Our Class A motorhome has a marine type hatch. Makes it easy to connect the electric and water utilities. But it leaves a large opening to those bays, and a nice pathway from a mouse to climb up (the water hose or power cord). I've made a couple of replacement hatches. One sized for the 50A power cord, the other for the standard white water hose. These have 15mm x 3mm magnets recessed into the mating surfaces. The parts snap around the lines, and to the new flange. No tools needed. Just as quick to remove. I still have a few updates to follow, which is why it's still listed as a work in progress.