Had some 50 degree weather, so drove to the boat. While I was there, took some pics of my engine box mods, which I made probably 7 or 8 years ago. Struggling with removing the whole box just to change the oil convinced me there had to be a better way. This is on my 97' C36 Mk II, not sure what might be different on other years. Although it's been awhile, I remember fairly well how I went about the project.

I completely disassembled the box to bring it home. If you turn it over, each panel has a zillion screws attaching it to cleats. I recommend using an electric screwdriver, unless you want your arm to look like Popeye's. Once removed, the panels come apart fairly easily. I also removed all the trim around the top; dug out the bungs and removed the screws and the trim came right off. Good idea to make index marks on each matching edge to make sure everything goes back together.

I do not have my original measurements and didn't have time to take them today. If you look at the picture of the closed box, you can see the marks left by the ladder. I made the top lid so that the ladder would hold it shut. The front is held shut both by the ladder and a turnbutton (probably not needed). I made the front hatch large enough to remove the oil filter and waterpump impeller, change/adjust the belt, etc. I can change the oil via the top hatch.

I cut the hatches out by turning the piece over, and marking it on the bottom. For the top, I made the side cuts with a circular saw, fitted with a plywood blade, using a guide to get a straight cut, and being VERY careful to stop at the mark. This leaves about 1/2" or so to be cut on the good side, which I did with a back saw. For the cut across the back, I made a plunge cut with the circular saw; best practiced on some scrap first. All cuts on the front were made with plunge cuts, again working with the good side down, finishing each cut with a back saw.

The cuts could probably be made with a sabre saw, but I've never been good at making accurate cuts with one. Circular saws are not my favorite tool, but with lots of practice on some scrap, everything went quite well.

I used iron on plywood edging on all exposed edges, both on the lids and the box, stained teak.

To provide a stop for the hatches to sit against, I bought 1" x 1/8" aluminum strips at the hardware store. Cut to length to fit inside each edge of the cutouts, leaving 1/2" exposed for the hatch to sit on. Pre-drilled and mounted with 1/2" screws. Then applied weather stripping to make sure of a good seal (for soundproofing). You can see the aluminum strip along the top edge in the closeup where some of the weather stripping has come loose (have to fix that in the spring).

I added 1x1 cleats along the bulkheads and floor on the inside of the box, to provide additional support for the top/front and to seal against sound leakage. The box is held in place on the inside, with the rubber clamps used by Catalina to hold the engine cover in the aft cabin. Don't remember the brand.

Top hatch attached with hatch hinges, front with removable hatch hinges, both from West Marine.

Along with adding sound proofing, which I did at the same time (major, major improvement) and the ease of access, this is one of the best improvements I've made to my boat. I have not removed the entire box since making the modifications.:):)