"Throttle" for electric motor?

I just got a small electric motor to put in my boat for fishing speed.
It is 72v with a peak of 38hp.

What is the easiest way of controlling the speed?
What battery setup will work the best? 12v or 24v, or does it not matter?


You should look at specialized “PWM” speed controllers for such motors.

They are very efficient because they send pulses of full-voltage electricity to the motor, and change the timing of the pulse in order to change the speed.

Without knowing the size of your boat, it is hard to recommend a suitable battery voltage.