The starting battery for my outboard was in the already crowded lazarette, and the mounts were rotting away. I wanted to add a house battery as well without adding ALL the weight to the port side. I needed to be able to get to the batteries easily, so under the cockpit was out. I finally decided to convert the cockpit ice chest (Since I never used it anyway) into a battery compartment. This gave me easy access and allowed me to keep the existing hatch cover.

This involved a LOT of fiberglass cutting, so if you do this USE A RESPIRATOR!

First I unhooked the drain line from the chest. Then I cutout the box about a half inch under the rim. The rear bulkhead wall of the starboard side berth also has to be removed. (It is in the way, and is a part of the ice chest itself.) After it is gone, I took a large piece of cardboard from a box I picked up at U-Haul and traced an outline, refining it until it was a snug fit. I then transferred that to a piece of 1/2 Birth Plywood and cut it out, altering it as required to make it fit. I made a bottom deck for the compartment out of some 3/4 plywood I had lying around. This piece was coated generously in fiberglass resin and put into place. Another piece of plywood was glassed into the original stiffener and to the new compartment deck. The entire compartment was them covered in fiberglass cloth, covering the entire surface of the compartment interior. This separated it from the cabin interior and bound it to the remaining walls and the hull. A little grinding to remove the rough spots, and it was basically finished. I screwed in the strap retainers for the battery boxes, the put in the original Starting battery and the new Deep Cycle house battery. I then added a battery selector switch for the motor (It has an alternator and can charge one or both batteries when running) and a regulator for the solar panel I used to keep them topped off when not in use. Then I ran cables to the new electrical panel, and this part was complete.