Bucky Boom
Balanced Wishbone Rig for Sailing Pacific Proa

Inspired by Buckminster Fuller and designed by Jim Antrim, this lightweight rig for a 21-meter Pacific Proa rotates 180 degrees on each tack, carrying the jib around with it. A modified wishbone rig, it is composed of struts and wire stays, isolating compression and tension forces in the "boom".
The wing mast rotates independently of the boom.

Comments on Bucky Boom: by Joseph Oster, based on three days experimenting with a physical model...

Sat, 19 Jan 2002 10:34:51
What is so exciting is that it feels really solid and effective when vertical tension is applied at the aft end of the boom. All my earlier efforts had attached the "main halyard" there and I got some pretty exciting results. The problem, as I mentioned, is what happens when you release that main halyard and push down on the end of the boom? Crash!

Thu, 03 Jan 2002 12:04:23
the aft end of the boom _MUST_ be supported at all times, even when the main sail is down; stability of whole rig depends on it!

Fri, 18 Jan 2002 13:36:01
Even allowing for precise geometry, wire shrouds that don't stretch, a half dozen different rigging methods, etc., all efforts fail and the "boom" collapses when topping lift tension is relaxed.

I can't seem to make the geometry work without a loaded mainsail pulling vertically on the trailing edge of the boom. Even then, lifting any of the four "corners" of the mid-section can too easily collapse the boom.

Aside: Seems well worthwhile to totally separate mast rotation from boom rotation if possible; I'm using a rotating base below the mast which has anchor points for the boom wires. It spins with the boom (on the mast axis) and allows the mast above it to rotate independently, without tightening any boom rigging. Works really well!

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