I've been working through my boat's (1987 CC) wiring for two years now and I'm making more sense of it as I go along.
The first phase was to remove the existing panel & like stripminer suggests I ran two new heavy wires to the battery & switch to the new panel, then I ran another set of big wires to a second panel in the cabin on the port side.
The stbd panel runs much of the electronics, the instruments and lights, the port panel is for the fishfinder, accesory plug & in case I put in some tunes.
I used small panels I bought locally that are on a plastic base with all stainless hardware & use modern plastic fuses, they were pretty cheap.
This year I repaired some bad wiring, removed some unused wires & redid the bilge pumps.
I have one wired through the dash, no float switch just on & off. The other with a bilge pump is switched directly from the dash but the float switch is hard wired to the battery, that way you can switch the batteries off & still have a bilge pump on.
I still have some unused wiring & mysteries to figure out, it'[s an ongoing process.
doug