One big problem you hit in over 20 knots of wind is the sea state. That will keep you from reaching the full speed potential as you run down into the troughs and climb the backs of waves. In France they have a long ditch filled with water where they do the speed records. No matter what the wind, the water is pretty flat there. I think a windsurfer came close to 40 knts. and the all out sailing speed record is close to 50...but you can't go that fast on a lumpy ocean. I don't know if they have ever run a cat down the ditch but it would be interesting to find out.

I once asked about the theoretical top speed of a Monster Cat like Play Station, the answer I got was about 60 knots, in flat water, but you can't find that much flat water and 30+ knots of wind to do it. They will do close to 40 in the open ocean.

In the right conditions (flat water, lots of wind) I'm sure you could get a Tornado with spin up to 30 knots or more.