Death by Portholes

By Tom Neale, 7/23/2009


Tom Neale's logs have a new name and home on BoatUS Magazine. We know Tom has a loyal and devoted readership, so we wanted to share his tips and insights with an even bigger audience! For the latest articles, click here for Onboard With Tom Neale.

I haven’t had a root canal, but I’ve replaced my portholes.  I haven’t rebuilt an exploded transmission, but I’ve replaced my portholes.  I haven’t walked on the moon, but I’ve replaced my portholes. I haven’t leapt over a tall building with a single bound, but I’ve replaced my portholes.

A friend, hearing me moaning about the project, asked, “Why on earth did you do that?” I replied, “They leaked, you couldn’t see through them, and they wouldn’t open.”  “Oh,” he said, and that was the end of the subject for him.  But even though I had exaggerated just a little, it wasn’t the end of the subject for me.

Not all of them leaked. Just some of the more critical ones—like the one over my computer station and the one over the nav station and the one over my bed.  And most of them opened, except the ones I had glued shut in desperation to stop the leaks.  And you could see through all of them, but very poorly through some of them. This was because of crazing, hazing and, in general, a very long life.  My boat was built in 1975.  She had various owners before me, and I don’t even know all the places she’s been. I do know that she spent much of her life in areas of very high UV exposure such as the Caribbean, the Bahamas and south Florida. I also know that she’d experienced many storms; some under my watch. For any one plastic porthole to last all that time through all that use is not far short of miraculous.

But my boat didn’t have just any one porthole. She had sixteen.  She still does, but they’re all new now. Finding portholes that match the porthole cutouts on a boat over 30 years old is a bit of a challenge. We couldn’t find an exact match, but we found one close enough, so that only a little fiberglass grinding was necessary to make them fit. We got ours from Bowmar a division of Pompanette, LLC, (  Bob Touton, their product manager for hatches and portlights is a very knowledgeable and helpful guy.  He helped us find what would work, matching his current models with our pre-historic relics. We wanted to get stainless ports but had to settle for plastic (as were the originals) because, as is so often true with boats, we couldn’t afford what we really wanted. And if these plastic ones last half as long as the original ones (and they look like they’ll last much longer) we’ll be more than happy.

Tom Cutting Away 5200

Bob’s helpfulness went far beyond helping us to find a product that would work.  He helped us in the very worst part of the project. He could do this because he not only sells the things, he’s actually installed some. So he knows the awful ugly truth about porthole jobs: putting new portholes in is nothing compared to taking the old ones out. Especially if the x?;#^*  who put them in used 3M 5200.  On our boat, not only had 5200 been used, it had been used with wild abandon. The stuff really works, but therein lies the problem.

Bob gave us numerous jewels of advice, but the most important to me was to not to forget to celebrate each time you got an old porthole out.  Also, we had Dave Peresluha, a local very experienced marine craftsman to do the skilled work such as fitting and cutting and helping Mel and me to apply some intelligence to the removal part of the job.

Dave grinding using Shop Vac for dust

The first step in removing the old portholes was to remove the outside finishing rings. These, too, had been screwed and glued to the hull with 5200. If you read about jobs like this you know people talk about using razor blades to cut the sealant. There’s even a product or two that you can buy that supposedly weakens the 5200.  But I heard mixed reviews about these products and, besides, you can’t apply the product to 5200 that’s buried inside whatever it’s permanently affixing. I’ve used razor blades (in well-built quality box cutters) in the past, to cut 5200.  I had to do this once with an old windlass. But you have to be able to get the blade to the 5200 that you want to cut and the stuff keeps you from doing just that.  After numerous futile experiments, we solved the problem with the oldest most reliable set of tools I have: a steel maul and a pry bar.  I hammered the bar under any spot I could find where there was a little space between the ring and the hull and then hammered the wedge along the ring until, eventually, it started pulling loose. Then came the fun part.

Dave finshing salon

With a razor in a heavy duty box cutter we slit the 5200 between the old porthole and the hull, as much as was possible. This took a long time because cutting 5200, even with a razor, is easier said than done. And it was also a very dangerous job because of the razor and pressure that you need to use. After that we moved inside for more fun with the maul and the pry bar.

The old portholes had integral flanges which were supposed to be screwed or bolted into or through the hull from the inside. But the installers had glued them to the teak veneer which lined the interior cabin walls—using, of course, 5200. This had no structural significance as to securing the portholes. They should have been secured to the hull. There was no way we could cut or pry the portholes loose from this thin teak veneer. It would all have to be cut out and then replaced.

We cut away the teak around the portholes with an oscillating saw (great tool) and hammered the pry bar into the space filled with veneered plywood, and began slowly hammering it around the flange, tortuously breaking the grip of the 5200, an inch or so at a time.  As one person did this, another was outside with the box cutter, severing the white 5200 tendrils still mightily trying to hold the thing in place. After a considerable amount of prying and cutting, the porthole could be pulled out using old fashioned muscle. It took about an hour and a half to remove each porthole.

Tom’s Tips on Portholes

1. Many portholes have spigots (flanges) that extend out from the side of the cabin, over the deck. These can catch feet and shins and can easily be broken as you move stuff about the deck

Click Here for More Tips

Dave suggested we use Komatex to replace the destroyed old sheets of teak veneered plywood. It was a great idea. This material, (PVC foam sheets) won’t rot, provides some insulation, is light and easy to cut.  The white Komatex created an entirely new aura inside “Chez Nous.” Instead of the dark tunnel feel so common on older boats, she now feels light, open and airy inside. And of course, with new portholes that aren’t fogged over by age and that can actually be opened, it’s like we have an entirely different boat.

The holes in the hull had to be ground back slightly in some areas to fit the new portholes, and the cuts for the drain spouts had to be ground, but this was relatively easy with the oscillating saw and a grinder. We sucked up dust by holding the wand of a Shop Vac close to the tool. We used fast curing 3M 4000 to seal the new ports to the hull, trying to put it only where it was needed. We also screwed and through bolted them to the hull, in addition to gluing them. We tried to avoid getting any sealant on the Komatex.

It’s nice that “Chez Nous” is so much better now, and it’s nice to know that we’ve mastered another problem.  I just hope we never have to master that one again.




Copyright 2004-2009 Tom Neale