Back in 1982, a friend that attended Cal Poly Pomona with me in mechanical engineering selected as his senior project the design and fabrication of a set of foils for his Hobie cat. He cut the upper surface to a pure arc since that he felt it would be adequate, but also because it seemed easiest at the time. He used a very large barrel fixture and mounted the foil blanks on it and turned the whole ensemble on a huge lathe. As I recall, in the test phase he was able to get it foil-born, but anything that disturbed the boat in pitch required a lot of luck to stay up. He used some type of float on a lever arm to automatically adjust the foil pitch.
Seems like forty years and cubic dollars has advanced the concept a bit....
Dave