: My understanding is a high aspect ratio sail is one which is tall and skinny
: rather than short and broad. The Balogh batwing sail looks like a high
: aspect sail to me so I assumed it was.

: My rig is a monohull with outriggers. All of the boats using Balogh's mast,
: sail and AKA's and AMA's assembly and other similar setups all seem to
: sail well whether the unit (sail, mast, leeboard) are positioned in the
: front, middle or rear of the monohull. So using a clone setup like them,
: it's hard to see how the sail, leeboard position could go wrong.

: My understanding is that no stretch in a sail is what we are looking for so
: it will hold its shape. So Dacron sails are better then Nylon sails
: because Dacron has less stretch.

: To build a sail similar to Balogh's batwings, you could use his sizes, which
: are on his site and then use the NACA foil shapes to get the shape and
: depth (chord) of the sail. Then white poly (don't know why this is any
: better then blue poly) could be used to make a cheap first sail. But
: better yet you could use Tyvek made by Dupont, which is a non-stretchable
: paper that is almost impossible to tear. It can be taped or sewed. You see
: this material as a wrap around new houses that are being built. Go to the
: post office and get a free large Priority Mail envelope. This is Tyvek.
: Try to tear it. Good Luck. If you should make a sail, post your results
: and pictures.
: Cheers,
: John

Yes, high aspect foils are (for sails) tall and skinny. Not necessarily what you want though, a low aspect (short and fat?) would be better, you don't exactly have a huge reserve of righting moment on a kayak even with pontoons attached. Also a kayak is a very easily driven hull, you don't really need alot of extra power.

Bill H.