Sails

I've been sailing for 40+ years - raced dinghies up to boats across the Gulf of Mexico and this is the first time I ran into a clear (believable) explanation of how the sails work. Airplane wing - it takes longer on the curved side - Bernoulli - low pressure =s lift. I'm an engineer and have lived with that forever - but although a sail may be shaped like the upper edge of a plane's wing - it doesn't have any thickness - therefor there is not much difference. How does THAT explanation account for the lift? As an engineer I can only say Thank You Derek Harvey for a better and more believable explanation (I hope your right!). His explanations of what adjustments to make to the sail under varying conditions were most helpful. I only wish he had made an easy reference sheet. I also found it useful to know why then sail makers do the things they do. I will consider it a valuable tool in helping me decide what boat, and what sails to buy in my current search. Not only do I recommend it to others I am buying a second copy for my son who has just made the varsity racing team at the Coast Guard Academy. `nough said.