Portlight Replacement -- Gap between Cabin top and liner

[jstark]

Hi Maine Sail,

I'm working on following your guide for replacing portlights. I have a '75 Ericson 35-2 and I'm replacing the smaller portlights with the New Found Metals 14x4s. When removing the factory pieces I found that the cabin top wasn't a sold piece of fiberglass as seen in your pictures and the videos from New Found Metals. Instead its an outside layer and an inside layer, with a varying air gap, and on some holes a strip of epoxy between the lower layers.

My question is, how should I go about filling this in? I've read on the Beckson site that they recommend foam or plywood for their installs, but wanted to get your opinion.

Thanks!

 

[walmsleyc]

I did the same basic job on my 87 Hunter Legend 35. The cabintop/deck was a cored (plywood), with an inner liner, and an air gap of varying size between the two. I am quite convinced that the independent flex and motion between the liner and the cabin cause the sealant/seals around the port lights to fail, resulting is leaking, and rotten core. Hunter or a PO had tried to screw the liner to the cabin with short screws. Virtually ALL of those screw were too short to do much, and really only bit into the inner layer of glass on the cabin laminate.

Aside from lots of effort in removing rotten core, and filling and repairing that, I decided to do two things to make the job last longer. I bonded the liner and the cabin together around each of the windows through the use of clamps, jigs and thickened epoxy.

Then, when installing the new port lights (Beckson), I used their barrel bolt option so that the port light was bolted through ALL layers of material. The flush barrel bolt "nut" is on the outside, and flush with the gelcoat and gets covered with the trim ring.

The result is a port light and opening that will not shift and flex when the boat is under sail (at least not independently of all the different layers), and where there is no longer ANY exposed core in case it does leak. Replacing a port light is 10x more of a pain if you also have to deal with rotten core that extends 2-5 inches in.

I ended up using the empty/blank West System empty epoxy tubes, filled with thickened epoxy in order to inject enough epoxy between the liner and cabin top. Be careful ... filling large voids with epoxy can generate lots of heat. The tubes can be used over and over again. I also built thick plywood (3/4") clamping rings for the inside and outside so that once the epoxy was applied, I could clamp it up, and would get a relatively flat surface (clamps alone would have resulted in a wavy surface because the liner is pretty thin).

Any variability in overall thickness didn't matter for me, because once fitted, I marked the new port lights on the outside, and trimmed them flush to the trim ring on the outside. Helps them drain better, and less things to knock your ankle on.

Chris

 

[njsail]

The outer fiberglass wall is most likely thick enough to not flex much. The inner wall you need to determine how much flex it has. I did 9 of the New Found Metals on an Island Packet many years ago and I didn't fill the gap. The NFM portlights have through bolts and connect from the inside to the outer ring. The outer ring is solid and once you bed it with Butyl it's not going anywhere. Just make sure to snug it down good (not over tight). If you find there is flex on the first one installation you can use a couple strips of wood and just glue them between the walls. I unfortunately had to cur fiberglass to get the ports to fit properly but that's a different story. Use Gray butyl vs black. I didn't know the difference at the time. After you install the ports don't forget to put a ring of urethane to isolate the butyl. NFM has good instructions on their site.

Here's a photo set of the NFM installation I did. It was worth the effort. Good luck!
http://ipphotos.com/view_ad.asp?Ad_ID=117

 

[jstark]

Both sides seem pretty flexible. I'm able to grab and squeeze them together with very little effort. I was thinking that I will need something solid between them for two reasons:

1 When I pack the butyl in around the inside port piece (from the outside) if there is nothing between the two pieces, won't the butyl just keep expanding out into the gap?

2 I measured the thickness of the cabin top for the screw lengths with my calipers and I have ranges like .30 min to .56 max on a single port. They all vary with the largest being .46 min to .70 max.

I was thinking that putting in epoxy soaked marine ply in a "ring" around the cutout would give me more uniformity and something for the butyl to press against. I'm afraid to use thickened epoxy because I then still have the problem of the varying gap.

Is there anything that I'm not taking into account that would make this a bad idea?

 

[Harlan]

Replaced portlights on my OD34 - same situation. I filled in the gap with thickened epoxy - West with slow hardener and cabosil. This is too big a gap and too much epoxy to use the fast hardener - goes off too fast, gets too hot. I used Lewmar portlights and just used various length screws to accomodate any change in wall thickness from one end of the portlight to the other. I would not try to clamp the liner to the deck - just fill the gap. Filling the gap means you can tighten the screws appropriately for a good seal and if any leaks do happen to develop over the years the water will leak into the cabin and signal that a fix is needed - rather than dripping between the deck and liner causing unknown damage. I made a template and then used a router to clean up the epoxy edge and make a nice finished cutout.

 

[coxwaine1]

I just completed the same project on my H34 with NFM 5x12s. I too had the same gap and I found Evercoat Sealant and Spray Foam. I masked the port with tape and let the foam fill in the gaps. I certainly worked well and since it is a closed cell foam it says it is waterproof so need to worry about it accumulating moisture. I had tried the thickened epoxy route for the bottom, but I had a gap at the top and the foam expanded to fill all gaps. When it cured I just sanded it flush. Good luck and have fun!

 

[njsail]

I like coxwaine1's idea of using foam. I hadn't thought of that. The NFM stainless ports are not going to flex at all. They are built to very tight tolerance and when you add all the screws from the inside and tighten them down you get a very snug fit. You can't put the butyl too thick on the outside or you'll end up having trouble compressing it down to where it will be properly fitted against the outside wall. I did this a couple times before I got the hang of it. I had 4 Quick clamps that I could put 2 on top and 2 on bottom of port and pump them until it was properly in place. I made a slight bevel on the outer edge of the hole so the butyl would have a little room to set. Check out the video. If I did it again I would have used the foam trick. That stuff hardens like rock. I don't know why I didn't think of that. +1 for the guy who did.

here is the link to the youtube NFM installation instruction video's.
http://www.youtube.com/user/newfoundmetals

 

[sailingseadragon]

Jstark,

I wrestled with the same question before replacing the Beckson ports that came with our Pearson... Below is a link to how I filled the gap.

http://www.sailingseadragon.com/Ports.htm


Garner

 

[jstark]

Garner,
This is just what I had in mind, now I think I just need to figure out what a happy median would be for the thickness and order some fiberglass.

 

[njsail]

Garner - awesome job on the instructional photo set.

Jstark,

I wrestled with the same question before replacing the Beckson ports that came with our Pearson... Below is a link to how I filled the gap.

http://www.sailingseadragon.com/Ports.htm


Garner