Fwiw, I read the Bernard Smith book "The Forty Knot Sailboat" many years ago and he seemed to think fat foils would work. But I'm not a rocket scientist, he was.
http://www.sailrocket.com/node/518"Some things just didn't fit into the high speed sailing forensics puzzle and we refused to neglect them. We had been constantly told how thin foils were the only way to go... and yet our big, 'fat', Mk1 foil had repeatedly hit over 50 knots. When we applied the theories and associated numbers that sent us down the path to superthin foils to the old Mk1 foil it showed that we would be very optimistic to even achieve 40 knots. It was obvious that something was wrong..."
