[BP-Revo]

Well, in a boat, you have to factor in water resistance and the prop and stuff.

If you are running a small prop, you want more RPM, but if you have too much RPM on a small prop, then it sucks air and you lose power because its moving too much in a small area.

If you are running a large prop, you want a little less RPM, but too little causes slow top speed.

So, you want to find the perfect balance between a prop and motor.

Also, if you want top speed, you want a motor with more KV. They generally have more top end for higher top speed. You could gear up a low KV motor, but that usually results in less acceleration than a low KV motor geared properly for the same top speed. Then again, a high KV motor has less run time, because its more powerful.

So, my suggestion is run a medium sized prop and get a medium KV motor, thats probably the best setup, as a prop spinning at high RPM gives better top speed than a large prop at lower RPM.