Rather than a separate kit for the boat, I have a small (12") canvas tool bag that can go from car to boat (and plane when I had one). Has pliers, wire cutters, full set of sockets, open end wrenches, crescent wrench, wire terminals and crimper, ratchet screwdriver with multiple tips and a few miscellaneous items. Cable ties are handy and some stainless steel safety wire can be a great help.....cell phone and friends or towing insurance when all else fails.