I've seen Troppo do it a few times with a couple of 32's at Yorkey's FNQ. The other day he got a nautical mile average of 29.27 knots on a wave board and a 4.2M wave sail at Green Island. This was way off the island and in "very rough water", but then the kid can sail

I had a hell of a time out there and gave up

I think if you're on open water, try the wave board, might give you more control and that'll give you speed.
My 2c, cheers