Total force resisting the forward motion of a boat at a speed

[sparkle123]

Problem:
A boat powered by an engine rated at 100 kW can reach a top speed of 70.0 km/h. What is the total force resisting the forward motion of the boat at this speed?

I don't know which equations to use :(

 

[kjohnson]

Well if I am correct, then at that max velocity the engine is using all of its 100kW of power to maintain that speed. So you know that to maintain constant velocity the power output of the engine must be equal to the resisting power of the water.

Now if the work done over any distance 'x' by the water is F*x, then what is the power?

 

[sparkle123]

Got it! Thanks for your help!