Pearson Yachts Forum
Pearson Boats - Common Systems => Ports & Hatches => Topic started by: Libations Too on May 14, 2015, 09:20:33 PM
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After avoiding this project for a couple years I decided 2015 was the year to tackle the job of resealing and rebedding the two starboard fixed ports on Libations. I am now finished! Many thanks to Selene, Alma, Sea Haven, and Dolce Vita for their helpful comments and suggestions.
My project summary is here: http://rollinscs.com/boatpages/projects2apage.htm I have tried to gather into one place the helpful tips, comments, and previous project summaries that I found most helpful.
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Richard!
Thanks soooo much for documenting this!! I plan to go forward now that I see it. The powder coating is a fantastic idea!!
Again, great job!
Now I just have to finish off my workshop to have a spot off boat to work on on 'em.
Ain't that Marine-Tex grand? I love the stuff!!
"Sub" Ed
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Great job Richard! And the docs are fantastic!
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Thanks guys...your help was critical to getting this project behind me.
I inspected the port side ports and it seems that they received the same type of "cut the channel gasket, apply silicone" fix as the starboard side. Plus, the port side ports now look really awful compared to the starboard side ports. The good thing is that a normal person can't see both sides of the boat at the same time...
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Nice job! I posted earlier that I dropped the Portside aft window over the side onto the rocky boatyard below last month- No need to worry if these ports are not robust for offshore... I picked it up undamaged and installed it!
Enjoy the season and have a safe MEMORIAL DAY!
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I've started doing all four of my fixed ports and I'm wondering... The cabin thickness on my boat is 3/8" (.375) at the skinniest, the gap in between the window frame pressure ring (interior ring) and the frame's outer seal is .575". That means that we have to fill .200" with something to keep compression on the gasketing/sealing material (I'm using Butyl tape). So the question is, has anyone considered making a trim ring to fit in between the cabin wall and the pressure ring to close the gap with something solid?
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You can use your calipers to find the largest average thickness of both inside liner and boat's outside cabin sides. Then using matchsticks shim the thinner areas to match. Then use thickened epoxy to bridge gaps and make a solid unibody for the ports to fit into.
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mj:
I may not have understood your proposed solution correctly but if I did, the following thoughts may be useful:
1. On Libations, the combined thickness of the inner cabin liner and the exterior cabin wall was not uniform. The thickness of the the two pieces varied a fair amount and thus, the gap between the two varied too. A trim ring (of uniform thickness) placed inside of the interior liner as I believe you have suggested would seem to do little to provide a solid (no flexing) and surface of uniform thickness for the port frame to be tightened against. In my opinion, it is the flexing of the liner and/or cabin wall that poses the greatest risk to leakage. My approach was very similar to that suggested by Alma although I used longer Doug fir shims set in epoxy followed by Marine-Tex epoxy putty.
2. The second thought that occurs to me is that the the inner bezel of the port frame assembly may not be structurally strong enough to allow the screws to be sufficiently tightened to pull the exterior cabin wall, the interior cabin liner, and the proposed trim ring together tightly enough to avoid the possibility of flexing. My guess is that the bezel will deform long before you can draw the three pieces of cabin/liner/trim together. And once the bezel starts to deform, the holding power of the frame assembly is diminished. When I did the work on Libations I used several good sized clamps to hold there cabin wall, shims, and cabin liner tightly in place while the epoxy cured. Ultimately, on Libations, it was the epoxy that held everything together, not the mechanical force of the frame assembly. The screws holding the interior bezel to the port frame only needed to exert enough force to compress the butyl tape.
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I would agree with all that has been said. I'm already trying to lesson the variations in total thickness with mahogany wood shims (I have a home wood shop, I like to build furniture for a hobby)and thickened epoxy.
The idea of the trim ring is as follows: With the existing frame there is still .200" of gap when the frame is fully tightened, so we are relying on sealant to fill that gap, and .200" is a lot of gap. We are replying on tightening the inner frame to provide clamping pressure so the outside frame is sealed against the deck side wall. The smaller we make the gap the less movement, the less total reliance on a sealant. Remember, when the frame is completely clamped down, with no sealant there is a .200" air gap. If we lessened that gap to say 50 thousandths ( .050") I think that we will see a better long term outcome. Picture it, Inside wall, trim ring, inner frame. Now the inner frame is pushing on the trim ring as we tighten the screws, that has to be a better situation then before, even if there is variations in wall thickness. Besides, you will get a cute little teak halo around the fixed ports... How's that from trying to convince you? Your smiling right? I am...
Did I explain it any better, still have doubts?
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mj,
Thanks for the detailed explanation. I understand your proposed solution much better now. It sounds quite workable to me...but one last question: if the screws are bottoming out before the frame assembly can be completely tightened onto the cabin/shim/liner can you simply replace the existing screws with shorter ones?
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The limiting factor is the actual depth (thickness) of the frame. When I take both sides of the frame (inner and outer) and have them butt up against each other that is where I got the .575" measurement. Regardless of screw length they can get any closer to each other. Hence the reason for filling the gap with something else.
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Good observation! I had not noticed this but it sounds as though it could certainly pose a problem.
In rereading your posts and taking another look at the photos that I have from my project it seems as though the measurement on your boat of 0.375 inch for the cabin thickness (I assume this is the exterior cabin wall combined with the inner liner thickness) is less than on my boat. On my boat the liner was thinner than the cabin wall but the combined thickness was more than 3/8 inch...I am guessing at this point but I think the combined thickness was probably close to 1/2 inch.
It sounds as though you have this pretty well figured out. Good luck with the completion of the project!
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Richard,
If your total hull thickness is at 1/2" or better the existing frame would be perfect for your boat. I will say I'm little surprised that there is that much difference between our boats, but that is what I have.
On a slightly different question... before we get to that I want to make sure that you and all the people who have posted what to expect in reworking these fixed ports has been a God send to me, so thanks for that. I don't want you to get the idea that I'm finding fault with anything as I ask questions or propose different strategies. I'm an old engineer by training and profession, I always see what isn't working or might work better as I move from project to project.
Now the slightly different question... on the ports I removed I noticed that the window glass gasket had slit itself at the 90 degree bends and each side of the gasket had pulled itself up onto either side of the window glass, removing itself from the channel and providing absolutely no seal. This tells me that the window glass gasket shrinks with age. This seems to be confirmed by the filler gasket in the empty channel which had also shrunk on all the window frames. In your explanation of re-gasketing and replacing the glass into the frame channel, I remember you saying that you needed to stretch the gasket around the corners to get it into the channel. I'm not at this point yet, but I'm wondering about the shrinking. I'm wondering if we should actually be compressing the gasket in the corners instead of stretching it. Just wondering out loud.
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mj,
I appreciate the thoroughness of your approach; it is good for all of us who care for these boats.
On the subject of cabin house and liner thickness, I have only one perspective and that is my boat. And I am not experienced in layup or fiberglass construction techniques. But I believe that I have read somewhere that on this vintage of Pearson the hull (and presumably the cabin house) was a traditional hand layup, which I took to mean that the glass layers were per some spec for the weight of glass cloth and the number of layers) while the inner liner was constructed with less control (some type of chopped glass layup that was sprayed into a mold). I may be all wrong about this but if true it might explain the difference in combined cabin/liner thickness from boat to boat.
On the topic of shrinking glass gasket I don't recall how the gaskets on my boat looked when I removed them but I do recall that an earlier repair by a previous owner had trimmed away the outer part of the gasket and resealed it with silicone. BTW, I am pretty sure that on my boat the leak was at the glass gasket and not at the frame to cabin house interface. I also recall that on the Sea Dragon project summary the first attempt at a fix did not work because of too little sealant in the frame channel at the corners. You mentioned that on your boat the channel was empty behind the glass gasket; perhaps this contributed to the shrinking of the gasket (along with age).
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Remember the window assembly is flat. It will not flex to the contour of the cabinsides exterior. That means you will have thicker sealant at the forward and aft ends to make up for a larger gap. Always replace the vinyl window channel within the frames when you rebed the windows. Many times the leak is between the glass and frame within the vinyl gasket. Good Luck!
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This is the first I've heard about different parts of the boat being hand layup vs. chopped mat, but it makes sense that that is what they would be doing. Thank goodness they had the foresight and discipline to hand lay the hull and deck, not every boat builder did.
On my fixed ports I'd estimate that 30% of the leaking came from the frame to deck joint and that was because the inner pressure frame bends up and away at the curves so no clamping. The remaining 70% of leakage came through the window channel. On just one single window I could fill a large bowl (10 to 12 oz) with water from a single downpour.
We will see how it goes, I got a text from the powder coater and the frames will be ready this afternoon. So I'll be re-assembling and installing them this weekend, followed by the new NFM opening ports which arrived yesterday. Can't wait to finally have a dry boat.
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Richard,
One new revaluation; I re-read your reassembly procedure and started by dry fitting one of my windows. On the first one, in one of the corners the window gasket slid all the way down into the channel on both sides of the window. This can only happen when the channel is so wide that no pressure is exerted on the gasket to glass interface. I measured the width of the window channel on all the frames and it varies widely, it should be relative consistent. I will be adjusting the channel internal wall to obtain a consistent channel width for the full length of the frame. This should help reduce the reliance on liquid sealant.
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Last FYIs,
I finished rebuilding all 4 ports today using the Catalina Direct kit and Richard's example. Tip #1: To get the right amount of window gasket I would dry fit around the window glass and once I got to the beginning I would cut it 1/8 to 3/16 longer. When I completed the final assembly the gasket fit was perfect. Doing the first window was a complete mess and took forever, way too much caulk. Some of my frame sets had bleed holes for the excess caulking to exit and some didn't. The first one didn't... which made it the most difficult. By the time I got to the fourth one, I had adjust the caulking to the right amount, and there was very little mess. When I finished the fourth one it looked like I had been doing this procedure for years. Tip #2: I had the frames on two pipe clamps with 2 x 4s at each end to slowly draw the frame together. Sometimes the ends of the frames would not line up when drawn together, so I would use a third pipe clamp and cross clamp on top of the frames so I could move the clamps together. For example if the top frame was too far to the left to meet the bottom of the frame. One end of the cross clamp would go on the left outside of the top frame and the other end of the cross clamp would go on the right outside of the bottom frame. Turning the clamp would draw the two frames together, worked like a champ. Tip #3: 1 Qt of mineral spirits and 3 rolls of paper towels was the right amount for all four ports.
I do have to say, the Catalina Direct gaskets and caulking (Dow 795) makes a real nice finished fixed port. If I didn't do all the work, I'd swear they were new.
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If you just want the vinyl glazing channel it is available from CR Laurence- very reasonable for 100 ft.
I used this glazing channel without sealant and it works with no leaks.
crlaurence.com
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Just finished doing the starboard windows... what a job. Had to space fiberglass and all that stuff. Powder coated the frames, did put sealant in the glazing channel inside and out, never want to do this again. The other side looks like hell and they are going to stay that way for a long time or they start leaking. Thanks for all the helpful stuff and they do look great.