Does anyone have this book?
http://www.amazon.com/The-40-knot-Sailboat-BERNARD-SMITH/dp/B0000EGOZDI'm not willing to pay $400. I believe it is out of print and now a collectors item.
My library had a copy and I read it just after it was published so my memory is a little sketchy. But,iirc, Smith wrote about "fat foils" and his prototypes were built of plywood.
I'm guessing these current ultra thin highly engineered foils are only one solution. Jus' sayin'..