Luiz, this could help explain why the "J" (or "L") shapped foils would be an advantage. The lifting portion of the foil will be located deeper below the cycling flow of the wave. I remember that Hydroptere has angled lifting foils that lift from their length to the surface of the water. I would think this angled foil would be much more suceptible to wave flow influences than a deeper J or T shapped foil.