My 'new' old boat

[1FASTLASER]

Mr. Robertme,
Can I suggest a solution to a old problem. Before you really get done rewiring make it easy on yourself. If only costs a few dollars......around 20 right off the top of my head. Run 2 wires up to your console (underneath of course). One of them goes to the negative side and becomes a central port for all connections now and the future. The other being one connected to your positive side of the battery and the other end going to a fuse panel. They can be had for around10 bucks or so. Now you only have the engine wires and those 2 cables running up through the maze AND you will have an easy access place for future hookups or a easier access if something goes wrong. Electronics such as your depth finders should have a 3 amp fuse and NO MORE. Everything else will be using a 10 amp unless specified otherwise form the manufacturer. Trust me this is the way to go.
The fuse panel will have a strip that is connected at one end and have a larger terminal for the power wire. I STROBGLY suggest using what I use. 6 gauge wire for both the neg. and the positive. It will carry sufficent amps to the negative port and positive fuse panel.