Marine Electrical Parts and Accessories. As a Marine Electricl shop, GTO Marine sees the biggest wear & tear electrical items on all types of boats. Salt takes it's toll afer a while and can penetrate wire, switches, connectors, and even breakers. We carry. When a wire comes compromised with corrossion , it continues to grow in size and resistance. Then the resistance will cause the wire (or switch) to overheat and thats when bad things happen! If your batteries test good but your chartplotter is complaining about low voltage- you have resistance in the circuit somewhere! Always be on top of your electrical system!