Hull to Deck Joint Repair

[jarod]

Hi All,

I have a fiberglass motorsailer only two were built so unfortunately i don't have a large info base on which to draw ideas and was hoping some of you could help. The hull to deck joint is leaking quite badly. It seems after some rip and tear that the joint is composed of the deck and the hull which come up vertically together to form a hollow bulwark. This hollow was spanned by some fiberglass encased ply which over the years has deteriorated from water ingress. The two fiberglass lips were sandwiched between two teak strips and the entire mess was through bolted. This has led to many opportunites for water to migrate into the hollow bulwark and make its way into the bilge on the boat and who knows where else. I am thinking i will cap the entire thing.... teak, bolts and all with glass/resin then put on a new teak cap rail which will only penetrate the teak pieces to the side of the hollow bulwark. I have a great picture that shows this mess. In any case i hope someone has some specific instructions.

I have included a link to the photo as well. Please just click on the link to Flickr to view and note that the photo is labeled.

IMG-20120825-00423 | Flickr - Photo Sharing!

[micah719]

Aghh! What a mess!

Wouldn't it be safer to clear out all the rotten stuff and see what kind of solution would fit the sound remains of your bulwark? Safer for you, and easier to sell later.

[jarod]

The plan is to remove the entire stainless handrail, then the old teak cap rail, then all of the rotten plywood. The teak on either side of the joint is still very solid good wood so i was planning on simply glassing over the joint and over the teak then placing a new teak cap rail over the glassed in joint. Does this seem like a reasonable course of action?

[Benz]

Glassing over Teak is chancy, since it's oily and doesn't like glues and such. I would dig out all the nasty plywood, fill that space with pour foam until about 1/2" from the top edge of the bulwark, then fill that with fiberglass or G-10 well epoxied-in. If you must put teak over it all, you can tap threads into the G-10, being careful not to pierce through, and bolt the teak straight own onto it. Using an extra-thick layer of G-10 would help you not pierce through, which would then let water in.
pour foam is a messy job, but what boatbuilding project isn't?
Good luck.
Ben

[micah719]

When you reattach the handrail, are you taking precautions that the screwholes don't leak into the void?

Was the ply fulfilling any structural function?

Is the deck attached to the hull anywhere else?

What is likely to be under the anchor roller/fairleads?

What is the join between transom/deck like (assuming there is a transom)?

[jarod]

Thanks for the replies...here are some answers to questions

- I will definately take care not to pierce back into the hollow void with the handrails fasteners
- I don't believe the ply was fulfilling any structural purpose. I think its function was to provide an attachment point for the teak cap rail. I should re-state that the ply was coated with a thin layer of glass.
- I am not sure what was meant by "Was the deck attached to the hull anywhere else?". ...I believe it was attached along the entire perimeter of the boat by the through bolts that went through the teak and fiberglass.
- I have no idea what will be under the anchor roller or the fairleads at this point; however, this question has crossed my mind.
- With respect to the transom and the deck I can only assume it is the same method of attachment that was used in the area that i dismantled although I won't know for sure until i tear that apart.

I am in the PNW so the rainy season is fast approaching so not the time to be tackling this job out of doors. I don't want to do anymore exploratory surgery until the spring when i can count on some drier weather hopefully although in Washington State that is never a guarantee.

Thanks for the ideas and keep them coming please

[micah719]

All the best with your surgery!

[minaret]

Sure this is a doable job. You need to tie the glass in to existing glass on both sides of the repair though. I would remove the cap rail and then back grind about 3"-4" inches onto the inside of the bulwark. It looks like there's a fiberglass lip on the outboard edge that you could grind the inside of and glass on to, it's the only thing not labeled in your photo. A couple more pics might help, with a little more zoom and size. I wouldn't fill the gap with expanding foam, it may expand into your headliner or somewhere else you don't want it to. Just fill the gap with fiberfiller after grinding and then glass over. Normally I'd suggest replacing the ply with Coosa, but it doesn't hold a fastener well enough for this application. G-10 would be nice but very pricy in the amount needed. The affordable option would be too replace it with new ply and just make sure the new caprail is well bedded and well maintained. Make sure that you glass whatever you replace it with in well, it will be holding your caprail and stanchions on and may be subject to large loads. If you just bond in a strip of material and don't glass it in place you are relying on that bond for a lot of strength. Of course if you do go glass to glass that will mean you will need to paint or gelcoat the inside of your bulwarks after glassing and fairing. Give me a shout if you need help acquiring the appropriate materials in Seattle. Where does the boat live? What kind of boat is it?

[micah719]

Perhaps drill out the holes in the new bulwark for the new fasteners and fill with epoxy, then re-drill and use self-tappers. Was the strongest method for screws, I read somewhere. No more leaking then. Maybe a chance to test out methods on that little area, over winter? All the best...

[jarod]

Thanks for the replies

Minaret in response to your reply:

That white piece you see on the outboard side is unfortunately just a piece of decorative wooden trim on the outboard side of the hull and not glass. I should have ripped it off to avoid confusion but i do need to button this mess back together for the winter so just left it. The only glass is what I have labeled. The teak on either side of the glass is sitting on a lip that was moulded into the glass on either side presumably so the teak would sit flush with the hull. Think of it as a moulded in step on both the deck side and the outboard side.

Note the teak is about an inch thick on either side of the join and the fiberglass is about 3/8 on the outboard side and about 1/4 inch on the deck side.

If i go glass to glass bond in this situation I have two choices. One would be to remove the teak on either side of the join which would involve removing many many through bolts and may leave the joint unsecured for a time which could lead to bigger issues. The boat will be on the hard on stands and the forces exerted on the join would be extreme I would think. I would be nervous about unbolting the join in this situation. The second option would be to carry the glass cloth down below the teak on either side of the join. This would be an attractive idea if it weren't for the fact the resulting repair would be ugly to say the least and I would have to either cover it with something which would again involve fastening something to the hull and opening it up to water intrusion again. I have little experience in glass work and I can only imagine it takes great skill to blend the cloth into the gelcoat to make a decent looking repair.

I keep the boat up in Semiahmoo near Blaine and any help you can provide for suppliers in Seattle would be greatly appreciated.


Thanks Jarod

[minaret]

OK, now I see it. You are absolutely right in your summation of the problem. Removing the teak strips and through bolts would be way too much work for the problem at hand, and glassing over them would be wrong on many levels. I would consider that the ply as you said was not structural, and the cap rail was actually fastened to the teak "stringers", not the ply. In that case I would consider filling the gap with fiberfiller and then bonding on Coosa Board to replace the ply. When you fasten the cap rail you can fasten it to the teak "stringers" right through the Coosa, as it was probably done originally. The difference being the Coosa will never rot. Much cheaper than G-10 but plenty strong for this application, especially if you go with a higher density product.

[jarod]

Minaret,

Could I not just fill with the joint fiberfiller as suggested then apply the teak cap rail directly over the filled joint using 5200 or similar to bed down the cap rail and secure it with screws or through bolts through the teak stringers on either side and leave the coos board out of the equation entirely? I could use some thicker teak for the cap rail so that the stainless hand rails had something reasonable to secure to. The end result would be a bulwark of roughly the same height not that i really care if the bulwark comes down an inch or two. Other than the $1500-$2000 in teak this sounds pretty good.

- Should i apply at least a 3 inch wide piece of biaxial cloth to the top surface above the fiber filler?
- Does this fiber filler have any flexibility or will it crack when the hull and deck have movement?
- Also is the fiber filler thick and sticky enough that it will not fall down into that hollow in the bulwark? I suppose i could make a trough out of some sort of tape to hold the filler until it sets up in the top of the hollow.

Jarod

[minaret]

Originally Posted by jarod

Minaret,

Could I not just fill with the joint fiberfiller as suggested then apply the teak cap rail directly over the filled joint using 5200 or similar to bed down the cap rail and secure it with screws or through bolts through the teak stringers on either side and leave the coos board out of the equation entirely? I could use some thicker teak for the cap rail so that the stainless hand rails had something reasonable to secure to. The end result would be a bulwark of roughly the same height not that i really care if the bulwark comes down an inch or two. Other than the $1500-$2000 in teak this sounds pretty good.

Yes, you could do that, though it looks like it would mean cutting down or changing the exterior trim piece we mentioned earlier. It might even look nicer with a beefier cap rail, though it would certainly cost a lot more if you tried to reproduce the original height that way. Make sure there's not some unforseen reason why the rail needs to be at that height before doing this. Either way you are ultimately fastening to the original teak stringers which the through bolts go through. My concern here would be that once you remove all the cap rail and rotten ply, you may find that some areas of those are rotten too. I hope not, because that would be a pain. Perhaps find a way to keep it relatively dry this winter so it doesn't have one more long wet season before you pull it?

- Should i apply at least a 3 inch wide piece of biaxial cloth to the top surface above the fiber filler?

It wouldn't hurt, although the amount of glass you'd be tying into on either side is so small that it wouldn't help much either.


- Does this fiber filler have any flexibility or will it crack when the hull and deck have movement?

It has a little flexibilty, but not much. It will crack if heavily deformed. However, in theory this gap you are filling should flex very little, unless the through bolts in question are loose, which seems highly unlikely. Glassing over as you suggested would help it to not crack.


- Also is the fiber filler thick and sticky enough that it will not fall down into that hollow in the bulwark? I suppose i could make a trough out of some sort of tape to hold the filler until it sets up in the top of the hollow.

It's the perfect consistency for that job. And you can get a 5 gallon bucket of it for cheap, it's easy to work with and very strong. You can pack as much or as little as you want into a crack like that. It looks pretty deep, if you fill it at least an inch deep all the way around it will take a lot of product. If you tried to do this with something more flexible like Sika or 4200, it would take cases of cartridges and make a horrible mess. You can fill it quick and easy with some fiberfiller.



Jarod

It would be easy to trim the exterior trim piece using a flush trim bit on a router once you have cleaned up all the rotten ply so the bearing has a fair surface to run on. I don't think I'd glass it. If you remove everything down to the teak stringers and glass, fill the gap, and then sand fair, the surface presented will allow you to bond the new cap on teak to teak, which is good for 5200. If you lay a biax over it first there will be a layer of glass between the cap rail and the stringers which may eventually delaminate, since it's glass on teak. I'd be happier with teak on teak and 5200 or 4200 FC.

[CharlieCobra]

Jarod, I hope she's inside cause we've rain coming in on us before long. I have a Mariner house to rebuild and need to get after it m'self before this weather window goes away. If ya get down to B-Ham, drop by and say hello...

[SkiprJohn]

Aloha,
I feel your pain. I've got much more of a mess that I'm dealing with at the present time. It almost was to the point where my decision might have been to scavange the gear and get rid of the wholefiberglass hull and go buy another boat or quit altogether.
You can work through this.
Charlie Cobra can give you many suggestions that you may never have thought of and he'll guide you correctly.
Good luck in your fix and the ability to stay out of the rain. We get 120 inches of the stuff a year here.
kind regards,