Yank it all out, then rebuild it one circuit at a time. Be careful to label everything first - I suggest a simple and inexpensive label printer
- it can save you a lot of headache latter on.
Start at the bottom level, i.e. getting power from the battery switch to the panel. As Mtiempo's photo shows run everything to a strip first, do ring terminals on every input - and that is where your label should be, on the bit going into the terminal.
From the terminal take it to the panel's breaker switch with just enough left over for a drip loop and a new splice (just in case). Don't forget to add in extra wire so you can run nice cable runs and tie wrap it up neatly.
If you wind up replacing any of the wiring my suggestion is you go up a size over the recommended gauge. It might be sacrilege, but I use the same size for everything so I only have to get two colors, hot and ground, one big spool. I specifically don't worry that I'm not using ABYC recommended colors for my lighting, equipment, yada yada.
If you plan it out it's not that big a project. If everything is run to a strip and properly fused then a circuit diagram is not needed - you know where it's run to and from.
Doing a rip and re-do allows you to organize the panel in a way that makes sense to you (i.e. lights in one place, equipment all together etc.) Take the opportunity and make it so.
I don't know what your budget is for this - but if it has an extra couple hundred it might be a good time to get a new panel with the proper sized breakers where you need them, complete with digital volt and amp meters and LED lights next to the switch. My panel runs in the 500 buck area, Blue Sea, custom laid out to how I want it.
My suggestion is once you get power to the panel and a ground bar properly wired you should do your internal lights next, then the boat's running lights.
If you are going to do this invest in a good set of tools for stripping and crimping. Cheap stuff just costs you in time and effort during the project and later when you are tracing down the inevitable bad crimp.
SailNet user MaineSail at
Compass Marine "How To" Articles Photo Gallery by Compass Marine at pbase.com has a lot of how to's and posts here quite frequently on proper tools and methods. Use the search function here to find them.
It's easy to get in over your head, if so hire a certified wire jockey and have them visit and offer guidance. Bad wiring and electrical fires are one of the most common reasons boats are lost. Make sure you do the job safely and wisely. Have a fire extinguisher close by any time you energize the circuits to test.