Their first prototype, shown above is literally just a trampofoil with an added seat and pedal powered prop. They did manage to take it a step further though and came up with a second prototype ...

A propeller moves it forward, like a boat. Top speed ... The Manta5 is a hydrofoil water bike. It's powered by a 400-watt motor. You can pedal on a river, lake, or ocean. Here's how it works.

Most famous of these is probably the toroidal propeller that made waves a while ago, mostly in the field of flying drones, but commercial toroidal boat props exist too. Test results of the ...