Very cool videos and a great idea!
Would be interesting (for a next time) to include a windsurfer.
Would a good catamaran or trimaran be any competition, or would they not stand a chance?
Foilboarding (Carafino etc.) would also be an interesting contender.
I think that a foilboard, where the riding trim is controlled by some sort of wand like on a moth, might be the ultimate speed machine.
Very impressive how that moth kept its speed through the tacks.