Yes there is all sorts of foils but hydrodynamics has been around a long time now and there is an awful lot known about it. My question is and still hasn't been answered is the following. How much actual drag will there be created from a foil of 0.5 metre sq and how much force can a Spinnaker create in foward motion.

Maths boys, and there are a number of you who regularly post on this forum, get your calculators out and do the sums for us dummies and please don't go all shy on me, show us your credentials. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />