Safety idea (from my local sailing school / chartering place):
One can swap the latch fitting on the locker so the hinged part (hasp?) is on the hull, locking ring (staple?) on the locker. That way if the locker slams closed on you, the hasp cannot fall onto the staple and lock you in.
A related thing is to have a snap-hook to use to keep the locker latch closed (e.g. if knocked down), also tied to the staple (ring). That way you can't lose it, but better, since it will now be on the locker lid, when the locker is open you can (assuming proper length of securing line) use it to clip the lid to the lifelines, again reducing chance of getting stuck.
Though having a friend present just in case seems best; at a minimum they can regale you with appropriate commentary while they drink beer and you curse doing repairs in the confines below
Question: has anyone here added a gasket to their cockpit lockers? I believe this may be recommended (required?) by some singlehanded sailing societies, which also require rapid-draining cockpits. I am thinking of adding these (would take the place of the bumpers; mine are also decaying); any advice appreciated on best ones to use and best way to secure / install gaskets to fiberglass.