>>13972504>that means the water applies more torque on the blade, slowing it downThe ratio of thrust to torque is higher when propellers are in liquids of certain viscosities like water. It's like swimming in water vs swimming in air. You get more thrust for the torque your arms apply. Fluid friction is not linear though so if you go real fast you have waaay more friction and slow down. That's why an airplane will go 250 mph on a certain power engine but a boat can only go 1/5th of that. If water was frictionless and cavitation wouldn't destroy a propeller then a boat with a water propeller could move faster than an airplane.
