So my stern bulkhead leaks. Found this out when we were doing rescue practice and the cockpit filled with water repeatedly--when I went to load the boat I found that the stern compartment had water in it. Filled the cockpit as a test to make sure it wasn't the hatch cover, and it's not. So . . . it's a WS Tsunami 140, less than 2 years old. It's not silicone used to seal the foam bulkhead in place--what is the name of the other stuff? Do I just run a bead around it on both sides and let it dry?