[mechhacker]

IIRC Thomas Goyard hit 41kts on the foil, but may not be "official".

The speed canals where they hit really high speeds on fins are in special areas that most people will never be able to experience that have no wind disruptions and are very shallow canals to keep the chop down like in Luderitz, it isn't an open water speed: https://www.youtube.com/watch?v=jt3DQNUJXkc

The races, which have fin and foil against each other, have been in open water state (more real world for 99% of windsurfers), and in those conditions fin vs. foil are very competitive, with foils pulling ahead in the turns due to a lot less resistance and better ability to get back upwind compared to a fin. There's been a lot of debate on even allowing them to compete in the same races as they currently are allowed. They can both do 30ish knots in the same conditions, with the foilers getting away with smaller sails. https://www.youtube.com/watch?v=jsUDkg2d5tE