Editing Electric boat (section)

===Speed controller===
To make the boat usable and manoeuvrable, a simple-to-operate forward/stop/backwards speed controller is needed. This must be efficient—i.e. it must not get hot and waste energy at any speed—and it must be able to stand the full current that could conceivably flow under any full-load condition. One of the most common types of speed controllers uses [[pulse-width modulation]] (PWM). PWM controllers send high frequency pulses of power to the motor(s). As more power is needed the pulses become longer in duration.