Here is a video that shows what it's like to do over 50knots peak and unofficially break the Australian 500m sailing speed record

[1]

And here you can read all about it.

sailrocket.com/node/576

Lots of power to spare, BUT:
Previous runs 6 months ago-
Conventional fin with fences- 50 knots
"Supercavitating fin (shaped like an axe) - 50 knots
Above fin cut in half- 50 knots

Looks like a limit for submerged fins?

My guess is that they are probably the best "standard" foils so are capable of hitting the foils' limit. Conversely, we know very little about supercavitating foils, so likely to not be all that optimal.

In either case, drag goes up exponentially relative to speed and we know that at about 50-55 knots, we get cavitation anyway which increases drag dramatically. Maybe it is as simple as, they are getting exponential drag due to the hull.

I dont buy that they have plenty of power... we know that power-boats need *significantly* more power once they reach 40+ knots. Sailrocket are probably just running into a power-wall... *relative to the power required to overcome the drag*.

Of course they could get more power simply by going in strong wind... Obviously they dont want to break the boat just yet. I can see this model boat doing very well -> maybe once they get it dialled in, they will push it harder.