[Tiara 3600]

I haven't hooked the boat to shore water supply until recently at a slip. I notice the bilge pump come on a few times & thought that was strange since I usually don't have much water in the bilge. After the weekend, I noticed the boat listing to the side where the water hookup is. I'm thinking there must be a leak in the water line somewhere and the water is built up & only coming out slowly. Wondering if this has happened to anyone else?

I'm guessing the water will continue to leak out of where it's trapped, eventually but, I have to pull the boat out of the water next weekend. I guess I should plug a solar panel into the system to keep the batteries charged so the bilge pump can continue to pump out the water? Any thoughts on this?