I just bought a couple at walmart. About 12 inches square. You can put batteries in them or use a 120 volt plug. The great thing it the transformer reduces the power to 12 volts so I cut the 120 volt transformer off and installed a 12 volt plug. Works great, quiet. Not high quality but for $20 works great
That derelict boat was another dream for somebody else, don't let it be your nightmare and a waste of your life.