[scook]

The recess in the cabin floor would seem like a good spot. I’d make a frame out of Ipe or some hardwood to keep them from sliding around and anchor them down. A few stainless screws through the frame into the sides of the recess should hold it down fine - with batteries in it, it’s not going to be very inclined to lift up.

There’s a drain hole to the bilge in case they leak (and you can rinse them off if needed). It’s as low as they can go so keeps the center of gravity low and I’d think you can drill a hole up high on the side of the recess and fish the cables along the side to the engine compartment in the stern (I’d pull a rod box and confirm that before doing any drilling). Before drilling, find a rubber grommet to protect the wires where they pass through the wall and drill the right sized hole for it.

Just thinking out loud but it’s what I’d be looking at doing.