I’ve been hearing about them for years, but it looks like this year you can actually buy a hydrofoil windsurfer. AHD is introducing the AFS 1. Check out the massive vent in the nose! And the Xtra-cool looking foil!
It seems to me that the big thrill must be in straight line reaching. Most articles and speculation I’ve read suggest that the hydrofoil means greatly reduced wetted surface, and therefore the potential for more speed. But I look at that foil, and there’s a whole lot of surface to it that is underwater. And a conventional board, when ridden back on the fin, doesn’t have much surface in the water at all.
I think the benefit is the smoothing out of bumps. The surface “carrying” the rider is no longer the hull bottom (which slaps into every irregularity on the water’s surface) but instead is cruising below the water like a submarine, where presumably le disturbances are far less. Smooth sailing (unless you broadside a bluefish.)
Check out the video (particularly if you speak French.)