I have an 86 31, Lawrence, and have spent way too much time down in that locker. You can let yourself down in there, but it's a squeeze. The starboard locker contains the fuel filter, fuel tank, CNG tank, fresh water pump, and fridge compressor. It also has plumbing lines and control cables from the pedestal. To the rear, the starboard locker actually joins the aft locker. I think the stock setup had a single bat in the starboard locker, and 2 house bats behind the engine. I went with AGM 31s, which are larger than the stock 29s, so I elected to switch them, with the cranking bat behind the engine and the 2 house bats in the starboard locker. To offset some of the weight [the boat is decidedly starboard heavy with fuel tank, galley, head and bat all on one side], I put my Freedom 20 in the stowage area under the port aft berth. If I know which wall you mean, it separates the starboard locker from the aft berth.