World record for a human powered hydrofoil is 21.3 mph. https://en.wikipedia.org/wiki/Decavitator https://en.wikipedia.org/wiki/Decavitator 6mph looks a lot mor

World record for a human powered hydrofoil is 21.3 mph. https://en.wikipedia.org/wiki/Decavitator https://en.wikipedia.org/wiki/Decavitator 6mph looks a lot more reasonable in that context.