Forward portside fixed port leak

[Banooma]

Hi,
On my new-to-me 2005 H36, I recently discovered a leak from the forward portside fixed port above the lazarette. This originated from overnight condensation and not a deluge, so I feel I need to address this soon. I've not made this kind of repair before, but assume I can unscrew the aluminum frame from the inside, carefully pry off the exterior frame and pane from the outside, clean up the sealant, and then reseal and re-attach. The potential problem I anticipate is that the frame does not perfectly match the curve of the deck. There is no frame to gelcoat gap along most of the port, but a gap of around 2 to 3 mm to the forward end. I've used butyl tape successfully before where there was no visible gap. Hopefully other Hunter owners have dealt with the same. Can I count on butyl tape to work in this case?

 

[RitSim]

I've resealed fixed ports on at least 2 boats. The first mistake that people make is the sealant is squeezed to a very thin layer (tighter is better "rule"). The sealant has a finite elongation usually expressed in percent. So if the sealant has 200% elongation before failure and the sealant thickness is very thin say .020" then the max flex of the sealant is .040". if the sealant thickness is .12" then there is plenty of elongation before failure. 3M makes a double sided tape for this purpose.
General steps:
1) Remove the light and do a thorough cleanup especially if RTV type silicone was previously used.
2) Mark the location of the port light frame and apply blue tape on the light (both inside and outside) and hull {inside and outside) to limit the sealant application
3) Test fit the light. Pencil mark the outline of the light and maybe tape two wood blocks on the low side of the opening for the light final position, this will help placing the light and tape - one try only or start over.
4)Final cleanup of the light frame with acetone or similar.
5) Apply the tape to the hull opening (leave the tape paper on to allow for a final check) if the opening is regular or the light leaving 1/4" from the outside edge and hopefully the tape also is not showing on the interior opening to allow for final sealant.
6)When ready, remove the tape release paper and place the light carefully on the hull - you only get one chance.
7) Use clamps, braces and weights as needed to press against the frame to set the tape. Read the tape instructions as to set time if any.
8) Seal inside and out with glazing sealant such as Dow 795- available locally or from places like McMaster.com. This sealant is made for this purpose. Do not use RTV. This sealant acts differently that RTV and takes a little practice. Tool the sealant so there is no step at the tape edge.
9) When the tape has skinned over, the tape inside and out can be removed.

Good luck

 

[Ralph Johnstone]

This originated from overnight condensation and not a deluge, so I feel I need to address this soon.

Could you please clarify this statement ? If the source of water has been determined to be condensation, then there is no leak.

 

[Banooma]

Fair question. Not interior condensation. The AC was on all night and working fine. I was referring to overnight condensation from fog that settled on the deck, then dripped from deck along the fixed window frame, through old dried sealant, and into the cabin.

 

[Ralph Johnstone]

I see said the blind man. Wrong condensation.

@RitSim 's procedure is what you want.

 

[Banooma]

Thank you. I feel I'm the blind one here. Just to try to be clear, I am referring to aluminum-framed fixed windows above the deck. Part of the instructions refer to the hull. I read elsewhere that butyl tape was good for this type of application- an aluminum frame window against fiberglass/gelcoat. Did I misunderstand? I will clearly also have to do some research to figure out if Hunter used RTV silicone, or how to tell what it is. I assumed the glass is somewhat permanently affixed to the outer frame. Is there any risk to losing that adhesion when pulling the outside component away from the deck? The interior frame appears to be screwed into the exterior frame. Following RitSim's guidance, I will have to look closer to see why I would want to seal inside and out. With the Hunter's interior vinyl liner, I'm not even sure what I would seal from inside. Could you clarify?

 

[Ralph Johnstone]

I will clearly also have to do some research to figure out if Hunter used RTV silicone, or how to tell what it is.

I'm going to stick my neck out by a mile here but, seeing as how Hunter went through tons of Dow Corning 795 back then for unframed, non opening port and hatch lights, I figure they would also use 795 on framed non opening windows as well. It's used as a sealant and appears to have some pretty good adhesive properties as well. I find it's a bitch to get off both FG and acrylic which says good adhesive.

I read elsewhere that butyl tape was good for this type of application- an aluminum frame window against fiberglass/gelcoat. Did I misunderstand?

IMO, butyl tape is a sealant only with no adhesive properties (it never sets). Perfect for parts like bolted on cleats which get all their holding strength from the bolts and rely on the butyl for sealing only. Aluminum frames may want to slide with extremes of temperature change and no real holding strength for lateral movement. There you're going to want a good adhesive which is also a sealant.

Following RitSim's guidance, I will have to look closer to see why I would want to seal inside and out.

You never want to seal inside. It hides any external leaks and the next thing you know :

OOPS

There is no frame to gelcoat gap along most of the port, but a gap of around 2 to 3 mm to the forward end.

Ouch, that's just a bad fit. If it were me, I would complete the job ignoring the gap.

HOWEVER, once the job was completed, I would take a new tube of sealant, cut the tip as small as possible, heat the tip with a heat gun, and squeeze the tip to a fine outlet. I would then run around the exterior of the frame, trying to inject as much sealant as possible.

Is there any way you could load great quantities of sealant into the frame so that it would ooze out as you tightened the screws thereby ensuring a good seal ?

Also, can you share any literature you have on these lights. They are probably Lewmar. I only have experience with the frameless lights back in the day.

 

[RitSim]

My error on mentioning the hull. The comments apply to either the hull ports I have or the deck /cabin ports you have. On my Catalina 30 the aluminum frames were in, if I remember correctly, two parts where the plexi was wrapped with a vinyl extrusion that fit into the aluminum slot. My vinyl was shot and I couldn't find a replacement. I used the Dow 795 for the track and the gap in the aluminum. My port openings in the cabin did not have a balsa or other core so the interior sealing was mostly for finishing. If you have a core then I would not seal the inside. There are several YouTube videos on use of the 3M tape for this application.

 

[DayDreamer41]

@Banooma I am almost certain that the inside aluminum frame is a trim piece only and doesn't have anything to do with the sealing of the port light. I wish I could find the video on sealing these Hunter port lights as there a many which have leaked. I also believe that the outside aluminum frame is also just a trim piece and has to be gently removed in order to even start the plexi removal, I have read where this job must be done very slowly as if you bend the frame you may not be able to find a replacement. If I remember correctly is was done by sliding a sharpened putty knife between the frame and the deck and go around and cut any bond to the deck while slowly prying outward, once that is off the plexi is next and is accomplished by feeding a wire between the deck flange and the plexi and slowly work your way around the plexi cutting the sealant as you go.
I have not done this but I am sure on our 41DS I will have to sooner than later.

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