Regular readers of this blog likely remember hearing that ocean sailing is hard duty for a boat. The constant motion as the boat rises over the front of a wave only to crash downwards into the next one, all while corkscrewing in a cross-swell, puts enormous stresses on the hull and everything attached to it.

Telltale sign of a leaking port- a small drip of salty water on and below the port frame

The result is that there’s often something to fix after a long ocean passage, and the recent trip across the Atlantic is no exception. The opening ports in the side of Oso’s coach roof started to drip a bit when waves would wash over the deck. We have a very low tolerance for water, especially the salty kind, leaking into the boat, so one of our first jobs once anchored is to stop the leak.

After removing the leaking port we removed the original gasket and completely cleaned the surfaces

Some people will address a small leak like this by dabbing a bit of silicone on the outside of the hatch frame, but in our experience it’s a much more reliable, and much longer lasting, fix to remove the port, clean up all the old sealant, and then reinstall with fresh sealant. It takes longer to do it this way, but it means that the next leak won’t come as soon – so, theoretically at least, the overall time spent working on the hatch is reduced.

Applying butyl tape to form a new gasket seal

First step is to remove the port from the hull, and it was a pleasant surprise to find that the port was installed with a rubber gasket, with no sealant at all. That means that it was very easy to remove, and equally easy to clean the mating surfaces on the hatch and the side of the hull.

Part way through the project a big squall rolled through and it started raining in the boat. Luckily a towel draped over the opening kept the majority of the rain out and like many tropical squalls it passed by and was sunny again in a matter of minutes

Since we don’t have access to new custom rubber gaskets for our ports, we used the next best material – butyl rubber tape. This flexible tape sticks tenaciously to make a watertight seal, but never hardens so it’s reasonably easy to remove if (when?) the hatch starts to leak again.

Ready to reinstall the port with new butyl gasket

After applying enough butyl to ensure we’d get a good seal, but not so much that the port wouldn’t stand proud of the hull, we carefully aligned the port and pressed it into place. Over the next several days, we slowly tightened and retightened the screws to compress the butyl until it squeezed out everywhere around the port frame. A quick cleanup of the excess rubber, and the hatch is watertight again.

Until the next passage…

Excellent butyl squeeze out around the entire frame. After this.photo was taken, it was just a matter of a quick clean up of the excess butyl and the project was finished