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Renovating T33 Hopscotch

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By Richard Usen
Posted: 2013-01-28T02:36:00Z
Porthole replacement

The boat has nine plastic portholes that have been on the boat since it was built in 1981. The plasticizer has been weathering out ever since and the ports were on their last legs. They needed to be replaced. As soon as the boat was hauled, I measured the area to determine if I would be able to replace the ports while the boat was covered. It appeared that I could and accordingly I ordered eight new ports from Beckson, who’d made the originals.  The difficulty of this project related to all the old Silicone that was attaching the ports to the boat. This needed to be removed in order to remove the old ports, but also to provide a clean surface to attach the new ports to the boat. Literally nothing will adhere to old Silicone, especially new Silicone. And, Beckson insists on using Silicone as most other sealants will attack the plastic of the new ports.I realized that there would be a lot of mess getting the boat as clean as possible.

To get the boat ready, I stripped the cabin sole and brushed on three coats of Epiphanes gloss varnish. This would give a new cleanable walking surface and protect the cabin sole during the construction to come.

The ports came next. Fortunately, Beckson still makes the same ports, so that the installation should be straight forward, I thought. Actually it is. The problem is removing the old ports and the Silicone residue that will impede the new installation.

The Beckson ports were bolted into place and caulked with Silicone caulking. The port frame has a flange on the inside that is fastened to the cabin interior which consists of ¼" of teak faced plywood glued to the 3/16" fiberglass house. There is a spigot molded to the flange of the port that goes thru the opening in the house and has a trim ring that goes over it and is bolted to the inside with 10-24 machine screws and barrel nuts. The flange and spigot are sealed to the boat with a generous application of Silicone caulk. To remove the old port, all this caulk must be cut away from the structure of the boat. Where the new port goes through the house, there is a generous application of caulk that seals the port to the house, and  more holding the trim ring to the outside of the port. To make the new Silicone adhere, ALL the old Silicone must be removed.

There is nothing elegant about the removal process. The trim ring comes off and then the port is removed from the teak facing inside the house, all without doing any damage to the cabin. I went through my tools and selected a putty knife with a sharpened edge, a small wrecking bar with a sharpened edge and a right angle bend for prying, and several flat blade screwdrivers for wedging. I then went at the first port. I removed the trim ring in one piece as practice and then attacked the caulk between the opening and the port from the exterior. After making a lot of cuts with the putty knife, I found I was able to remove much of the Silicone that was filling what looked like a groove in the opening in the house defined by the spigot, the flange and the side of the opening.

Next came the tricky part, separating the flange from the teak without damaging any of the cabin interior. I used a small hammer to drive the putty knife in between the flange and the wood cutting most of the bond.  Irepeated this everywhere I could reach except along the roof where there wasn't enough room. I then used my screwdrivers and the pinch bar to put some tension on the Silicone bond until the port started to free up. I've found that this works well with this kind of bond, whether Silicone, 3M5200 or other. Put it under tension and while stretched, work in a sharp blade.  I estimate this removal took the better part of two hours per port.

The next step is to remove ALL the Silicone residue since nothing will stick to it, including the new Silicone to come. I was told that there is no shortcut or solvent. And, in the process of scraping it away, you can scrub it back into the pores of the surface. It’s insidious and this is one of he reasons it has such a bad reputation on boats. I went at the teak surface first as it was the easiest to work on, being flat. I found that the wood was saturated and impossible to clean completely. There are (10) ¼"   holes for the old machine screws that need to be filled with epoxy to give tooth to the (10) #10 self tapping screws that Beckson recommends to attach the new ports. The opening in the house needs to be enlarged so that there is room for at least 3/16" of Silicone in the groove that you construct by enlarging the opening. This groove needs to be completely free of residue to avoid future leaks. So, I scraped the old opening as clean as possible before I tried to enlarge it. I also shaved off as much of the residue off the area under the trim ring. The residue cleanup took at least two hours per port.

I repeated the same process on the other seven ports. After I'd finished the first four ports, I seriously considered only doing four this year and four the next but decided I’d never do the second four later. Starting the fifth port was a difficult decision but I continued on. 

To prepare for the epoxy filling the screw holes, I ran a 5/16-18 bolt tap through the holes to both remove as much residue as possible and to roughen the holes to provide tooth for the epoxy. The epoxy process to fill the holes was the easiest part of the process. The problem with the epoxy was temperature. The boat is in Boston and this was December. I got all the holes ready and waited for a warm sunny 50*day.

And, shortly a warm day arrived. I capped the holes inside the boat with pieces of Gorilla tape so it wouldn't run down the teak and pumped in West System Six10, which if you haven’t tried it, is great. It's a two part thickened epoxy the comes out of the nozzle premixed which turned out to be both convenient to use and stiff like Vaseline and didn't run or even sag. Its also expensive but this is a boat. You can also thicken regular West System but this would have taken a lot of time to make up the batches necessary and I don't like working in confined spaces with the little West System hypodermic pumps. Bottom line, all the holes filled nicely by pumping the epoxy in while holding the tape against the hole with one finger on the inside and pumping and then tooling with a putty knife. The epoxy set up nicely in spite of the cold.

The next step was to drill the proper sized holes for the self-tapping screws. I drilled two holes in the center of the two fore and aft holes and screwed the port in place and used it as a template for drilling the other holes and then screwed the port into the opening.  That done, I carefully installed the other ports. I found that the Six10 is translucent and it was simple to drill in the center of the 5/16" epoxy plugs.

The next step was to mark the new opening for the 3/16" "groove". This was surprisingly difficult because pencil lead doesn't stick to Silicone residue either. I used a drum sander attachment on my electric drill. I found this tool at Rockler Woodworking and it is worth it’s weight in gold. I used a 1 ½" drum which cut nicely and left a nice clean opening with no residue. The teak and fiberglass in the opening eats sanding drums so you"ll likely need a drum per port but it leaves a much neater opening than the yard did with a Sawzall. Once the openings are cut and the ports replaced, the area under the trim ring needs to be stripped of residue.

At this point I got lucky. It turns out that one of the biggest secrets on the waterfront is that there is a solvent for Silicone; Toluene or Xylol. Accordingly I alternately shaved with my putty knife and scrubbed with Xylol until the house was clean enough for the new Silicone. To play it safe, I ran a 1" sanding disc in my 3/8” drill over the area under the trim ring. I doubt if it can be cleaned better than that.

All that was left was to caulk the ports with Silicone and glue on the trim ring. At this point, the ports would be held by the self-tapping screws and the caulk which will cure over time to act almost like rubber and hold the ports both mechanically and leak proof. After fighting with the old ports, I doubt if they’ll either move or leak. The old ports were beginning to crack but it took 33 years. I’ll never have to do that job ever again. 




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