My boat has been taking on water at times while underway but not at all when moored or anchored. I've been struggling trying to find the culprit since launching this year. I was convinced it was coming in the toe rail or a stanchion base although they didn't look that bad. Last week I pulled a bunch of screws and re-bedded them. Tightened and torqued. I thought I had it licked but then on Sunday, sure enough there was a puddle forming again down below. I reached into the cockpit locker to get a sponge and my hand got wet. I found a stream of water coming from the back of the propane locker. This locker was added by the PO inside the cockpit locker and it is vented through a short hose out the transom. When the boat is healing on port tack the vent gets submerged and (I know now) the propane locker gets water in it. The box is plywood with fiberglassed corners but the back of the box rotted out and the water was leaking into the cockpit locker. Since the propane is only for the BBQ I ripped the hole thing out and threw it in the dumpster. I'll just use the small, screw on canisters for now and make a rail mounting box to stow them.

So now I have an unused thru-hull fitting nominally above the water line but submerged at times while under way. I currently only have a manual bilge pump and I'd like to add an electric. I didn't want to drill a new discharge hole but now I have one. Should I use a vented loop and, if so, where is the best place to buy one? If yes to the vented loop, do I also need a check valve, the lift will only be about 2~3 feet (other than the vented loop). I assume a vented loop will be more fool proof than just a check valve. What maintenance is required on the vented loop, that is - do I need good access to it?