Welcome to PB.

The old hand held cranks work well but often kill the fish. Don't stick your hand (or anything else) in the water when cranking. Note it is not legal to crank up fish. Kidding of course.

The control units on electrofishing equipment are complex and the boats have a continuous kill switch for a very good reason. A lot can go wrong with electricity and water plus the fish are not real fond of the experience.