Resealing the Hull to Deck Joint

DArcy

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Feb 11, 2017
1,690
Islander Freeport 36 Ottawa
I've had this boat for a year now. I knew there were some rain leaks but I didn't know where. The previous owner thought the large saloon windows leaked and he had this crack seal stuff he would apply now and then. I've never seen that stuff work so I started removing and rebedding the windows. They had been rebedded at some point in the past with silicone and they did leak but only a bit. I managed to get the leaks to stop but I think new windows may be in my future. One Islander Freeport 36 owner replaced the plastic framed windows with aluminum and they look great (and they look very expensive as well).
A day after I rebedded the starboard windows it rained and it was dry under the windows but I found a pretty bad leak at the back of a cabinet. Further investigation showed it was the hull to deck joint. :thumbsdown: I discussed this with the IF36 user group (which is very keen and active) and found this is a common problem with these boats. Several people had already resealed the joint and a couple said they needed to do it. The sealant Islander used dried up and just doesn't seal any more. The leak was really bad all along the starboard side; the port side seemed ok. I decided it had to be done so as soon as I hauled out I started taking it apart. The deck hardware on the teak cap rail came off first then I removed the cap rail. The sealant under the cap rail was really dry. The brown flake stuff was, at one point, sealant.
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What I found was more than a little disturbing. The starboard cap rail had been replaced previously, possibly do to a collision although the hull did not have signs of any major repair so it looks like whatever damage there was, was limited to the cap rail. The problem is how the original cap rail was removed. The factory used #14 wood screws to fasten the hull to deck joint but then through bolted the cap rail with 1/4-20 machine screws and nuts through the cap rail, deck and hull which held it all together very securely. The problem is whoever removed the cap rail couldn't figure out how to remove the machine screws so it appears he used a 1" hole saw to just cut the cap rail around the screws then hacksawed through the screws and left the now headless screws in the hull. :banghead: I actually found one of these headless screws in August and could not figure out where it came from. Turns out they were all along the starboard joint.
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The person who worked on this before (trying to be nice here) did a lot of damage with the hole saw that needed to be patched up. Here is one of the holes in the deck he created with the headless screw still in it.
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I got to practice my fiberglass skills. There was one damaged spot on the hull right aft on the starboard side that had been patched with a filler. It was a small area but I ground it out and built it pack up with glass and epoxy. The port side appeared to be all original. The trick was getting inside to reach all the nuts. My daughter was working at a restaurant that was shut down in the second wave of COVID-19 so I hired her to help get this job done. She is a hard worker and was a big help (I also got to hang out with my teenage daughter which doesn't happen often these days :))
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The trick I learned from those that travelled this route before me was to open up the joint with some wedges, up to 3/8" in some places, other places would only open up 1/4" then use a rasp in an oscillating multitool to grind out the sealant. A lot of it just flaked out it was so dry.
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Once it was cleaned out I used 1/8" thick UHMW spacers to maintain the gap for the sealant and shot in as much 5200 as I could. I've never wanted to use 5200 on my boat before but this is a job I don't ever expect to do again - it is now permanent. A couple days later I removed the spacers and filled the gaps with more 5200.
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It's done now, I hope to have a much dryer boat next summer :D
My winter project is to refinish the teak cap rails then reinstall them in the spring.
 
Last edited:
Oct 19, 2017
7,732
O'Day 19 Littleton, NH
Great post and a good looking job. I especially appreciate the part about getting to work with your daughter. I never wanted to work for my father, as a kid. I always worked on other captain's boats, never the Old Man's.

I expect the next owner will never be able to appreciate the problems he/she doesn't inherent because of your work.

-Will (Dragonfly)
 
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
Nice methodical work @DArcy :thumbup:

Should be a fun dry sail come Spring. May Spring come early for you.
 
Mar 12, 2021
3
Islander 36B Fort Walton Beach
How did you get to the bolts from the inside to get the teak rail off, without tearing apart the interior? Also did you re fasten the deck to the haul with the same fasteners? I’m about to do the exact same thing on a new to me 36B islander.
 
Mar 12, 2021
3
Islander 36B Fort Walton Beach
I’ve read the post a handful of times. Darcy said the previous owner used a hole saw but it was only done on the starboard side, the port side was “intact”. He mentioned how he recruited his daughter to get to the bolts from the inside. I’m curious how they did this. Also how he fastened the deck on the starboard side where the previous owner removed the bolts with the home saw.
 
Jul 26, 2009
291
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Kapunui, you may want to PM DArcy in the event he/she doesn't see this thread is active again.
 

DArcy

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Feb 11, 2017
1,690
Islander Freeport 36 Ottawa
@Kapunui Hi Ryan, I got your message but I'll reply here in case someone else is looking for the same answers. First, are you on the foggers group?
This is the definitive place to go for information on Islander Freeport 36s. I posted a bit more detail there in a PDF. I see it wants a log in to access the file so I'll attach it here.
Accessing the nuts to remove the cap rail from inside requires a little contortionism but is doable without removing furniture. I used a combination of standard spanners, socket wrench, extended sockets, vice grips and ratchet box wrench. There are some between the head and berth on the port side that are really challenging to reach. You really need two people for this job, the only ones I was able to remove on my own were in the anchor locker where you can reach through the access ports inside the anchor locker (I assume those ports are standard and weren't added to my boat at some point).
The hull to deck was screwed together using wood screws which are much easier to remove but I replaced them with through bolts and nuts. Getting those nuts on is more challenging than removing them. You figure it out as you go but a little sealant on the wrench helps to hold the nuts in place for the harder to reach ones. It is a very messy job, disposable gloves and cleaning your tools with acetone after is a good idea. Oh, there was one location on the port rail between the head and pullman berth I could not reach so I used a wood screw.
I just did this in the fall and wanted to get the cover on the boat before the snow hit so I have not re-installed the teak cap rails yet, they are still in my garage. I have started removing the old finish from them and will seal them with epoxy before re-installing. I plan on through bolting the cap rail again when I install it.
It was a very daunting task going in but is really just a lot of hours, nothing very challenging. Anyone with basic DIY skills should be able to do the job. I will re-iterate that using a rasp on an oscillating tool is THE way to go for cleaning out the old sealant between the deck and hull. I cannot imagine doing this with manual tools.
 

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Mar 12, 2021
3
Islander 36B Fort Walton Beach
Thank you very much! I’ll be sure to post my experience with process as well!
 
Apr 19, 2021
2
Dufour 2800cs Cap-à-l'aigle
Great read, I do have a few questions as I need to this on my Dufour 2800cs. This is my second season and yes the water is coming from there... I am lucky that the deck to hull bolts are all accessible from the outside (great engineering). I am pretty sure you have removed your mast to do the work, as I don't see it in any pictures, I am pondering doing it without removing the mast, and wondering if this is a big no no. I would also like to know how you prevented the sealant from sticking to the spacers, you also mentioned that you waited a day before removing them and then filled out the gaps, does the deck still crush the sealant joint not causing any issues? I am sure that I will think of more issues before I tackle this with my son before we pout the boat in the water for the season.

Thank you, this was by far the best post I found on the subject.
 

DArcy

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Feb 11, 2017
1,690
Islander Freeport 36 Ottawa
Hi @Sailing Serenity You are very fortunate, it looks like you have an outward turning flange for the hull to deck joint which will make the job much easier and, I'm sure, quicker. The limiting factor on how much you can open the gap is going to be where the bulkheads are bonded to both the hull and the deck. As I mentioned, I could open up about 1/4" to 3/8" (6 ~ 9mm) depending on the location. Your boat may be different.

Yes, removed my mast but it isn't absolutely necessary. Looking at a couple pictures of Dufour 2800 your shrouds should be OK to leave installed but the forestay and backstay may get in the way. On my boat I had to remove the forestay since the chainplate is integrated into the bow roller and it all needed to come off to remove the cap rail and to access the hull to deck joint. I have seen pictures of another Islander Freeport 36 which did this job in the water with the mast up. They just ran a halyard to a point (I think it was a bow cleat) on the deck to support the mast. A deck stepped mast might be a bit more challenging to support but should still be doable.

I used 1/8" (3mm) thick UHMW (polyethylene) for the spacers. As you can see in the pictures I left a bit hanging out that I could grab with pliers and pull out and they all came out fairly easily. The 5200 doesn't stick all that well to UHMW and it was not fully cured after a couple days. After setting up for a couple of days the sealant is fairly hard so doesn't flow when removing the spacers. After pulling them out there was a 1/8" x 3/4" gap which I filled with more sealant. I squeezed the applicator tip of the sealant tube into the gap and filled from the back to the front. You can build a bit of pressure to ensure the gap is filled, just make sure to cover anything from squeeze out on the inside. I am fairly confident that as long as there are no voids the joint is well sealed. I just finished the job last fall and still have the cover on so I haven't tested the seal yet.

Good luck and let us know how it goes.
 
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Likes: Will Gilmore
Apr 19, 2021
2
Dufour 2800cs Cap-à-l'aigle
Thank you @DArcy ,

I really appreciate you taking the time to share all these details, This is my first boat and the previous owner omitted to give it the love she deserves. Every task is me learning something new and this one will raise the bar, thanks to people like you, It is possible for budget sailors like myself to live the dream. I will definitely let you know how it goes as soon as I can get a W/E of good weather to start the project.

So far I have remade the cooling system of a 42 year old MD7A cooling system (3 mechanics said to buy a new engine she purrs like a 40 year old kitten now...) , resealed the deck hatches, revamped all the exterior teak and currently changing out the whole sceptic system as the previous owner thought that the water bag was the sceptic tank and left the real tank full for five Canadian winters (the stink was atrocious)... Still have plenty of projects to accomplish but the point is, every project I take on is possible due to sailors like yourself sharing your knowledge and experiences. I was even able to squeeze half a season of sailing in last year and looking forward to a full one this year.

Have a great day,
 

hl1234

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Mar 20, 2023
1
Beneteau 423 Marion MA
@DArcy,
I am looking at the same problem and project for a Beneteau. With the additional 1/8” from the spacers have you, or do you anticipate needing to hollow out the underside of the caprail?

Thanks,
Harry
 

DArcy

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Feb 11, 2017
1,690
Islander Freeport 36 Ottawa
The spacers are only used to provide sufficient gap to squeeze in the 5200 sealant. I removed the spacers after 24 hours, squeezed in some more 5200 where the spacers were, then torqued down the screws (backing nuts actually to avoid disturbing the sealant around the screws). The spacing was about the same as original by the time I was done. And the cap rail on my boat just sits on top of the hull to deck joint so any small difference would not matter.
 

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