Rudders that Swing up ninety degrees and still rotate 360 degrees
Rotates 360 degrees and still kicks up. Perhaps a connecting rod going up the center of the shaft, spring loaded, pulling to keep the rudder down, yet allowing it to snap up 90 degrees quickly or be set at some angle for less board area forward?
Green line is top of faired bracket which is attached to vertical rudder post and can rotate 360 degrees at all times.
High side loads and rapid rotation might be expected when the rudders is up, especially in a shunting situation where the direction is instantly reversed.
Physical mock up using a Hobie 21 rudder (36" long, 11.25" max. chord) - blue area is 8.75" high, a "bracket" attached to the rudder shaft providing a swing point for (and firm grip on!) the rudder. One has to imagine this faired like the base of a dorsal fin with a perfectly matched rudder, correct rudder shaft alignment, the right combination of art and engineering!
(*) NOTE: orignal idea used large diameter tube "rudder shafts" and a flat spot on the hull to allow extracting the rudders through the hull; if this external hinge is treated more like a conventional spade rudder that is extracted from below, then standard size rudder shafts and bearings can be used.
This illustrates two possible mechanisms that rotate 360 degrees, exiting the bottom at a flat spot (*) on the hull, acting as a sturdy base for a faired hinge that allows quick break away ("kick up") capability and perhaps partial deploy (swing back) when less forward area is needed:
- the knife design has faired "cheeks" surrounding the rudder blade, extending from the rudder shaft, holding the pivot point sufficienctly outboard - GREATEST POTENTIAL because the leading edge can be a fixed, faired shape, "always forward"
- the beer opener has a single pivot stub with "cheeks" on the rudder instead
Joseph Oster - 15 April, 2006
