This is something I've been hoping for some while would pop up here. I have plans for a stretched & narrowed (23'-8" x 24") version of the Shearwater Double Baidarka that Eric Schade drew for me and I intend to produce a full-blown sailing trimeran based on it. I've seen the new version of CLC's SailRig on the water (just Saturday) and, while nice and reasonably well designed, it doesn't meet my need for speed.

I'm looking to provide enough sail area to get the main (kayak) hull out of the water. To accomplish this the leeward ama must have enough volume to support the full displacement of the craft (inc. people, gear, etc...) and not imitate a submarine. While surface-piercing multihulls are all the rage these days, the conventional wisdom says the ama volume should be 200% of the working displacement of the boat.

Once you get the power required and keep the leeward ama from sounding it becomes an issue of drag and stability (as Roger said). For minimal drag most racing multihulls seem to have gone to hulls with almost circular sections amidships and fine vertical bows. Sterns seem to vary but some flattening toward a beavertail look with almost planning sections aft is common at the high-speed end of the sport. Stability becomes an issue of balance between the center of effort of the sail(s) and the center of lateral resistance and both of these can be tweaked rather easily.

John: the asymmetrical outrigger/ama has been done (evidence Hobie) but as a long-time Hobie 14 & 16 sailor I can assure you it doesn’t work very well, leeway is significant in those boats. There are even a fair number of asymmetrical proas sailing around without leeboards of any type. However, to me at least, the trade off in drag and difficulty of design is not worth it when a proper leeboard/centerboard/daggerboard is relatively easy to build, mount, and operate.

Well, thanks for letting a newby spout. Any ideas on my pet project here are more than welcome. Thanks for all the inspiration provided so far.

Porter