A sailboat sail is just a wing stood on end. A single surface, non-rigid
sail is like a hang glider. A solid two-surface sail is like a sailplane
wing - far more efficient. An ultra-light, carbon fiber, rigid sail offers
a potentially huge increase in performance.

Of course, with a sailboat, there is another wing to be concerned with and
that is the one below water - the keel. The keel or centerboard provides
the purchase against which the forces generated by the main sail work. A
hydrodynamically optimized keel and an aerodynamically optimized sail can
provide a really big propulsive force. Combine it with a sleek hull and the
boat can go far and fast.

Fixed keels and rigid sails increase the difficulties of operating the boat
but these can be dealt with.

Bill Daniels

"Dave Schneider" wrote in message
...
I'm not the person to ask why. However I understand that they point
higher
and are much more efficient. This concept isn't out in left field.
Remember the America's Cup catamaran with a solid wing sail?


"StellaStar" wrote in message
...
I'm building a foam core solid wing
for an iceboat/land yacht.

I'm curious...aside from the discussion of "luff tension" et al, what's
the
benefit of a solid sail?

My dad built an iceboat and I have vivid early-childhood memories of
skimming
along, face inches from the ice of the lake, going at what seemed a
terrific
rate of speed. Aside from the usual risk of getting clobbered by the
boom
when
it comes around, managing the sail didn't seem to be a problem for him,
and I'd
think it would give you more versatility, not to mention being easy to
wrap up
and tote.