Leaking Window Repair Update

I thought I would repost this and bring things up to date. In recent weeks, the windows that were repaired previously began leaking even worse than before we had the work done. I decided to fall back on the old saying, "If you want something done right, you need to do it yourself." So here is the history and an update of what we have done to make it right.

 A common issue with the Marine Trader is leaky windows. The previous owner of Beach House had the aft cabin windows removed, as well as the interior wood inside the cabin above the berths. New interior wood was installed, and the old windows and exterior frames were put back in place. But for some odd reason, the windows went back in and the exterior frames had a gap of at least a half inch between the frame and the window that was at least a half inch deep. A perfect water catcher and retainer.

We did a temporary repair early on because we knew we would be relocating the boat and we just did not want to deal with water leaks. We used Sikaflex caulking to fill in the space and seal everything. This worked for quite a while. This spring we decided that we needed a more permanent solution, but our work schedules really limit the time we have to work on these projects. There is a woodworker on site at Oak Harbor Marina where we are docked and after some recommendations from other boaters, we had him look at the frames and give us an estimate. He felt the repairs should be fairly simple, but this is after all a boat. We wanted the frames removed and a filler piece of teak epoxied onto the frames to fill the gap and to be sanded and formed to match the curves of the frames.

The removal process is always the most difficult part because you just never know if things will come apart in one piece of hundreds of pieces. We were prepared to build new frames if the old ones did not survive the removal process. The most time consuming part was removing the Sikaflex filler we so generously used for the temporary repair. Once this was accomplished, the wood frames came off fairly easily and, with one exception, in one piece. The aft facing frame did come off in four pieces, but none were broken so reconstructing them was not a big deal. The filler pieces were epoxied into place and fitted to both the frame and the gap between the windows. After dry-fitting showed everything looked good, it was time to re-install them.

One big concern was that by removing all three frames, we left open the possibility that we would have a leak somewhere that we did not have before. (That is exactly what happened.) The big question was, what would we use to seal the glass, fiberglass and wood that would be compatible with all three and allow for the difference in expansion and contraction between three different surfaces. Longevity was also an important consideration. From past experience doing lots of these projects on Sea Trek, we felt comfortable using Dow Corning 795 Construction Sealant to re-bed everything. We have never had anything leak that we have used this product on and that included, glass, Plexiglas, metal, wood, fiberglass and just about anything else. We also know that the black is UV resistant but the white is not, so black it was. The not so secret part of this is to be sure to use LOTS of sealant. It needs to fill every space and ooze out from every edge. Taping around the wood and cabin sides with blue tape also makes the clean up easier and gives a good finished edge.

The results looked great, however, as fate would have it, after everything had cured and we did a test with a water hose for leaks, we did find a couple of small leaks at both side windows. There must have been some spots where the sealant missed, and it does not take much. The tech was right back over to the boat, removed the frame, cleaned everything up and re-installed it with lots and lots of sealant. Just a few weeks later, we had a rain storm and both side windows leaked, and the leaks were worse than they had been prior to the repairs. We discussed this with the fellow that did the work and his response was, "gee, I don't know how that could have happened."

This time, I decided I would get this done right, do it myself, and never have to deal with it again. So once again, the outer frames were removed and inspection showed that indeed enough sealant had not been used to fill all of the openings behind the frames. I instructed the tech to NOT just caulk the edges of the frames, but to fill the space entirely between the glass and the frame. Well, even after doing it twice, he only caulked around the edges of the frames, leaving large gaps not bedded. I decide at that point, I would redo the entire area around the windows so no matter what happened with the sealant, these windows would never leak again.

Once the frame was off, all of the old bedding compounds needed to be removed, and the area around the windows had to be thoroughly cleaned, sanded and prepped. This took a lot of scraping and digging, since the integrity of the repair depended on the surface being free of old sealants. This left an uneven gap around the opening that exposed the inner core material and would allow water to enter the boat through the core should it leak. This would not do. The glass also had to be removed and,of course, it broke during the process.

The next step was to tape off around the exterior opening and the interior frame. I intentionally left the interior frame in place to be part of the improved repair. The gap between the outer fiberglass and the interior wood was filled in and leveled using West System Six10, a relatively new product from West System. It is designed to fill gaps and be fast-setting. It is a thickened epoxy that comes in a tube and mixes itself as it passes through the mixer tip. It is thick enough that it will not run into gaps and will allow you to tool the material to a smooth, even surface. It has a working time of about 42 minutes, and once it starts to kick, it sets quickly. It is easy to work with using a standard caulking gun. The only disappointment is that at over $20.00 per tube, the tube is only half full, so it does not go a long way. It took three tubes for each window. Once the Six10 had set up, the surface had to be washed down with plain water and a 3M pad. West System of any type will leave an amine blush on the surface after it dries and nothing will stick to it if the blush is not removed. No solvent will take it off, but plain water will. Next, the surfaces received a complete sanding using 60 grit sandpaper and using my new Fein Multimaster
tool. I really like this tool and it made this entire job much easier.

After the water wipe down and drying, my next step was to add a two inch strip of fiberglass cloth to cover both the inside edges of the interior frame, where the glass will attach, and the edges of the opening that had been filled with West System. We used West System epoxy for this also, wetting down the area the cloth would cover, then wetting down the cloth itself with epoxy. After carefully placing the cloth, it was smoothed out and any air worked out from underneath. The cloth would provide an additional barrier to water and would also keep the inner wood, the core material and the outer fiberglass from separating. The cloth effectively added a fiberglass edge around the inside frame to which the window would be attached.

Once again, after the epoxy had set for 24 hours, the washing and sanding process was done all over. This time to assure bonding of the bedding compound. The new windows were made at a local glass shop, using templates I made from heavy cardboard. A test fit showed they were perfect. The glass company also gave me small strips of a soft vinyl material to place around the glass to cushion it and to give me proper spacing. We gave a lot of consideration to what we would use to bed the glass itself. The general consensus from all of the glass companies was to use a marine grade silicone. So we decided to use a brand name and settled on 3M clear silicone. The silicone was placed around the edges of the glass and then the outside frames were screwed into place to hold the glass until the silicone could dry.

The silicone on the glass was allowed to dry for 24 hours and then the outer frame was removed. An inspection showed that the glass was solidly in place and completely sealed, not allowing any way for water to get to the inside. At this point, we wanted the window to be completely leak free and totally waterproof, even if we did not install the outer frame. A test with the hose proved we had accomplished just that. The next step was to re-bed and install the outer frame.

Once again, Dow 795 Sealant was used for the final bedding. The window itself and the outside cabin sides were taped with easy release blue tape to make clean up easier and to keep the finished edges looking professional. We finished this step as if the outer frame still had to hold out moisture. The space between the window and the outer frame was filled with sealant so that once the outer frame was screwed back in place, the sealant oozed out of every possible edge. Although this was not necessary, it was added insurance and made us feel certain that this would never be a problem again. Finally, the screw holes were plugged and the frames sanded so that the proper coats of Cetol could be brushed on, and our repairs were finally completed.

We have had a couple of really hard rains in afternoon thunderstorms with no leaks. Ultimately, time will tell if our repairs will meet our expectations. But we believe this is one issue that will not rear its ugly head again. Unfortunately, we have spent a fair amount of money to have the repairs done by someone else and the chance of getting any of it back is slim. I suppose the lesson is, we should do the work ourselves even if it means taking longer to get it done and giving up our weekends. Now to move on to the next project...


  1. Hi Chuck
    I am reading with interest your article on rebuilding the windows.
    I have just purchased a Cheoy Lee trawler with leaking windows
    I am looking for more information on the windows re what part leaks?
    Do you have to remove them and if so how do you do that or can you just reseal around the outside??
    Any help and pics would be appreciated



  2. Allan, I personally suggest that you don't just try and seal around the outside, it seldom solves the problem and generally will start to leak in a very short time if it stops at all. I am not familiar with the Cheoy Lee windows but based on other boats of that type I would recommend that the frames and the windows be removed. We did not remove the glass because our configuration allowed proper repair without doing that. In many other cases, this will not work well. The exterior fiberglass, core and interior surfaces of the inside edges should be sealed with a thickened epoxy and perhaps a strip of mat. All surfaces cleaned well and sanded. The windows and frames reinstalled using generous amounts of sealant. My preference as in our posting is the Dow 795. The leaks will come from gaps, even very tiny ones, between the frames and glass, into the core material and eventually the boat interior. So you need to think of your sealant as a gasket keeping all moisture on the outside of the frames, window, etc. Apply the sealant and never crank down on the frames, etc. to the point that you might squeeze all of the bedding out. we usually look for about the thickness of a dime as our rule of thumb. Care will need to be take if the windows are glass, depending on what original sealant was used. On our sailboat, the only way we could remove the windows was to break them out, but we would have never achieved a proper seal leaving them in place. It is a process that requires you to go slowly and step by step, analyzing the potential results for each method of repair. I hope this helps and answers some questions. Chuck

  3. Hi. Need to replace the windows on my 34 Marine trader dbl cabin, & was wondering why you went with glass & not Lexan?

  4. The windows we removed were glass so we replaced with the same. The glass was actually less than Lexan and we know from past experience that Lexan will not hold up as well in salt air and sunlight as glass and we did not want to have to do this again for another 30 years. Chuck

  5. Hi Chuck,
    We have a 1986 Marine Trader Sundeck. Window leaks of course. As I closely examine your pictures, it looks like you replaced the two-track sliding glass with solid glass pieces. Am I right and if so, how does this change your ventilation/comfort in hot climates? The two-track sliders I have are worn, and collect debris in the tracks, which make for good sponges for water. If you have replaced these, I'm really curious about it.

    Sand Castle

  6. Ben, We have not replaced the sliders, they are still the originals for our boat. There are only two, both in the main salon. One is over the galley sink and the other is behind the settee. We have not had an issue with rain collecting or debris. The rain does get in the track on the outside but quickly drains away. You need to be sure the small drains in the window frames are not clogged. If the felt material is worn, you can buy replacement strips from any glass company. Hope this helps. Chuck

  7. I noticed you replaced the opening windows with a non opening one.

    The solution to the aft window leaks on my Albin trawler was to replace the windows with an opening "plastic" (vinyl) window I had custom made. No more wood frames to varnish, and no more leaks.

    What I'm currently dealing with are the bronze windows that fasten to the INSIDE of the boat. Water has gotten in between the fiberglass cabin side and rotted the wood within. These things all leak, and look like they were designed to leak.

    Wanting to repeat my success on the aft cabin windows, I'm reading all I can find on these bronze nightmares.

    1. None of the windows we replaced or repaired were opening windows. They were all either replaced or repaired as solid pieces because that was how they were originally from the factory on this boat. The Albin is a bit different than the Marine Traders in that the frames inside and out are all teak, no bronze. But we did have this issue with our sailboat Sea Trek. The only fix is the remove the frames inside and out, fix the wood, seal everything like we did around the area where the window will go back in and then reinstall the glass and frames. I feel for you. Chuck

    2. Chuck,
      Really enjoying your blog. We are starting to look for an older trawler and are interested in the Monk 36. Any comments on this make?
      When you soak an area with epoxy do you try and dry the core first?
      Thanks for your great blog!

    3. Steve, the Monk 36 is a great boat and if we could have found one at a reasonable price we would have snatched it up. We have friends that had one and they loved it. As to the epoxy, it is very important that everything is completely dry before adding the epoxy. Sometimes this takes some work and patience but it's important. Good luck with the search. Chuck

    4. Thanks Chuck!
      Does the Perkins 6354 135hp that came in the older ones give you any "heartburn"?

    5. Chuck,
      Sorry if I have already sent this. Google acct seems to be giving me fits.

      Did you consider using a dinghy motor mount similar to a sea wise that allows the motor to rotate 90* and Hang vertically when the dinghy is on the swim platform? Does the dinghy on the swim platform cause you any concern in a following sea?

  8. I can't speak for the Perkins in any of the Marine Traders but all of the Perkins I have worked on in the past were great engines. We had a 4-108 in our sailboat.

    As for the dinghy outboard, we have considered the mount that tilt2 90 degrees and would let us keep the outboard on even when the dinghy is tilted up on the swim platform. We may install one at a later date but for now it isn't a problem. We have had some pretty good size following seas down the Chesapeake and we never felt any concern with the dinghy on the stern. I suspect if they were large enough it could present a problem although we know lots and lots of trawler owners with the same set up we have and no one has reported any problems to us. Our philosophy is to stay in port if the seas are that big no matter what the direction. Hope this helps. Chuck

  9. Hi Chuck, We are looking at a 1985 Tung HWA sedan trawler. There is extensive leaking under a few windows and with one the inside wall is damaged all the way to the floor. Wondering how expensive that is to fix? "I have a serious crush on this boat"... :). Also, it has a Perkins 120 HP motor with 1200 miles on it. (We are new to the boat world) How long do these motors last? Any help is appreciated!!

    1. Cathy, There is no way to accurately estimate the cost of repairs without a complete inspection and estimate. You will need to have a good service company come on board and look things over. The Perkins should last a very long time if it was properly maintained. I assume you meant it has 1200 hours on it and that is not much at all. But the boat needs a thorough survey by a qualified surveyor and the engine needs a complete survey by a qualified mechanic in order to determine the exact condition of both. Sorry I can't be more helpful. Chuck

  10. Chuck and Susan,
    Great blog! I do have a question, what type of wood do you recommend as an interior replacement for the walls of the house? Just acquired a MT 36' Europa and the window water damage is worse than I thought.

    Thanks for all,

    St. Johns, FL

    1. Roland, You have a few choices. The interior is a thin plywood so you can find a source for teak plywood and use a matching varnish. Another option is to use an exterior plywood, don't use treated, and cover that with a teak veneer and varnish. A third choice is to use an exterior plywood, stain it to match as close as possible and varnish. In all probability, any of these choices will not match perfectly. Good luck. Chuck

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