When that hole is determined to be an issue while the boat is out of the water. Usually a good hole in your boat is associated with some sort of way to properly let water in or out, such as cooling water for engines, sink drains, etc. I had heard some stories about the thru hulls on some Leopards being of an inferior grade bronze, leading to corrosion (well, okay, more properly known as dezincification) with associated horror stories (like breaking off part way across the Atlantic and having a gusher of icy seawater joining you on the inside of the boat.). So … being of a mind to not want to experience that, I figured I’d look into it. The ball valve on this overboard discharge had been stiff and reluctant to open (or was that close?) all the way. Let’s take it off and rebuild it. I put the pipe wrench on the ball valve and with the first effort, the thru hull snapped off adjacent to the boat’s hull, what would have been under water, of course. That is a 1-1/2″ diameter hole you are looking at. I was never so happy to see pea gravel beneath a boat rather than an in rushing stream of water. The rest of the day was spent disconnecting various plumbing parts and removing (read using a Sawzall) the remaining six thru-hulls. When spring returns to Maine in another ten months or so, all seven will be replaced with proper grade bronze thru-hulls and fittings. I’ll take it a step further and properly ground/bond each of them with a large copper wire leading to an appropriate electrical grounding point on the boat.