The boats in the water, twin big outboards, he's losing about 100L a week, we think they are rowing over and siphoning into cans in there tender, I made these to go in the filler tubes which are locked in the console, the rule is think like a criminal to stop them
Indeed, but they also have to suck the end of the hose to start the syphon......
siphoning is too slow, and the receiving tank needs to be lower. If the supply tank is underdeck then they are almost for sure using some sort of pump. Maybe one of the el cheapos that goes on a battery powered drill.