If I were in your position and having those types of issues, I would consider a complete rewiring job and I would re-fuse everything to make sure that all loads are properly fused. The reason for this is threefold. First, you'll stop blowing fuses and will get everything working properly. Second, after doing that, you will know and understand all of your electrical systems on the boat. Third, if you have an electrical failure on the water (and you will at some point in time, especially if in saltwater) you will know how to fix or bypass the issue. I'm on saltwater in the Chesapeake and Hatteras off shore. On my boat I carry a tool box and an electrical box that contains marine wire, fuses, connectors, multimeter, test wires, electrical tape, wire strippers, wire cutters, etc.