How much power does an electric surfboard/efoil need? 16x off the shelf ebikes combined, 20k rpm!

Propulsion system statistics of the DIY efoil. At full throttle the motor is doing 20,000 rpm, that's 333 turns per second! Motor rpm is reduced with a planetary gearbox down to 4000rpm for the propeller, while the torque output is around 9.5nm at full speed. The prop torque can go up to 11.25n.m while rpm can go up to 5000 (25000 rpm, 2.25nm at motor) more speed is possible with a higher voltage battery!