Leaking Portlight / Porthole

[dbsea]

Hi All,

I'm new to my 2016 C-30CB as of yesterday, and very excited but as with any boat, there are a few minor issues. This one seems like it's at the top of my list, and looking for guidance on how to deal with it. Firstly, it appears that the starboard aft portlight/porthole is leaking into the quarter berth, and it's dripping down the monkey fur and has caused some discoloration / staining on the monkey fur and the teak shelf that's below it. The pictures don't adequately show the teak damage, it seems worse than it was in the photos attached.

1) how do I fix these portholes/portlights and not have it look like they currently do? looks like the sealant use was a little "aggressive"...

2) how do I dry out the monkey fur?

3) how do I deal with the teak discoloration / damage?

Photos: https://www.icloud.com/sharedalbum/#B0hG6XBubsGED9

Thanks!

 

[FlyMeAway]

Oof. That looks like a very poorly done "repair" job.

I have not replaced one of the portlights on my tug but I've done similar repairs on other boats. Here is what I would suggest, though these recommendations assume that the portlights on our boat are standard, thru-bolted portlights and not screwed into hardware embedded in the fiberglass:

Start by removing the portlight. Depending on what exactly what used (I can't tell if it is just caulk/silcone or adhesive caulk) it may be some work to completely clean the area and remove all the old gunk.

Then, you want to re-bed the portlights with an adhesive sealant. IMHO you only need to apply to the exterior. You should be able to find videos/instructions online for bedding portlights with adhesive sealant.

Personally, 3M 4200 is the only thing I would use to re-bed these (pick your color; I might use black). Other manufacturers (Sikaflex) claim to have comparable products but I think of 3M as the gold standard. Some might suggest using butyl tape and not adhesive, but don't think that's ideal for this application -- and caulk/silicone is generally a bad idea regardless (DM me and I can discuss at length). Butyl tape would work only if the portlights are screwed into hardware that is embedded in the hull with a metal backing plate (which I am somewhat but not totally certain is not the case here). Do not -- I repeat, do not -- use 3M 5200. I also don't think you need 4200FC (the fast-cure version) as it is a little harder to work with and I would only use it in applications where you don't have screws/bolts holding things together.

But one thing to remember is that the screws are not really there to affix the portlight; they are only there to hold things in place while the adhesive dries. As one of my Mechanical Engineering professors liked to say, airplanes aren't really held together by rivets, they are held together by glue -- the rivets are only there to hold things in place while the glue dries.

 

[dbsea]

Thank you. I'm wondering if the actual portlight itself needs replacement - they are 6 years old. If that's the case, I might reach out to Fluid Motion to see if it's a standard size and I can replace it with a higher quality hatch...

 

[FlyMeAway]

Thank you. I'm wondering if the actual portlight itself needs replacement - they are 6 years old. If that's the case, I might reach out to Fluid Motion to see if it's a standard size and I can replace it with a higher quality hatch...

IME I would be surprised if this is the case. You can start by removing it to find out -- closely inspect for cracks, etc.

Also, where is the leak coming through? I read your earlier post as the portlight leaking through the exterior seal not the interior gasket. If the internal gasket seal, those can be replaced independently of replacing the entire portlight. Might be easier to do if you remove it, but also a straightforward repair.

 

[dbsea]

Thank you. I'm wondering if the actual portlight itself needs replacement - they are 6 years old. If that's the case, I might reach out to Fluid Motion to see if it's a standard size and I can replace it with a higher quality hatch...

IME I would be surprised if this is the case. You can start by removing it to find out -- closely inspect for cracks, etc.

Also, where is the leak coming through? I read your earlier post as the portlight leaking through the exterior seal not the interior gasket. If the internal gasket seal, those can be replaced independently of replacing the entire portlight. Might be easier to do if you remove it, but also a straightforward repair.

TBH not sure where the leak is originating yet. Will need to investigate...

 

[Ralf H]

Hi dbsea,

The portlights themselves should still be ok. They would take a lot longer to "wear out" or get damaged from use, UV rays, etc. As others have mentioned, check to make sure the inner seal is not leaking and if it is indeed through the outer seal, then remove the portlights, remove all of the sealant and create a clean surface for the new sealant, then reapply a silicone sealant. We use Sikaflex 291, but if that is not readily at hand, 3M 4200 will do very well. Hope this helps.

Cheers,

Ralf

 

[FlyMeAway]

Apparently 3M has discontinued the "regular" cure 4200 (fast cure is the only one still available). BUT, 3M recommends 4000UV for portlights. Here's their brochure:

https://multimedia.3m.com/mws/media/151 ... owners.pdf

I do think that the 3M vs. Sikaflex debate is one of those things that will never be settled. I've found that 3M products are easier to work with for the DIYer, but that's a personal preference. Practical Sailor seemed to like them both equally: https://www.practical-sailor.com/boat-m ... d-sealants

One thing to remember about either: you have to be *really* careful to keep them away from the plastic of the portlight lens (I think it's plastic, not glass?). It's polyurethane and bad things will happen if you let them touch. I can't believe it took the PS article to remind me of that, as I've had a bad experience in the past 🙂

 

[bob daily]

After looking at your photos of your port holes, I noticed that the screws are not what the factory uses! They are philips not square, and not properly installed. The prior fix was poorly dune and something I would expect on a 14 ft John boat, not a $200.000 cutwater! I would be very worried of prior maintenance of this vessel if this is any indication of how it was maintained. Bob

 

[keepondancin]

Just a lurker here. Take a look at this website, has info on rebedding port lights. I replaced 8 in my boat using this as a guideline.https://marinehowto.com/installing-newf ... ortlights/. Take a look at other articles, very informative.

 

[FlyMeAway]

Just a lurker here. Take a look at this website, has info on rebedding port lights. I replaced 8 in my boat using this as a guideline.https://marinehowto.com/installing-newf ... ortlights/. Take a look at other articles, very informative.

That's MaineSail; he's literally a legend in the sailing community. You will learn a *lot* from his website that is applicable to our boats as well.

FWIW, Compass Marine (his company) invented Bed-It tape (marine-grade butyl tape) and so they are very partial to it. I personally wouldn't use butyl tape unless both sides of the fixture are metal (vs. one or both sides being plastic/polycarb), but that's because I once cracked a plastic fixture before the butyl tape was satisfactorily compressed. YMMV.

 

[dbsea]

After looking at your photos of your port holes, I noticed that the screws are not what the factory uses! They are philips not square, and not properly installed. The prior fix was poorly dune and something I would expect on a 14 ft John boat, not a $200.000 cutwater! I would be very worried of prior maintenance of this vessel if this is any indication of how it was maintained. Bob

Hi Bob- I spoke to the former owner and he assured me he couldn’t figure out how to remove them, hence the sealant around the outside edges. are we 100% sure cutwater never uses Philips? I don’t want to be unnecessarily spooked. I had a full survey done by a reputable surveyor and the boat was found to be in well above average condition…

 

[dbsea]

Hi dbsea,

The portlights themselves should still be ok. They would take a lot longer to "wear out" or get damaged from use, UV rays, etc. As others have mentioned, check to make sure the inner seal is not leaking and if it is indeed through the outer seal, then remove the portlights, remove all of the sealant and create a clean surface for the new sealant, then reapply a silicone sealant. We use Sikaflex 291, but if that is not readily at hand, 3M 4200 will do very well. Hope this helps.

Cheers,

Ralf

Hi Ralf, how do I better understand if it’s the inner or outer seal?

 

[Ralf H]

Hi dbsea,

What I call the inner seal would be the rubber seal in the window that you can close. The outer seal is the sealant (Sikaflex in this case) we applied when we installed the windows. Hope that helps clear it up a bit.

Cheers!

Ralf