We found a simple, and cheap, solution for our leaking Lewmar portlight windows. It only took us over a month to get the order for the parts right.

We found out that all of our port light windows leak when we were stuck in a storm in Kingston. Most of the water seemed to be coming through at the latches.

July 24 Port light dog

After some research we found that these latches are called dogs and have a rubber o-ring that compresses against the Plexiglas to seal out water. It’s common for these o-rings to disintegrate over time and start leaking. This was possibly the cheapest and simplest solution so we decided to replace all the o-rings first before exploring more expensive fixes like pulling the entire port light out and re-sealing.

Using an thin knife and thin screwdriver I was able to pop the center plastic cap out of the dog and unscrew it from the Plexiglas.

Dog disasembled

Taking a closer look at the o-rings we could see they needed to be replaced!

Damaged O-rings

After a few failed attempts in ordering o-rings online we finally found some that worked. I was surprised how difficult it was to find these. We tried to get silicon ones from Amazon but the original order we received were the wrong size. Measurements are not consistent either, when ordering be careful that sizes are either inner diameter, outer diameter, thickness or some strange code I haven’t figured out. I tried to find some through Lewmar support but they directed me to a third party called HatchMasters that sells kits for $7 for a single port light. This was going to be too expensive! We bought a pack of 50 o-rings for $12 from Amazon. And bought a container of silicon grease for $15.

o-ring label

I read somewhere that the inside diameter is 12mm. These may be slightly too small but I like how they stretched snuggly into place.

After removing all of the dogs from the port light we cleaned up all the dried up crud around the holes.

Port light dogs removed

We setup this simple cleaning station to wash everything.

Dog Cleaning

After drying everything we added a bit of silicon grease to the dog where the o-ring sits and then screwed them back onto the window. Just be aware that there are two different types of dog. I called them an “L” and a “Backward L”. The bottom of the Ls need to point toward each other. When you screw them back on be careful of the tension. Over tighten and you won’t be able to turn it, under tighten and it will probably leak.

We put everything back together, popped the center cap back into each one and then tested it out with a hose. And even with direct full force spray they stayed completely dry! Gotta love it when you can fix something for under $30!