After I cut this opening I sat there for 10 minutes marveling at the easy access and wonderful view of all the systems. I plan to place a battery box between the engine and quarter berth (partly under the berth) and it should be pretty easy to get the batteries in through this opening.

Some Project Details
To cover the hole I added some trim to the piece I cut out and put it back in. Insulation will be added to cut down on engine noise. To make the cut I used a jig saw with a good bi-metallic metal cutting blade, a battery powered reciprocating saw for the part I couldn't fit the jig saw in for, and a hand saw (basically a hacksaw blade in a small handle). The jig saw gave the best control and it is good to have a helper to steady the panel as you cut and keep it from flapping.

When I made the cut I left the bottom one inch of the vertical face of the panel to provide some stiffness. The cut went all the way forward to the bulkhead so there were only cuts made on three sides of the panel. The forward edge is a flange that turns inboard and had screws holding it to the bulkhead. After I finished the cutting I removed the screws by reaching through the OEM opening in the panel (it's for getting at the cockpit scupper seacock).

I will be building a battery box partly under the quarter berth and I'll use the side of it to provide some support for the bottom of the berth. The panel is pretty stiff as it is but they may not all be the same. Graham Bryan did the same mod on his 10M (#187) and found the need to add support under the berth.