Stern Leak in a 410.
Donald, I read with interest your post. I have a Hunter 410 that had exactly the same problem. The hull to deck seal is done with 5200 and stainless steel bolts on 4" (?) centers. There were gaps in the 5200 that let water penetrate the joint. When the boat is underway the stern is pushed down allowing the water to be forced into the joint under high pressure. The water travels in a channel behind the fiberglass mat that covers the joint on the inside of your aft lockers. When the water finds a small hole in the mat (due to insufficient wetting of the mat during construction) it seeps into the locker. Try this test. Get thick water-soluble marker and draw horizontal lines inside the aft locker in question about 6" apart on the aft wall and on the locker floor before you sail. After or during the sail, water entering the locker will remove the marker where the water flows revealing the path and entry point. Don't be suprised to find the water seeping out of the fiberglass mat. The cure is not to caulk over or under the rub rail. I contacted the factory and they sent a factory rep to the boat. He ground out the mat in the locker, exposed the joint and recaulked from the inside. New mat was installed and both lockers repainted. This fixed the problem. It is important that you get this fixed. Water is entering your hull through the glass, if the problem is the same a mine (and I'll bet it is). Untimately, that water can cause glass delamination and blistering. Good luck. I am sure that other Hunters have this problem but haven't recognized it.
