I was curious as to why sometimes an electric boat is faster than a nitro boat. For example I saw that very often I would notice a 3.5cc nitro boat doing a certain speed then a 4s electric boat could rival and sometimes beat the nitro boat. And many other instances like that. Then looking at the power rating for that giving 3.5cc I would see something like 2.8hp. (2088watts output) And an electric motor with less input than 2088 w would be faster than the 3.5cc nitro boat of a similar hull.

And if the electric motor is only 85 or 90 percent efficient how is it faster.

Then after studying more closely I realize some motors put out horse power greater than the input horse power. Example I have done research of the aquacraft 1800kv 3656 spinning a 45mm prop anywhere from 24000 to 25000 rpm underload. Well my 1730kv leopard 4092 is 8 mph faster than the aquacraft with the same 45mm prop on the same 4s and pulling close to the same amps. So imagine what the leopard is reving heavier motor which takes away from prop efficiency. And a 1730 kV on 4s.

But hear is where it gets interesting the ampdraw for me is around 42 amps on 4s with the 45mm prop. Voltage underload for me is around 16.1volts at the 42amps. That's is 676w input.

Now tell me if a 1 horsepower nitro engine can turn an octura m545 at 28000 rpm.

1 horsepower is said to be 746w. That's more than my input.

In fact a 3.5cc rated close to 3 horsepower will often require props around 40 to 42mm.

So power input in an electric motor does not always reflect power output.