On our boat we only use gas for cooking, one gas pipe from the gas locker to the cooker. Cooker has flame failure shut off. Pretty safe. Or you could have hundreds of amps in batteries, hydrogen gas given off when charging, huge expense and lots of heavy cables that could possibly chafe through. We always turn the electric off when we leave the boat even if its just walking the dog for 10 minutes. I am much more fearful of electrical fires than gas leaks and I would reckon that there are more car, house and boat fires caused by electrical fires than gas (And don't even mention solid fuel stoves) Anyway, you could always turn the gas off at the bottle overnight.