The boats bilge pump float switch. Todays boat wiring is one of the most difficult problems youll run across due to requirements of the numerous accessories.

Chrysler Outboard Wiring Diagrams Mastertech Marine
Typical boat wiring diagram. Equipment coming off a switchboard or circuit panel should be straightforward to trace. An ordinary auto battery would do for starting and lights but for running a radio and other electronics something with a little more of a deep cycle capacity will be needed so the battery doesnt go flat while youre fishing and listening to the radio and leave you stranded when you try to. Its pretty standard in boat wiring to bypass the main battery switch for one thing. When you make your own wiring diagram use very large sheets of paper for clarity. Example of a draft wiring diagram for a simple boat. For people just getting into boating or for those who have been boating for a while but have managed to avoid the electrical side of things the 12 volt dc direct current systems aboard most boats dont have to be daunting.
The battery should be a combo startingdeep cycle battery usually sold as a marine battery. For the last several weeks i have been chasing a problem that has been causing me to lose sleep at night. This way even if your battery switch is off if your boat starts filling with water the pump will still kick on. Id rather have a dead battery than a swamped boat. Most boats will have positive and negative busses where area wires come together. Full parts list below amazon electric section.
The back of a wiring panel can look pretty daunting but remember youre only troubleshooting one circuit at a time. After many decades of troubleshooting and repairing boat wiring issues ive become pretty darn good at figuring things out.