electronic rust proofing
It's called cathodic protection and yes it does! Ships use it to protect their hulls. It applies a voltage to the hull that counteracts the voltage that would be created by electrolytic corrosion. On ships, when used in conjunction with zincs, it is highly effective. I don't know of any units that are designed for boats, but if you find one, definitely a good idea for a steel hull! If you're electronically inclined, you may be able to design your own.