: Hi Charlie,
: A tall narrow sail on shorter hulls is sometimes necessary, for example,
: tall-banked rivers where a low, broad sail will be wind-shadowed. Chinese
: river junks used this aspect rig.

: Most sails now have the panels cut by CNC, and the shape of the sail worked
: out on computer using NACA profiles to get the optimum shape of the
: complete sail.

: Racing sails have almost no stretch in any direction, their shape is as fixed
: as possible. Mylar reinforced sails have no stretch, when they reach their
: limit, they tear. Rather catastrophically, which is why their usable
: lifespan is kept to a few races at most.
: Cruising sails are primarily of Dacron for its low stretch, but it does
: stretch and lose its shape over time and use.

: Using a non-stretch material for a sail just means you have to develop the
: shape through curved cuts and joins. Using wooden NACA templates makes
: sense for a prototype to find the best ways to cut for shape.
: Wrinkles wouldn't be a disaster either, unless they were big enough to make
: enough slack to flap when sailing. The material would eventually give way
: at that point.

: Hope this helps,
: Mike Savage
: South West Cork

Thanks for your testamonial, Mike, but, no thanks. I'll wait for John Monroe to verify the ease or difficulty of turning out a blue tarp sail with an NACA profile.
The guy that designed my little boat recommends using used sailboard sails as an alternative. He'll even come up with the proper change in mast rake if someone wants to go that route.