Toroidal propellers.

[SteveMM62Reef]

Wondering who will be the first manufacturer to use the toroidal propellers, on their wave makers? They are Quieter, less energy is lost from side stream slippage, putting more of the thrust behind the propeller. BTW, I could swear Yamaha had these, for their Wave Runners, many years ago. They were much quieter at cruising speeds, with less bubbles and foam out the back. But, the top speed suffered.

 

[MoshJosh]

Maybe some 3D printer folks can just make replacement toroidal propellers for existing wave makers???