Frenchie,

Nobody is doubting your simulation and model testing experience and I don't doubt that to maintain 27 knots your calculations show that it would take 1.8 times the force required to maintain 20 knots. However, this doesn't say anything about it not being possible.

I think that Wouter's statement, that started this whole thing, was that a cat is capable of 30 knots. While perhaps it's unlikely that a beach cat could sustain 30knots, I think it's entirely possible in bursts of speed surfing waves.

Cheers,