes, have twin equal length hulls. And they don't even need to be perfectly equal to qualify. The huge Fijian Ndrua is called a double canoe, yet it has fairly unequal sized hulls. It does perch the cabin structure more in the bilateral centerline of the boat than over to one side or another, and it shunts to come about." According to that, the term "proa" is even more exclusive than I thought! It would rule out the "shunting catamaran" with nearly equal length hulls (due, of course, to 50% or more displacement in the weather hull and the appropriate prismatic shape required to carry that load). Strictly speaking then, proa and "Pacific proa" are redundant, since they both refer exclusively to boats with a significantly shorter (smaller) hull to weather. And the "heavy hull to weather" class are termed "shunting catamarans" (as I had always thought of them!) or "Ndrua", though I have and will always respectfully use the term "Atlantic proa" as well. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Re: Proa Classification From: Joseph Oster <oster_at_wingo.com> Date: Mon, 04 Jun 2001 11:55:21 -0700 To: multihulls_at_steamradio.com Dave Culp wrote: > > > > unfortunately, it becomes a matter of degree, and not of > > specification. 25%, 33%, 50%, even more; precisely where does the > > real, fundamental sailing and construction difference become > > significant? There is a "quantum event" that occurs when 50% displacement in each hull is reached... At that point, the path of optimization leads quickly to a bow and stern on the boat, giving up shunting, using wide aft sections to carry larger loads, shifting mast position from center of boat, etc. The conventional modern catamaran! Other aspects/advantages of Pacific proas have been mentioned (and you know them well) that cease to be true when displacement in the weather hull is equal to or greater than displacement in the leeward hull. This is the key point!! If you believe those things are true, how can it also be true that "50%, even more" to weather is possible while retaining those same advantageous characteristics gained by having that smaller hull to weather? It doesn't make any sense. Also, let's not forget another key criteria I mentioned which minimizes the effect of shiftable ballast and super light (flimsy) construction methods: Assume we are talking about cruising proas large enough that crew weight is approximately 20% or less of total displacement, as with any typical mono or multihull longer than thirty feet or so. That means a boat around 3,000 lbs. or more, without crew. Cheers, Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Joe's credentials. From: Joseph Oster <oster_at_wingo.com> Date: Mon, 04 Jun 2001 19:50:39 -0700 To: multihulls_at_steamradio.com nudd wrote: > > > > Obviously Joe is reluctant to "blow his own trumpet". This is all quite absurd. In the first place, totally false accusations were made up out of thin air regarding my verifiable proa sailing experience... How absurd is that?! In the second place, do you think every Whitbread sailor who has circled the globe is qualified to design weird multihull configurations like Pacific and Atlantic proas? Ted wasn't kidding when he said it stretches the brains of qualified naval architects who have marvelous ways of quantifying these things... As to my sailing experience, I re-started as an adult in 1985 with a friend in a Catalina 23 (monohull) on Vineyard Sound out of Lake Tashmoo, Martha's Vineyard. I met Russell Brown in the fall of that year while sitting on the beach behind the health food store, between the famous Black Dog restaurant and the Gannon & Benjamin Marine Railway. Russell was hauling Kauri on the beach for the winter, I helped him a little and got a close look, including inside. We were still sailing the Catalina frequently in the spring of 1986 when one day a magnificent 50' trimaran blocked access to our dock. Moxie had just arrived from winter haulout in Maine and suffered damage to her starboard ama (old Navy wound) so Dick Newick had lifted the damaged ama up onto the dock and was doing a major repair. We got rides on Kauri once in awhile that summer and then in the fall of 1986 I crewed on a 41 foot, 45 ton(!!) "Pinky" schooner (monohull) non-stop from Martha's Vineyard to the Chesapeake Bay, 3.5 days(?), my first offshore experience. We anchored as near as possible to Jim Brown's house where we attended the wedding of Lou MacGregor and hung out for a few days; went sailing with Russell on Kauri. Over the winter of 1986/87 I was going to the mainland every two weeks with Dick Newick, video taping the construction of Ocean Surfer. We had a lot of time to talk on those ferry rides. Dick also had a shop at his house on the Vineyard where the wing mast was built and other epoxy projects took place over the next few years. http://dicknewickboats.com/oceansurfer.html During this winter, the opportunity came up for me to become a 1/3rd owner of Moxie and I jumped at the chance!! Summer of 1987 was fantastic!!! In June, four of us raced Moxie from Newport, R.I. to Bermuda, setting a _race_ record at that time of 64 hours, 49 minutes (average 10+ knots for 630+ miles, as I recall, hitting over 20 knots at times). Leaving Newport Harbor, we had 40 knots of wind on the nose, rain and ten foot seas. Ugh. Russell was in Bermuda in Kauri! Heading north to the Vineyard again from another winter in warmer places. Ocean Surfer was launched sometime that summer and I went on many of the shakedown sails, then used Moxie as a platform to video Ocean Surfer passing by. Skipper Mark Rudiger, an old friend of Russell's, showed up to train with the boat which he sailed in the singlehanded trans-Atlantic in 1988. More sails on Kauri that summer in Vineyard Sound, Wood's Hole and Buzzard's Bay. For three glorious summers, 1987..89, I sailed Moxie as much as possible (3-5 times per week) from May thru October, including delivery trips to and from Maine each season, trips to Nantucket and Newport. I continued to sail with Russell on Kauri whenever possible, in a variety of conditions, though never "offshore". In the winter of 89-90, Moxie was sold and my friend with the Catalina bought Kauri from Russell. I was originally a partner with him in Kauri but moved to California in January of 1990 before we launched the next season. I did return and sail Kauri with him, without Russell Brown on board! I lived aboard an Islander 34 (monohull) in the Berkeley Marina and frequently sailed San Francisco Bay in the fall of 1991. I spent many Saturdays working in Sausalito with Mark Ginesty (builder of Aotea and Nai'a) on the catamaran Apparition (and have sailed it alot too): http://www.apparition.com/ http://www.antrimdesign.com/aotea/index.html http://www.steamradio.com/JSYD/Images/Naia.JPG http://www.steamradio.com/JSYD/Images.html Also crewed regularly with Mike Reppy on Nai'a, usually blasting across S.F. Bay but occasionally out the Golden Gate for a little overnight up the coast at Bolinas. http://www.sfbaysss.org/transpac96/mikerepp.html In 1995, I flew to Hawaii and was one of five who delivered Double Bullet II back to L.A. in 12.5 days after the transpac. 76 feet, 15K lbs., 100' wing mast. We left the Ala Wai Yacht Harbor around 10:30am and arrived in Nawiliwili, Kauai five hours later, hitting 27 knots in the Kauai channel!! (a delivery!) Encountered 18' seas 300 miles from California, big fun. http://www.JosephOster.com/multihulls/doublebullet/ Also delivered Double Bullet II from Cabo San Lucas to Marina Del Rey. Sailed aboard 63' catamaran Profligate from San Francisco to Puerto Vallarta http://www.JosephOster.com/haha98/photos.html Oh, and about five years crewing on various race boats in San Francisco Bay, mono and multi (a wild F-25c!). So what? I'm going to dinner. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: [MHml] ultralight proas From: Joseph Oster <oster_at_wingo.com> Date: Tue, 05 Jun 2001 10:58:19 -0700 To: multihulls_at_steamradio.com Dave Culp wrote: > > > > 40' multihull for $5000 in materials and a couple hundred hours > > labor, weighing 1200 lbs, wet, and "able" to sleep 4 at sea Joseph Oster wrote: > > > > Also, let's not forget another key criteria I mentioned which minimizes > > the effect of shiftable ballast and super light (flimsy) construction > > methods: Assume we are talking about cruising proas large enough that > > crew weight is approximately 20% or less of total displacement, as with > > any typical mono or multihull longer than thirty feet or so. That means > > a boat around 3,000 lbs. or more, without crew. BINGO!! I believe this is the blind spot that has confused this discussion for so long. A single 240 lb. person would be 20% of Harry's claimed weight, two such people would be 40%! That ratio is light years away from the 50' Moxie, for example, at 10,500 lbs. where five such people would be only 10% of her displacement, or the 76' Double Bullet II at 15,000 lbs. where 1000 lbs. of crew is less than 7% of her displacement. This is a different world from ultralight proas or beach cats where moving people around makes a huge difference. I think the point is very clear in this photo of Harry's predecessor, U: http://www.schachtdesign.com/proafile/artwork/gallery/U.jpg As to the issue of 1200 lb. boats (40 feet long!?) safely crossing oceans, I doubt it. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Booms / Wishbones From: Joseph Oster <oster_at_wingo.com> Date: Wed, 18 Jul 2001 22:37:31 -0700 To: multihulls_at_steamradio.com Tom Speer wrote: > > > > What I have in mind is a rotating mast plus a wishbone Me too! Have you seen this? http://www.pacificproa.com/rig.html Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: [MHml] Re: definition of a double ended boat? From: Joseph Oster <oster_at_wingo.com> Date: Sun, 29 Jul 2001 08:43:46 -0700 To: multihulls_at_steamradio.com nudd wrote: > > > > Any double ended boat? > > I thought proas were the only double ended boats. > > Are you saying that there are boats, mono's cats or tri's that can sail in each > > direction. > > What's the definition of a double ended boat? "Canoe stern" is another term used in monohulls; bow is always bow. http://user.online.be/~cd00902/404_verkleind_2.jpg http://www.selfsteer.com/monitor/pgs12-13/Saga40.jpg http://www.laissez-faire.com/pcraft/canoe.html Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] Tennant's Wild Thing: picklefork tri From: Joseph Oster <oster_at_wingo.com> Date: Mon, 13 Aug 2001 08:24:07 -0700 To: multihulls_at_steamradio.com "David N. O'Steen" wrote: > > > > Reminds me of the 3-point Unlimited "picklefork" hydroplanes that used to > > come to Seattle each summer for a week of practice and racing on Lake > > Washington. <snip> > > But I digress. Great multihull imagery though!! Sounds like lots of fun; thanks. :) By the way, that offset hull feature and enhanced "diagonal footprint" is similar to what you find in the Pacific proa hull configuration with small "log" to weather. Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.PacificProa.com
Subject: Re: [MHml] Re: Waterskiing From: Joseph Oster <oster_at_wingo.com> Date: Wed, 24 Oct 2001 10:07:53 -0700 To: multihulls_at_steamradio.com Gary Pearce wrote: > > > > No doubt we will now get the exhaustive list of skiing photos from the web :-) Here is one of 36' proa JZERRO pulling a kid on skis: http://www.pacificproa.com/brown/waterski-s.jpg from: http://www.pacificproa.com/brown/jzerrophotos.html Mark Denovich wrote: > > > > My Prindle 19 comes up to speed more than fast enough to pull a skiier. Excuse me?!!? Can you really pull a skier behind a Prindle 19? Joseph -- http://www.shutterfly.com work: (650) xyz-1234 cell: (650) xyz-1234 http://www.JosephOster.com
Subject: Re: [MHml] ISO GPS and speed made good From: Joseph Oster <oster_at_wingo.com> Date: Sun, 23 Dec 2001 12:31:21 -0800 To: multihulls_at_steamradio.com Bill Gibbs wrote: > > > > I have several different Garmin models and all have a VMG display. I recall that some hand held models a couple years ago did not have this feature (VMG to a way point) and I found that to be a major pain, nearly useless for sailing, IMHO. > > Our B&G system has a more useful VMG capability. It calcs VMG upwind & > > downwind, not to a mark. Very cool, all right. I suppose that could be approximated on any unit by plotting a temporary waypoint "infinitely" distant in the direction of the true wind? You've made a good point about VMG dropping to zero as you approach a layline; however, when pointing directly at the mark or even deciding on the best tack with a current running, I've always considered VMG-to-the-mark to be one of the most useful tools available. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] speed predictions From: Joseph Oster <oster_at_wingo.com> Date: Sun, 13 Jan 2002 09:23:41 -0800 To: multihulls_at_steamradio.com Woods Designs wrote: > > > > 2) When I was a design student I was able to use the big college test tank > > for some research into catamaran resistance. I found the drag from wave > > interactions between the hulls to be very high, up to 20% extra drag > > compared to hulls at infinite spacing. Fascinating! 20% is a big number in this game; would you care to speculate on this phenomenon with regard to a Pacific proa configuration? Assume a Russ Brown configuration with 75% displacement (at rest) on the main (leeward) hull and 25% on the ama which is approx. 55% (half) as long as the main hull. No wish to start any silly debates, just sincerely curious. regards, Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] proas and brass monkeys From: Joseph Oster <oster_at_wingo.com> Date: Mon, 14 Jan 2002 07:40:51 -0800 To: multihulls_at_steamradio.com Woods Designs wrote: > > > > With a proa you work hard all the time. I asked about "drag from wave interactions between the hulls", not your assessment of proas in general... thanks anyway (for nothing). Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] rude people (was "speed predictions") From: Joseph Oster <oster_at_wingo.com> Date: Mon, 14 Jan 2002 10:33:48 -0800 To: multihulls_at_steamradio.com Tony Hammer called for my head... My question to Mr. Wood was in the context of the original thread topic ("speed predictions") and specifically interested in studies he had done on "drag from wave interactions between the hulls". I thought my question was specific and reasonable and stated I had "No wish to start any silly debates". So was disappointed when: a) the thread topic was changed to "proas and brass monkeys" (hah, hah) b) my question about wave drag with unequal hulls was totally ignored and c) though "nearly 25 years" since he has sailed a proa, the majority of his reply was totally negative about them! Apparently rudeness, like beauty, is in the eye of the beholder. Joseph Oster well known proa advocate -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] proas and brass monkeys From: Joseph Oster <oster_at_wingo.com> Date: Tue, 15 Jan 2002 09:38:22 -0800 To: multihulls_at_steamradio.com Rob Denney wrote: > > > > Joe said that he doesn't want to get into an argument about proas and > > their abilities. Fair enough. I, on the other hand, love to! I find nothing to argue about at all in your fine discussion of proa sailing! Very well said (this time), Rob. ;-) Cheers, Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] High prismatics From: Joseph Oster <oster_at_wingo.com> Date: Tue, 15 Jan 2002 10:32:03 -0800 To: multihulls_at_steamradio.com Richard C Shipes wrote: > > > > Am I led to believe that high prismatic hulls tend to track or go in strait > > lines, whereas a low prismatic hull is less directionally stable. > > Is this correct? You asked this question of Rob, not me, but... I would say that keel rocker and hull shape may be better indicators than prismatic alone. Example: http://www.pacificproa.com/prismatic1.gif This hull would turn more easily if the bows weren't "dragging" below the waterline. But also remember that it's the leeward hull of a beach proa which, when loaded up with two crew flying the weather hull, will be submerged "a bit more" anyway. The sides of this hull are flat panels, the bottom a "surface of revolution"; the entire hull shape is determined by the curve from midsection to bow, as seen from above. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] High prismatics From: Joseph Oster <oster_at_wingo.com> Date: Tue, 15 Jan 2002 11:05:22 -0800 To: multihulls_at_steamradio.com Joseph Oster wrote: > > > > I would say that keel rocker and hull shape may be better indicators than > > prismatic alone. Example: http://www.pacificproa.com/prismatic1.gif P.S. The very high prismatic coefficients desired in double ended proa hulls are not necessarily what you want when broad, beamy transoms are carrying your load... such as common in catamarans. Provided the keel rocker is adequate to let a boat "spin", a daggerboard and non-ventalating rudder (or pair of them) will give good directional stability to any hull, regardless of prismatic. While the generality you mentioned is often true when applied to multihulls ("high prismatic hulls tend to track or go in strait lines"), the fact is that barges have VERY high prismatics while many classic, graceful yachts have prismatics in the .30s and .40s. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] High prismatics From: Joseph Oster <oster_at_wingo.com> Date: Tue, 15 Jan 2002 19:05:11 -0800 To: multihulls_at_steamradio.com Tom Speer wrote: > > > > When looked at this way, a high prismatic boat is more of a "straight line" > > boat - it not only has fuller ends, but a slimmer middle. Right. I think of high Cp as getting more quickly to its maximum cross section and then sustaining that for a longer time with respect to the passing water... Leaving the beam, draft and length the same while allowing displacement to go up with Cp looks something like this: http://www.pacificproa.com/prismatic/ Going from Cp=.62 to Cp=.70 gains 61 lbs. displacement (12.5%) in this case. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] Lifes too short, ()but this is long) From: Joseph Oster <oster_at_wingo.com> Date: Thu, 17 Jan 2002 10:43:18 -0800 To: multihulls_at_steamradio.com "Capt. Len" wrote: > > > > a person that thinks only one type or design or idea is correct is a fool > > if he derides others that have other opinions that don't agree with his own. Makes sense to me Capt. Len! My "thanks anyway" remark to Mr. Woods was rather gracious, in my opinion, considering his negative remarks about proas. I didn't attack or deride anybody. > > Roy Mills wrote: > > > > hope to see some form of apology offered by you to the sailing fraternity > > in general. Oh please Roy! This is exactly in the same vein as Hammer demanding that I be thrown off this list. "hope to see some form of apology" is semi-nice talk for judging another person and demanding compliance to your standards. Wouldn't work in person, doesn't work here either. Get off it everybody. Go outside. Breathe some fresh air! This is stale. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] proas and brass monkeys From: Joseph Oster <oster_at_wingo.com> Date: Thu, 17 Jan 2002 16:40:45 -0800 To: multihulls_at_steamradio.com Dave Culp wrote: > > > > Calling Harry a "harry proa" isn't arrogant, it's simply erroneous. Arghhh!!! > > (FWIW, Norwood calls the design a Pacific proa, too) ACKKK!!! Dave, please, NO! Not again... Use Harry or WTW ("weight to weather") or Norwood but please do not (again!?) create confusion between this configuration and that of the traditional, WTL ("weight to leeward") Pacific proa. This attention to terminology is not about which is better (another argument), but simply that they are not the same in very fundamental ways. Since we've been all over this territory in great detail so many times before, what is your purpose now in muddying the water again? Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] greatest asset From: Joseph Oster <oster_at_wingo.com> Date: Sun, 20 Jan 2002 16:11:44 -0800 To: multihulls_at_steamradio.com David Slater wrote: > > > > To have a designer of Mister Woods ability resign from list because some > > people cannot see the advantages of real designers giving us access to > > their more technical expertise, well that's a disgrace. I don't think that's accurate... Professionals here are appreciated by all, no one argues that. In this case, I asked Mr. Woods' for his "more technical expertise" about wave interaction between hulls and didn't get it. I chose not to respond to his negative remarks about proas and thought that was the end of it (as it should have been). The rest of this hoo-hah is a creation of those who profess to be polite and teach us about proper respect (or else!) and instead create a climate of acrimony. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] Average "cruising" speeds revisited From: Joseph Oster <oster_at_wingo.com> Date: Thu, 14 Feb 2002 09:09:07 -0800 To: multihulls_at_steamradio.com Gary Pearce wrote: > > > > This months yachting World has the ARC results. <snip> > > Here is how the multihulls did: > > > > 1 Sir Henri Outremer 45 13:03:40:19 <snip> > > The fastest overall passages were: > > > > 10 Spirit of Diana Farr 65 11:23:41:43 > > 3 Lady in Red Swan 68 11:23:54:02 So... A Swan 68 monohull beat the fastest multihull by 24 hours? And was only beaten by a Farr 65? Yeah, real world results are fascinating, indeed... Joseph http://www.pacificproa.com/animate.html -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] ARC Survey Results From: Joseph Oster <oster_at_wingo.com> Date: Thu, 21 Feb 2002 11:02:03 -0800 To: multihulls_at_steamradio.com CC: Bill Edinger <Bill_at_spectrawatermakers.com> Gary Pearce wrote: > > > > After the ARC each year there is a survey of equipment used. > > > > Brief results at: http://www.yachting-world.com/ > > > > Poor old Spectra watermakers seem to have been badly let down by their > > dealers ..... again OLD RESULTS!!! That survey was done in 2000! Rather misleading at this point. I forwarded your note to Bill Edinger at Spectra and he replied: "This is from last year and is old news! You really bummed me out until we realized that this was from 2000. We took a big hit on this and have been very proactive since. I went to Las Palmas for the start of the ARC and inspected as many installations as possible." -- end quote -- Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] Transatlantic race records From: Joseph Oster <oster_at_wingo.com> Date: Mon, 25 Mar 2002 22:05:49 -0800 To: multihulls_at_steamradio.com Ed Nygard wrote: > > > > Anyone know which proa? Would that be "Funambule" (Guy Delage)? According to this page: http://www.multiplast-yachts.com/eng/design/cvollier.htm Was that proa "the first multiull" ever built by Multiplast?!? 1980... I recently created a page on this subject of West --> East Trans-Atlantic: http://www.JosephOster.com/sailing/westeast_transat.html Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] Diagonal Stability From: Joseph Oster <oster_at_wingo.com> Date: Mon, 03 Jun 2002 16:56:23 -0700 To: multihulls_at_steamradio.com Tom Speer wrote: > > > > For me, a plot of the virtual c.g. > > (http://www.tspeer.com/temp/hullbalance.gif) is a good way to bring together > > the applied loads from the sail, the righting moments from buoyancy, and the > > boat's planform. <snip> > > Do any of the designers out there look at diagonal stability this way? As we discovered off list, Jim Antrim has been using a similar diagram in lectures about what he calls the "multihull footprint"... I heard it twice, ten years ago, and understood it at the time but can't explain it now or even know if it's the same thing as what you explained in detail here: http://www.steamradio.com/pipermail/multihulls/2002-April/009171.html Since no one else replied to your note, would you care to try again explaining that diagram? I believe I understand the red lines; the black lines are a mystery, especially their connection in scale to the red lines? I don't have a copy of Larsson & Eliasson's "Principles of Yacht Design"... Thanks and regards, Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] righting moment (was Safety regs) From: Joseph Oster <oster_at_wingo.com> Date: Tue, 04 Jun 2002 08:43:54 -0700 To: multihulls_at_steamradio.com Rob Denney wrote: > > > > Any idea where Jzerro is at the moment? No. I don't even know if Russell returned to Oz this year as planned. > > ... Jzerro is the modern pacific proa which proves the type are capable of > > long distance offshore passages. It has sailed from Seattle to Brisbane (AUS) > > via LA, Tahiti and Noumea. They skipped L.A. on that trip, sailed straight from Half Moon Bay (25 miles south of San Francisco, where I live) to the Marquesas, non-stop. "a 20-day passage averaging 150 miles a day", though at times, "Even under much reduced sail, we average 180 to 200 miles a day". > > looking at the rm numbers, it also proves > > that there is more to sailing offshore than high rm. You bet! ;-) JZERRO weighs approximately three times(?) as much as Harrigami, yet has little more than half the righting moment. Very interesting indeed. I just re-read Steve Callahan's excellent Cruising World article and found this passage, commenting on this issue (p. 42): "Push the boat to reduce drag, raising the ama but not letting it come completely free of the sea. I'm surprised by JZERRO's stability. Even close reaching in 20 knots of wind, she doesn't want to fly her hull [ama] except as it leaps off wave tops. When the ama begs to fly too often, we pinch up, spill wind, reduce sail, or throw some weight into the ama. We can pump 500 pounds of water ballast into the ama if needed, but it never is. Instead, we add an anchor or extra water jug to its lockers. More often we remove weight. An overballasted ama rides heavily and, after leaping off a crest, slams back into the waves, racking and shaking the whole boat." Joseph -- http://www.PacificProa.com
Subject: Re: [MHml] Pilothouses From: Joseph Oster <oster_at_wingo.com> Date: Fri, 07 Jun 2002 07:56:05 -0700 To: multihulls_at_steamradio.com Paul and Barbara Nudd wrote: > > > > From my experience on catamarans (and I really have no experience on > > anything else) I want to spend my time as far back as possible. > > Even going as far forward as the mast can be enough to set me off > > (seasick). My experience on the 76' catamaran Double Bullet was that both ends of the boat could pitch up and down, given the right conditions. The base of the mast near the center of the boat was the most stable position of all, being near the axis of rotation. It was also the driving position (completely unprotected!): http://www.JosephOster.com/multihulls/doublebullet/db-4-l.jpg A proa, of course, also has a center cockpit at the base of its mast which is quite convenient for sail handling, reefing, etc., and has a comfortable motion. I am a fan of interior steering myself, having shivered through some long night watches in the rain and cold. Even when it's dry, alertness and endurance are enhanced by comfort and warmth. By the way, I have a bunch of nice photos I took sailing with Bill Anderson on FEET, which has a walk through dodger and forward cockpit at its mast base: http://www.latitude38.com/LectronicLat/2001/Oct2001/Oct16/Oct16.html#anchor25895733 Unfortunately, I need to buy a new computer before I can get the digitized photos off the CDROM and post them to a web page. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] Pilothouses From: Joseph Oster <oster_at_wingo.com> Date: Sat, 08 Jun 2002 08:18:55 -0700 To: multihulls_at_steamradio.com Paul and Barbara Nudd wrote: > > > > Upwind, downwind, reaching, even at anchor, the axis of rotation appears > > to be about 2' forward of the transoms. > > Don't know if this is a function of length, weight distribution, hull > > shape/buoyancy distribution? Most likely due to a full, "flat" planing underbody shape aft which efficiently carries lots of weight and reduces pitching. Double Bullet II has extremely skinny hulls with transoms that are almost as fine as her bows so in that respect she behaves more like a double ended proa. http://www.JosephOster.com/multihulls/doublebullet/db-2-l.jpg I remember leaning against the aft crossbeam at one point and realizing that the G-forces there were lifting us off our feet and it would be much safer and more comfortable forward. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234
Subject: Re: [MHml] RE: COB/Pitch (was Pilothouses) From: Joseph Oster <oster_at_wingo.com> Date: Sun, 09 Jun 2002 09:24:26 -0700 To: multihulls_at_steamradio.com Mike Nicholson wrote: > > > > If you look at the multihulls side-on, there is quite a variation in how > > the rocker is distributed longitudinally. As a generalistation (always > > dangerous!), later model, light, fast boats seem to have the maximum rocker > > well aft, where the load carriers seem to have the maximum fairly central. Would be nice to see some examples? My guess is that the effect on pitching, hobby-horse motion has more to do with the breadth of the transom rather than depth or location of maximum rocker. A wide transom, even if it's very shallow, will reduce pitching moment because of its high lbs./inch immersion rate. Extreme example of this would be a typical powerboat hull/rocker shape where maximum rocker depth is well forward and the hull is wide and shallow aft: http://www.kaufmandesign.com/thomaspoint30.ex2.lg.jpg In a multihull, maximum rocker depth is usually a function of waterline beam, cross sectional area and prismatic coefficient. The goal of reducing wetted surface area leads to the semi-circular cross section (or something close to it, even hard chine) with a beam:depth ratio of 2:1. I don't see the connection between rocker depth and COB location. A proa hull, of course, always has its maximum rocker and COB in the center of the boat (being identical at both ends) but I can imagine catamaran hulls shaped more like power boat hulls. Referring to Tom Speer's diagonal stability diagram, remember that COB (the red lines) must move forward and outboard of the virtual center of gravity (the black lines) caused by pressure in the sails to keep the boat upright: http://www.tspeer.com/temp/hullbalance.gif So how does one explain the pitch axis of rotation on Paul Nudd's cat "appears to be about 2' forward of the transoms" when its COB (and c.g.) must clearly be far forward of that? Again, I believe it's because the wide shallow transom shape inhibits immersion of the stern. Perhaps, in some sense, the axis of rotation is actually further forward but bouncing up and down at half the speed of the bows due to the stability of the wide transom? Visualization: Hold a pen using both hands; grab one end with your right hand and don't let it move up and down; grab the middle of the pen with your left hand and move it up and down... The pen/boat is rotating around its center of gravity (axis in your left hand) and also rotating around an axis in your right hand (transom) which is hardly moving at all. Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] RE: COB/Pitch (was Pilothouses) From: Joseph Oster <oster_at_wingo.com> Date: Tue, 11 Jun 2002 09:59:46 -0700 To: multihulls_at_steamradio.com Paul Nudd wrote: > > > > I am not saying the boat won't move in this way. I am saying the pen > > cannot move in this way - by definition. > > I don't have any trouble visualising the movement except when I use > > Joseph's self contradictory pen analogy. This is a point of view problem... To you, the pen appears to rotate only around the axis in your right hand that isn't moving up and down (the transom). If you are sitting at the pen's center of gravity (the middle of the pen in your left hand), the horizon appears to rotate exactly the same number of degrees as it does when sitting at the transom (or bow, for that matter). The only difference is that you are also going up and down to a greater or lesser degree, depending on how far you are from the axis that isn't moving (in this case at the transom). The pen analogy is useful, in my opinion, because any object floating in free space will first start to rotate around its c.g. in response to any force applied that isn't in a direct line through its c.g. Steerable engines on the space shuttle, for example, are crucial for keeping it moving in a straight line instead of tumbling out of control. On a boat, gravity, buoyancy and the shape of the waterplane area (along with other factors) quickly contribute to the overall motion and response to lifting the bow, causing the pitch axis of rotation to locate itself wherever equilibrium dictates, even moving fore and aft as the boat pitches, depending on hull shape. > > Anyway it doesn't matter what axis the boat is or is not rotating > > around... Don't you agree that it would be nice to predict in advance where this stable point, the pitch axis of rotation, will be located on any given design? As a start, I would consider the location of c.g. relative to the shape of the waterplane area (which may change as a function of pitch). On a proa where a wide transom isn't an option, the best defense against excessive pitching is a long waterline and high prismatic coefficient. Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] Leeboards From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Jun 2002 08:56:49 -0700 To: multihulls_at_steamradio.com Roy Mills wrote: > > > > Also as the windward hull lifts... <snip> to > > the point that Tom has been considering in his lateral footprints, the > > complete lack of any board in the water at all might cause the whole boat > > to skid out sideways, thus bringing the windward hull back down again, This is exactly what happens on Russell Brown's proas when the ama flys "too high" and the daggerboard clears the water; a noticeable shift to leeward, which is favorable in these circumstances, giving the helmsman an extra margin in which to take corrective action. Joseph -- http://www.JosephOster.com
Subject: Re: [MHml] Re: Diagonal stability. From: Joseph Oster <oster_at_wingo.com> Date: Mon, 17 Jun 2002 21:08:05 -0700 To: multihulls_at_steamradio.com Steven Tripp wrote: > > > > I take it that from experience they had learned that these "wings" would > > hold the bows up enough to prevent flooding. Sounds like the anti-dive planes used on Dick Newick's proa CHEERS (1968): http://dicknewickboats.com/cheers/cheers_mrb.jpg http://membres.lycos.fr/ugmarie/zacheers/cheersjpg/rougevinbaville/cheersparrougevinbaville0005.html Joseph -- http://www.JosephOster.com
Subject: Re: [MHml] Re: Multihulls From: Joseph Oster <oster_at_wingo.com> Date: Mon, 24 Jun 2002 16:46:12 -0700 To: multihulls_at_steamradio.com Ted Warren wrote: > > > > Walter Greene is one of the most accomplished multihull yachtsman that we > > have, having many offshore miles, trophies and awards, an honorary lifetime > > member of NEMA, and a nice guy. Agreed! > > but still there it is, an expert and capsize. Same goes for Jim Antrim and Aotea: http://www.antrimdesign.com/pitchpole.html Of the two VERY OLD issues you mentioned, going to windward is a non-issue as far as I'm concerned. Problem has been well understood and solved for decades. Solution is a deep daggerboard foil instead of "mini-keels". And low windage hulls help too, of course, as John Shuttleworth and Tom Speer have mentioned. As to capsize, stability "footprints", etc., the only innovative and really different approach I've seen yet is the Russell Brown style Pacific proa. It has an excellent "footprint" for resisting pitchpole and the leeward pod to give the helmsman a second chance when knocked over sideways. Of course, even less than other performance oriented multihulls, proas aren't for everyone (yet). The fact is that no multihull is self righting in the same sense as a ballasted monohull. Once flipped by wind or wave, they'll generally remain that way (Great American being the only exception I know of where it was flipped upright again by wave action in horrible conditions off Cape Horn. Welcome to the list, Georgs Kolesnikovs! Care to tell us more about that incident?). Other than the good advice to "know your boat and pay attention", the greatest hope, I would think, is a "smart boat" that takes better care of itself using sensors and a computer, warning the skipper about impending doom and as a last resort, sacrificing the mast to prevent overturning. Gotta have some major fail safes on that plan though! Would be terrible to drop the mast by accident!! Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] List Etiquette From: Joseph Oster <oster_at_wingo.com> Date: Tue, 09 Jul 2002 18:49:16 -0700 To: multihulls_at_steamradio.com Peter Warde wrote: > > > > I will post a summary for those who are interested in a day or so when all > > the numbers are in. It is also considered common courtesy to not reveal publicly the content of emails received off list. Doing so is rightfully considered a violation of privacy. So your suggestion that "answers are sent to the person who placed the original post who then posts a summary of the responses" is NOT a reasonable expectation, in my opinion. This list is notorious for disregarding "netiquette", especially when it comes to trimming the full text of the previous post when replying (a personal pet peeve of mine). However, another violation in this vein is excessive size of the "signature" and I'm afraid you are guilty of this yourself. Your extremely verbose address information and the paragraph about "This communication is confidential..." attached to your email takes more bandwidth than many a brief reply and is inappropriate for regular contributions to the list. Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] performance From: Joseph Oster <oster_at_wingo.com> Date: Tue, 16 Jul 2002 10:24:05 -0700 To: multihulls_at_steamradio.com Bill Gibbs wrote: > > > > The basic premise of PHRF handicaps is that only the handicap value > > represents boat performance. Right! Here is the BAMA rating list, ranked from slowest to fastest: http://www.JosephOster.com/bama/2001/ratings.html Note that the F27 is another twenty seconds faster per mile (even more for the square top main) than the F24 and both boats are substantially shorter than the Gemini. Ratings may differ depending on the fleet and local conditions, though relative boat performance potential remains similar. Here is the ratings page for the Florida Offshore Multihull Association: http://foma.sailnet.com/foma_ratings_0401.html And the Northwest Multihull Association: http://www.nwmultihull.org/racing/racingratings.htm Jean Daugherty wrote: > > > > I'm referring to the Chesapeake Bay... Read light air, thin water... I'd be interested to see the PHRF ratings for these boats in Chesapeake Bay, to see if/how they differ from windy San Francisco Bay? > > The discussion is not (repeat NOT) about racing. Its about value. Granted. I met a couple in 1998 who had a grand adventure sailing their Gemini from S.F. Bay through Mexico, the Panama Canal and the Caribbean. However, for those of us who've had the pleasure of routinely sailing at speeds twice as fast as those you mentioned for the Gemini, the criteria for value may be different. To me, a fast monohull is a better value than a slow multihull. Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] Tilting rig From: Joseph Oster <oster_at_wingo.com> Date: Mon, 22 Jul 2002 13:32:36 -0700 To: multihulls_at_steamradio.com Tony Hammer wrote: > > > > Does anyone know what the advantages if tilting the rig to windward > > quantitatively are? Mark Rudiger said he only tried it once when singlehanding Dick Newick's Ocean Surfer in the 1988 C-STAR (trans-Atlantic race). He _DID_ observe an increase in performance as it allowed him to catch up and pass another boat he had been following behind for some time. http://dicknewickboats.com/oceansurfer.html Also see Chris White's work on this subject using a beach cat: http://www.JosephOster.com/chriswhite/tiltrig.html Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] Re: unstayed rigs (long) From: Joseph Oster <oster_at_wingo.com> Date: Sat, 27 Jul 2002 11:14:45 -0700 To: multihulls_at_steamradio.com Tom Speer wrote: > > > > I think a good candidate for a free-standing mast would be an egg-shaped cross > > section, with the narrow end forward. The mast would be rotated inside the > > luff sleeve just like conventional wingmasts. The rounded backside of the > > mast would allow for a smooth transition between the mast and sail at a > > variety of mast angles. Sounds very good Tom, an excellent shape for a tapered carbon tube! Can we order them as a kit with bearings in sizes up to 60 feet or so? ;-) Handling a sleeved luff sail is old stuff, and is far easier on an unstayed mast, as the whole spar can be used. It will always help to unload the wind pressure, if possible, before moving the sail up or down. What about battens? And big headboards on high roach, "square top" mainsails? Joseph -- http://www.pacificproa.com/
Subject: Re: site customs, was Re: [MHml] New Swedish trimaran From: Joseph Oster <oster_at_wingo.com> Date: Tue, 06 Aug 2002 10:39:52 -0700 To: multihulls_at_steamradio.com Tom Schoettle wrote: > > > > and here is the rest for all those getting only the first page and nothing more: But those HTML pages don't work either using Netscape 4.79, for the same reason, Error 404 (file not found) for http://www.seaon.com/NewFiles/main.css MSIE doesn't object to the missing file, Netscape does. Problem would go away if a) NewFiles/main.css file were placed on the server or b) reference to same was removed from all HTML source code. Links directly to images and the PDF format brochure are browser independent though: http://www.seaon.com/broschyr.pdf > > http://www.seaon.com/images/general.jpg > > http://www.seaon.com/images/folding.jpg > > http://www.seaon.com/images/comfort.jpg > > http://www.seaon.com/images/CNV00006.jpg The source indicates "Adobe GoLive 6" was used to create the web site... Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] Maiden II Clarification Needed From: Joseph Oster <oster_at_wingo.com> Date: Wed, 07 Aug 2002 10:13:35 -0700 To: multihulls_at_steamradio.com GABarker_at_aol.com wrote: > > > > What specifically was Maiden II's recent accomplishment again? 24 Hour Record of 697 miles on June 13th, 2002. "speeds clocked at 44 knots and an unofficial average speed of 29 knots" With some help from the Gulf Stream: http://www.JosephOster.com/sailing/maiden2.html Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] A new Cuising Cat From: Joseph Oster <oster_at_wingo.com> Date: Sat, 10 Aug 2002 07:40:19 -0700 To: multihulls_at_steamradio.com Dan White wrote: > > > > "The new Maine Cat 38 was delivered to her home in Marblehead Harbor... Specs and photos of building the Maine Cat 38 here: http://www.mecat.com/MC38photoalbum.htm And photos of Ian Farrier's cool New F-41 (and F-44) here: http://www.f-boat.com/pages/catamarans/ http://www.f-boat.com/pages/catamarans/launching.html http://www.f-boat.com/pages/catamarans/interior.html http://www.f-boat.com/pages/catamarans/Sailing.html Boats of this size and capacity are very interesting to me, being about the minimum space I would consider comfortable for full time live aboard cruising, especially with company. My preference is to re-arrange it as a much longer proa, keeping the weight, rig and interior space roughly the same, but that's just vapor, these boats are real. Off to join Bill Anderson today on "FEET" for a sail around S.F. Bay! http://www.latitude38.com/LectronicLat/2001/Oct2001/Oct16/Oct16.html#anchor25895733 http://hometown.aol.com/wla39/ Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] Carbon tube From: Joseph Oster <oster_at_wingo.com> Date: Tue, 13 Aug 2002 16:54:35 -0700 To: multihulls_at_steamradio.com Roy Mills wrote: > > > > About a year ago someone on this list gave us a url for a company > > in the US which manufactured a very comprehensive array of glass and carbon > > rods, tubes etc. I regret to say I deleted it just 3 weeks ago... I keep all my archives and they are searchable! http://www.cstsales.com/carbon-tubes.htm (from 10 Jan 2002, Marcus Tomblin) And: http://www.exelindustry.net/tubesandprofiles/index.php (from 11 Jan 2002, Sture Erickson and 13 Oct 2001, Gary Pearce) Then there's the FIBERSPAR dealer network: http://showvantage.com/fiberspar/ Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] 313' australian cat From: Joseph Oster <oster_at_wingo.com> Date: Thu, 15 Aug 2002 08:59:27 -0700 To: multihulls_at_steamradio.com Robert_at_Sail4Life.net wrote: > > > > http://www.tribnet.com/news/local/story/1593812p-1711139c.html Pictures here: http://198.65.138.161/military/systems/ship/hsv-gallery.htm http://www.dtic.mil/armylink/news/Oct2001/a20011022hsv-1test.html http://www.news.navy.mil/search/display.asp?story_id=3070 Joseph -- http://www.PacificProa.com
Subject: Re: [MHml] Re: A New Cruising Cat From: Joseph Oster <oster_at_wingo.com> Date: Thu, 15 Aug 2002 10:32:07 -0700 To: multihulls_at_steamradio.com TLam45387_at_aol.com wrote: > > > > The emphasis on no, or minimal, deck houses is > > also a part of the idea. I noted in the pics. that Anderson's hard dodger > > became narrower at some point after launching. Sort of as in the F41's but > > lower to the deck. Was waiting for Bill Anderson to comment on this himself but I don't believe any modifications were made to the dodger after launching. The dodger and cockpit area are intended to protect a small crowd of charter guests so it's fairly wide, also protecting the helmsman who stands against the aft crossbeam and grabs the long, sliding horizontal tube that is the tiller. http://www.latitude38.com/LectronicLat/2001/Oct2001/Oct16/Oct16.html#anchor25895733 http://hometown.aol.com/wla39/ I noticed that my friends at Adventure Cat have posted photos of their new 65' catamaran, built in Gray's Harbor, Washington state, soon to be on S.F. Bay. Note the lifelines! http://www.adventurecat.com/boat-photos.html Joseph -- http://www.pacificproa.com/
Subject: Re: [MHml] 313' australian cat From: Joseph Oster <oster_at_wingo.com> Date: Sat, 24 Aug 2002 07:57:41 -0700 To: multihulls_at_steamradio.com Sighted at the Golden Gate doing "30 knots or more"! http://www.latitude38.com/LectronicLat/2002/Aug2002/Aug21/Aug21.html#anchor739491 Robert_at_Sail4Life.net wrote: > > > > http://www.tribnet.com/news/local/story/1593812p-1711139c.html Joseph Oster wrote: > > > > Pictures here: > > http://198.65.138.161/military/systems/ship/hsv-gallery.htm > > http://www.dtic.mil/armylink/news/Oct2001/a20011022hsv-1test.html > > http://www.news.navy.mil/search/display.asp?story_id=3070 Joseph -- http://www.PacificProa.com
Subject: [MHml] JZERRO sailing exploits From: Joseph Oster <oster_at_wingo.com> Date: Fri, 18 Oct 2002 08:26:45 -0700 To: MhMl <multihulls_at_steamradio.com> Aloha, FYI, I just got email from Russell Brown who is sailing his proa JZERRO in Australia and planning to cross over to New Zealand in December. Among other things, he mentioned the following: 1) "I did get to take David Lewis sailing - a really good sail and hove to offshore to go below and drink tea and rum and eat cookies." NOTE: David Lewis wrote "We, the Navigators" (The Ancient Art of Landfinding in the Pacific). 2) He did a race in Airlie beach and referenced a story about it on the emultihulls.com web site under "Whitsunday Multihull Rendezvous": http://www.emultihulls.com/Pages/multi_rendezvous/multi_rendezvous.htm From that page: [--quote--] Another welcomed International guest amongst the 'troops' was the affable Russell Brown on his beautiful proa, JZERRO. Any doubts on proa performance were obliterated throughout the Regatta as the liveaboard cruiser stormed start and finish lines to take All Out Line Honours in the Cruising Division. The 37 footer of Russells' own design provided the fleet with some amazing spectacles as it continually powered off into the distance, leaving a slightly unusual wake in its' track! Russell and crew member, Mark Lamb worked extremely well together to pull maximum speed at every opportunity. Within the first hour of Race One it became obvious JZERRO was in the wrong Division... Racing definitely more their league but... shoulda, coulda, woulda... there's always next year Russell! Needless to say, their handicap on the morning of Race Two bore very little resemblance to the original and popped them out of the placing picture. Their elapsed times continued to impress, however, and they would have been chasing the 'Big Boys' for sure (EMULTIHULLS.COM and ROOM) had they been running the Racing Division. Even David Mitchell on the speedy Crowther 36' tri, SPIRIT, was astonished when JZERRO sliced past them at an awesome rate of knots. "We were registering 17 and they literally flew past us..." David said. [--end quote--] Joseph -- http://www.pacificproa.com/brown/jzerrophotos.html _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] JZERRO sailing exploits From: Joseph Oster <oster_at_wingo.com> Date: Sun, 20 Oct 2002 09:49:30 -0700 To: multihulls_at_steamradio.com Joseph Oster wrote: > emultihulls.com web site under "Whitsunday Multihull Rendezvous": > http://www.emultihulls.com/Pages/multi_rendezvous/multi_rendezvous.htm (now quoted here: http://www.pacificproa.com/brown/jzerrophotos.html) Dave Culp wrote: > > Probably says more about Russ as a designer than about proas per-se, but you just never know... ;-) A combination of factors, including his lifetime of experience... The right idea (weight to leeward!), well implemented in modern materials, a "conventional" high performance sailing rig. Having only one hull in the water has to be the fastest, eh? That's the way they sail the super cats (PlayStation, Maiden 2), when possible. I later noticed a link to photos from above page and found this one of JZERRO: http://www.pacificproa.com/brown/jzero_wsr.jpg Apparently similar speeds, though flatter conditions (and less weight?) to this one of you and I on the bench seat doing "about 20 knots" (summer, 2000): http://www.pacificproa.com/brown/jzerro_lat38.jpg What fun! Joseph -- http://www.JosephOster.com/ _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] steering on jzerro From: Joseph Oster <oster_at_wingo.com> Date: Sun, 20 Oct 2002 10:08:49 -0700 To: multihulls_at_steamradio.com s wrote: > still i'm wondering how that 'famous' russ brown did the stearing on his jzerro. First, on alternate tacks, the rudders can be raised and lowered quickly from the center cockpit using uphauls and downhauls; they are light. Here are a couple of close-up photos showing the forward rudder in the raised position: http://www.pacificproa.com/brown/surfing-l.jpg http://www.pacificproa.com/brown/kauari-helm-l.jpg The rudders are designed to collapse aft within the trunk if something is hit. Most of the space aft of the shaft is air, except for a couple of blocks of foam. A side angle photo shows that a little better: http://www.pacificproa.com/brown/kauari-portbow-l.jpg The whole linkage is above deck, simple and obvious (i.e., reliable!). Joseph -- http://www.pacificproa.com/brown/jzerrophotos.html _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] Re: JZERRO sailing exploits From: Joseph Oster <oster_at_wingo.com> Date: Sun, 20 Oct 2002 18:16:29 -0700 To: multihulls_at_steamradio.com Mark Stephens wrote: > > It will be interesting to see just how right the idea of "weight to leeward" > is when Rob Denny races his Racing Harrigami next year and one of the five > Visonarrys under construction are launched. Yeah, I've been hearing that for several years now... He'll have to safely cross a few oceans as well as be faster around the cans to prove that point. The benchmark has been firmly established by JZERRO and its predecessors. > http://www.pacificproa.com/brown/jzero_wsr.jpg shows a fellow hiking out on > the windward float. The logical evolution would be to give the poor guy some > comfortable accomodation (and weight advantage) out there, a la > www.harryproa.com. But then the ama will never fly! Virtually by definition, a Harry proa will not fly the weather hull so will always be dragging two hulls through the water, with resulting greater drag. Experience shows that keeping it "on the edge", just flying the weather hull, is the fastest condition and pretty doable, given around 25%..30% displacement to weather and a buoyant leeward pod to prevent capsize. Besides moving rail meat, water ballast is available to achieve that. Having excessive lateral stability (as in the Harry style proa) means the ama will always drag; and in the most extreme conditions, the boat will ultimately pitchpole first before it rolls over sideways. Cheers, Joseph -- http://www.JosephOster.com/ _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] Re: JZERRO sailing exploits From: Joseph Oster <oster_at_wingo.com> Date: Mon, 21 Oct 2002 10:24:01 -0700 To: multihulls_at_steamradio.com > On Sunday 20 October 2002 18:16, Joseph Oster wrote: >> Having excessive lateral stability (as in the Harry style proa) means >> the ama will always drag; and in the most extreme conditions, the boat >> will ultimately pitchpole first before it rolls over sideways. Tom Speer wrote: > I don't understand this at all. Isn't it obvious that performance oriented catamarans and trimarans, using "only" 50% displacement to weather, commonly pitchpole before rolling sideways when pushed to their stability limit? Harry style proas, when pushed to utilize all their extra righting moment, will behave the same way, only more so. The phrase "more sail carrying ability for the same length" can be misleading in this regard. There is no point in carrying so much sail that the leeward bow is routinely driven under. Joseph -- http://www.pacificproa.com/ _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] Re: JZERRO sailing exploits From: Joseph Oster <oster_at_wingo.com> Date: Mon, 21 Oct 2002 14:08:19 -0700 To: multihulls_at_steamradio.com Tom Speer wrote: > > I hadn't realized proas were more sensitive in that regard than a conventional hull. Makes sense, though. I would say that a weight to leeward ("Pacific") proa is less sensitive to burying the leeward bow than other multihull forms, precisely because it is designed to "roll over" (lift the ama) before pitch poling. That "footprint" of center of gravity vs. center of buoyancy diagram you created will support this, I believe. The sails are far more likely to knock it onto the leeward pod before a pitch pole can occur. The Harry proa style seems to me similar to an extreme trimaran, capable of flying the main hull. In that case, like Harry proas, more than 50% displacement is levered out to weather, creating tremendous lateral stability for a given length. Exciting, for sure. And more likely to trip over a stuffed bow than a weight to leeward proa operating with less sail power on a larger leeward hull. Also, as we've discussed before, angular momentum of center of gravity with respect to center of buoyancy is far greater with Harry style (weight to weather) proas and minimized with weight to leeward ("Pacific") proas because the C.G. is located further from the leeward hull in Harry, closer in "Pacific" style. In a sudden deceleration, such as stuffing the leeward bow into a wave, this extra angular momentum in Harry will contribute more stress to the crossbeams and unwanted "spin" to the whole structure. Just my opinion, Joseph -- http://www.pacificproa.com/ _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: [MHml] "Mbuli", Pacific proa plans! From: Joseph Oster <oster_at_wingo.com> Date: Sat, 02 Nov 2002 17:06:53 -0800 To: MhMl <multihulls_at_steamradio.com> FYI, since I've seen no mention of it here yet, Chesapeake Light Craft is now offering plans for "Mbuli", a 20' Pacific proa by John Harris: http://www.clcboats.com/pacificproa.php3 Nice WoodenBoat Magazine review: http://www.clcboats.com/pacificproa_wb_article.php3 Drawings: http://www.clcboats.com/images/proadraw1.jpg http://www.clcboats.com/proaparts.php3 http://www.clcboats.com/proadraw2.php3 Looks GREAT!!!!! Joseph -- http://www.JosephOster.com/ _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] a proa? From: Joseph Oster <oster_at_wingo.com> Date: Sun, 03 Nov 2002 08:03:50 -0800 To: multihulls_at_steamradio.com donald mchardy wrote: > I suppose it's a proa? > www.blue70.com/sailrocket Whatever it is, that hull shape is radical! Negative rocker!! Water shedding shape raised between two planning ends. And flying the LEEWARD hull, the way Dave Culp sails his kite boats. Very cool, Joseph -- http://www.PacificProa.net _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] Re: MOXIE!!! From: Joseph Oster <oster_at_wingo.com> Date: Thu, 14 Nov 2002 07:38:00 -0800 To: multihulls_at_steamradio.com David N. O'Steen wrote: > still looked so graceful at nearly 20 years old; 23 years old; she won the 1980 OSTAR (singlehanded trans-Atlantic), remember? > some **** had installed an inboard engine Yeah, I cried when I heard that. Not only much heavier but that aft lazaret area was perfect for an owner's cabin. Moxie has undoubtedly gained weight over the years, which certainly slows her down. Photos of me on board: (small) http://www.pacificproa.com/about/on_moxie1x284.jpg http://www.pacificproa.com/about/on_moxie2x284.jpg (and large) http://www.pacificproa.com/about/on_moxie1x1000.jpg http://www.pacificproa.com/about/on_moxie2x1000.jpg Gotta run. Cheers, Joseph -- http://www.JosephOster.com cell: (650) xyz-1234 _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls
Subject: Re: [MHml] hulls & righting moment (was What is a keel?) From: Joseph Oster <oster_at_wingo.com> Date: Fri, 22 Nov 2002 10:33:54 -0800 To: multihulls_at_steamradio.com Paul and Barbara Nudd wrote: > If we put a little float under the sliding seat on an international > canoe, to prevent capsizing if caught aback, or if we put a little float > under the ballast at the end of the lever arm/keel/whatever, for the > same purpose, what do we have then? A tacking outrigger. If it has two bows and shunts, it's a Pacific proa (main hull to leeward, ama to weather). Bill Gibbs wrote: > Unlike the several "literal" fanatics on the list, I found your Kingfisher "stretched allusions" thought provoking. Obviously a "hull" provides buoyancy. But a flying hull doesn't, at that time. It becomes a weight contributing to righting moment, exactly as a keel does, and a swinging keel even more so. I'd never thought about these parallels before. That's what happens, Bill, when you dismiss people as "literal fanatics" and stop listening to them. This analogy to a Pacific proa has been made many times before. > PS I omitted the rather lengthy thread for you, Joseph :-) That's decent of you Bill, but guess what? Calling attention to the fact that you stopped being lazy and leaving crap to clutter hundreds of hard drives is nothing to brag about. It's only the civilized, considerate, respectful thing to do. Terms like "trim nazis" are not appropriate and indicate the kind of unrepentant attitude typical of the most flagrant polluters on the planet. That you need to be reminded so frequently is your doing, not mine. Joseph -- http://www.JosephOster.com cell: (650) xyz-1234 _______________________________________________ Multihulls mailing list Multihulls_at_steamradio.com http://www.steamradio.com/mailman/listinfo/multihulls

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