Ideas for a adding main battery shutoff

Since I work in the marine industry, I tend to mount battery switches in dry places to advoid corrosion. I can think of no place worse that on the front of a TT, getting pounded by rain as you travel down the road. Eventually it will fail, and there are really no completly "waterpoof" switches. I like the Blue Seas brand. I mounted a dual battery switch next to my converter. Easy to wire, just have to remove the positive wire from the converter (black 12V wire) and attach to the switch, and then add a wire from the switch to converter. I have two battery banks, so I installed a dual battery switch. Blue Seas has a nice single bank switch with a removable key, that is the one I would buy. See pic. The switch mounts "though" the wall and sticks out no further than the converter.