Hull to Deck Joint Repair and Filler

G

GearWhore

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Jun 22, 2010
11
Hunter 240 Deer Creek
I have a 2000 Hunter 240 that has developed a leak at the stern. There was just a trickle of water coming through pin holes in the glassed-over interior deck to hull joint while sailing last summer. I could see minor cracking in the new hull paint at that joint, but no obvious intrusion point. I tipped the trailer back on some blocks and filled the back of the bilge with water from a hose. There were a couple small seeps at first, then the whole joint seemed to go with water seeping along most of it after a minute or two. Not surprised it failed, but surprised it held up as long as it has.

I removed the hull paint and it appears to have a marine bondo type filler between the two hull pieces, with an approximate 1.25" gap at the lip. A lot of voids in the filler material as I started pulling out chipped pieces. Several cracks in the filler were also darker indicating water passing through them.

Now my question has to do with repairing the joint. I will clean the filler out of the old joint, then thinking I can probably inject 5200 along the actual seam up inside the joint cavity (I don't want to force it apart if I don't have to as it will further damage the fiberglass over the joint on the inside). That will get me water tight. Then I'm not sure what material I'd use to fill the rest of the 1"x1.25" cavity. I think I need something that stays somewhat flexible?

Last year I split the hull joint under the rub rail on the port side minimally from stern to chainplates and filled the joint with 3M 5200 to fix another leak.

Thoughts, ideas, suggestions, and admonitions are all appreciated.
 

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rgranger

rgranger

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Jan 19, 2010
12,542
Hobie 16 & Rhodes 22 Skeeter Charleston
Wow. That does not look right. Almost like a part of your boat is missing. I’m sure someone will baulk at this suggestion but... what if you partially filled it in with fireblock closed cell foam leaving about 1/16th of an inch and scribed and jigged a plastic “lip” that inserted like a lid. You would need to router the lip so it would insert and then 4200 it along the edge of the insert that touches the inner wall if the deck joint.

Reading this I’m not sure if that is clear but I can see it in my mind. If you want, I can try and make a diagram.

46C113DD-CE6C-4EA6-ADD5-5421CE0A7E01.jpeg
 
G

GearWhore

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Jun 22, 2010
11
Hunter 240 Deer Creek
I get where you're going with the suggestion. My first thought was the closed cell expanding foam. Not sure I would need to add a cap either, just shave to match the edges and recover with bottom paint.

My two concerns are the temp swings the hull goes through and the flexibility of the material after it sets.

There doesn't appear to be anything missing, just a weird detail in the stern joint...
 
rgranger

rgranger

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Jan 19, 2010
12,542
Hobie 16 & Rhodes 22 Skeeter Charleston
Tough spot. If it works ... great! Easy fix. If it don’t ... getting that foam out is not an easy job.

Maybe test the idea out on a small spot before you go all in
 
D

dlochner

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Jan 11, 2014
12,117
Sabre 362 113 Fair Haven, NY
Have you looked at other Hunter 240s to see how the factory dealt with this?

When decks are attached to hulls a lot of thickened resin is often used to bond the two pieces together in addition the hull deck joint. This provides some support for the hull and liner. I would be hesitant about removing any of the existing filler.
 
G

GearWhore

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Jun 22, 2010
11
Hunter 240 Deer Creek
I have only ever seen a listing of one other Hunter 240 in Utah so there aren't too many of us around. There is a 260 I've seen on a trailer twice in 10 years. Good suggestion though.

I don't believe this is thickened resin. The color is wrong and the texture is powdery as it is scraped or broken away (along with some little fibers I can see).

I was hesitant about removing the filler but some of the cracked pieces were a little loose. When I chipped them out and noticed the unintentional voids/cavities behind I knew it all had to come out. The filler was cracked though and the dark staining on the cracks and backside indicate water sits and passes through the voids. The actual contact joint between the upper and lower hulls is up in the back end of the cavity, maybe 1-2" from the edge, then the pieces flare out to this form.

I'm hopeful a couple rounds of 5200 at the joint will fix the leak. Then I'm just not sure what is the appropriate material to fill the rest of the void...
 
D

dlochner

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Jan 11, 2014
12,117
Sabre 362 113 Fair Haven, NY
The pink color and the way it cracked is very typical of thickened polyester resin, perhaps Bondo. Milled fibers, short pieces of fiberglass threads, are often used to thicken resins. Polyester resin is often pinkish. It is not epoxy, as epoxy is too expensive to use in this application for a boat builder and it takes too long to cure.

The easiest repair might be to clean up the cavity remove all the loose stuff and rough up the surfaces. The fill the void with thickened resin. Because it is a deep void, it should be filled in layers to limit heat build up. If the resin gets too hot it will go "exothermic" and will form gases with which will make the resin turn powdery and foamy.

I really don't see this as an application for 5200 as 5200 is more of an adhesive than a caulk or sealant.
 
rgranger

rgranger

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Jan 19, 2010
12,542
Hobie 16 & Rhodes 22 Skeeter Charleston
dlochner said:
I really don't see this as an application for 5200 as 5200 is more of an adhesive than a caulk or sealant.
Click to expand
:plus:

... and 5200 is a one and done option. You can't undo 5200 without a lot of work. If you really want an adhesive go with 4200. @dlochner 's idea to fill it with resin is a good option but the problem I see is that you would have to turn the boat upside down to do it. If that is something you can do, then I'd second dlochner's idea. If you cannot turn the boat over, then I'm doubling back to the fireblock foam idea.
 
D

dlochner

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Jan 11, 2014
12,117
Sabre 362 113 Fair Haven, NY
rgranger said:
:plus:

... and 5200 is a one and done option. You can't undo 5200 without a lot of work. If you really want an adhesive go with 4200. @dlochner 's idea to fill it with resin is a good option but the problem I see is that you would have to turn the boat upside down to do it. If that is something you can do, then I'd second dlochner's idea. If you cannot turn the boat over, then I'm doubling back to the fireblock foam idea.
Click to expand
Thickened epoxy can be applied to with minimal drip. Make it a peanut butter consistency and put it up in thinner layers, maybe ½" then wait several hours, add another ½" and so forth. Adding subsequent layers before the epoxy is fully cured avoids the amine blush issue and ensures better bonding. Waiting until it is partially cured also reduces the heat build up.
 
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Likes: rgranger
G

GearWhore

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Jun 22, 2010
11
Hunter 240 Deer Creek
Yeah, I have no way to roll the boat. At least not "safely." ;-) The cavity points directly down which has been a concern of mine with epoxy. I'm also concerned that I wouldn't be able to get many of the air pockets pushed out with some of the funky shapes.

Would you recommend adding fiberglass with each or some layers of epoxy?

I called around to some of the fiberglass and boat repair shops in Utah and they are all months out to even take a look.
 
rgranger

rgranger

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Jan 19, 2010
12,542
Hobie 16 & Rhodes 22 Skeeter Charleston
You might want to read some of the articles on this page also

Epoxy Moussant - Sicomin

Avec plus de 20 ans d’expérience dans les systèmes époxy moussant Sicomin a la gamme la plus étendue de densités de mousse époxy performant.
sicomin.com sicomin.com
 
D

dlochner

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Jan 11, 2014
12,117
Sabre 362 113 Fair Haven, NY
If you add the right filler and mix it thick enough, there will be little or no problem working upside down. You will drop some, but not that much.

Here are 2 good references:



The photo is of a strut replacement I did a few years ago. This is after it was cured, but before I faired it. Notice there are no drips. Some of the epoxy fell off the putty knife while I putting it in, but none fell off once on the boat.

DSC_0116.jpeg
 
G

GearWhore

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Jun 22, 2010
11
Hunter 240 Deer Creek
I have been through the West System repair and maintenance manual you linked. I understand all of the concepts and have done some of the fiberglass repairs and reinforcements before on this boat and my old wood E and C scows. However, the size of the gap here is what has me questioning myself and materials, and that it is the only portion of the hull-deck joint that is below water line. I knew I couldn't just fill it with epoxy and walk away.

Looking for an expanding closed cell marine foam I did come across the Evercoat Sprayfoam 100654 (blue can, not the black can stuff)

And their White Marine Filler 100574

Also, BIG thank you to both of you for your ideas, suggestions, links, info, and all else. I start talking about this stuff and my wife's eyes glaze over with "I don't care how, just fix it."
 
D

dlochner

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Jan 11, 2014
12,117
Sabre 362 113 Fair Haven, NY
GearWhore said:
I knew I couldn't just fill it with epoxy and walk away.
Click to expand
Actually, if you do a decent job filling it, you could. Don't make this harder than it already is. Clean it up, fill it with thickened epoxy, building in layers, and fair it to the hull. If you have some barrier coat, put that on or use the barrier coat filler West has. Bottom paint. You're done.

Epoxy is highly water resistant, barrier coats, like Interprotect 2000 are epoxies with a filler.
 
D

dlochner

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Jan 11, 2014
12,117
Sabre 362 113 Fair Haven, NY
GearWhore said:
I meant fill it in one "pour," due to the heat.
Click to expand
OK.

BTW, I too am familiar with the spousal glazed eyes when talking about boat projects. Her standard questions: How long will take? Really? She's learned to not ask the How much will cost question.
 
rgranger

rgranger

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Jan 19, 2010
12,542
Hobie 16 & Rhodes 22 Skeeter Charleston
If you go with an expanding option, you might want to fill a small section at a time. If you cover an area with a smooth film like the acetate sheets your professors used to use....

1618519523737.png


... and trace and cut it so you can tape it over the opening with masking tape... then squirt the expanding spray into the gap behind the film,... the acetate will create a smooth finish and reduce the amount of work you have to do cutting and shaping the foam once it hardens. It has been my experience that the acetate film does not stick to much. It certainly does not stick to epoxy .... so this might also be a helpful trick if you go with dlochner's approach.
 
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