Maxum made the cleats for those sole hatches by screwing from the top. So when you step on the hatch, you're entire weight is suspended form the screw threads. It's a poor (lazy) design. What I did is remove one screw, drill through both the sole and the cleat, then through bolt with 316SS bolts, washers, lock nuts and a counter-sunk flat head bolt. 8 total (2 for each side).
A drain plug can be installed. I'd hog out some of the transom wood, and back fill it with thickened epoxy before installing the through hull.
Marine generators are all problematic.
fuel burn...LOL!!! Well, there's always golf