The electrical requirements of todays' fishing boats have finally made us take another look at traditional layout and wiring. That's a good thing, 'cause we needed it. One thing I've not seen discussed is the 'common grounding' of multiple and independent power sources. That means the ground of a 24-36V system is connected with the -12V, not every battery. This isn't hull grounding, just a #14 connecting the proper battery grounds. The purpose is to equalize the various systems' ground potential in relation to the real ground of your big motor in the water. It solves a host of interference issues, reduces electrolysis on your l/u, and is cheap and easy to do.