In 1984 I became interested in hydrofoils and started to research their design and make my first hydrofoil based systems. The first up was a foiled centerboard  for a 40 pound "Sailboard Brand" windsurfer. It had a main foil section with a 12" span and a secondary foil section 4" wide and 8" long just behind and above it. I regularly used an 8.8 meter sail in up 30 knot winds. There was a regular fin at the back of the board. This foil would negate the weight of the board and sailor and allow smooth travel in small chop. It was made out of plywood and oak covered with unidirectional carbon. Very light and very strong.