If you have added ports to the hulls check them. I had a similar problem with my P16, I did not think the ports were the prob, but when I took them off the silicon had broken down even though it looked intact befor I removed them. I heard that the best way to install them is to silicone thim to the boat, but only slightly tighten the screws. Let the sealant set up and then tighten the rest of the waw so the sealant can form a gasket.



Check the drain plug flange sealant also.



Just a thought.