Joining Hull-to-Deck Joint Permanently with Fiberglass

[Redbeard33]

In the refit of my 1980 cherubini hunter one of the problems i feel most compelled to tackle first is the slight leaks on the starbord side above the settee, the obvious culprit is the chainplate and i plan to reseat that in 5200 as per recomendations on another thread. However i suspect that the hull/deck joint may be contributing a small bit, my concern is to fix one problem only to be faced with another especially when offshore as that is my sole intention once the refit is complete. In his book how to sail around the world Hal Roth describes the exact problem aboard his boat Whisper , everytime they would sail to weather water would weep in along this joint ruining clothes bedding, book, charts, provisions, cameras etc. he resolved this by removing the toerail outright and bonding the entire seam with 1, 2, 4, and 8 inch wide strips of fiberglass cloth respectivly in that order, he then belt sanded and faired it out and painted the hull and deck. considering the distance i plan on going the last thing i want is to live in a swamp for 2 years, I am basically putting this out for critique and suggestions, I have been a carpenter for 8 years and am very handy whilst I admit to not being an expert at fiberglass I have some experience and am not overly concerned with asthetics as long as it is dry and safe. Has anybody attempted this, and what were your results? Alternate techniques you have experience with? I have my ears open. As always thanks for taking the time to offer your 2 cents

[osirissail]

You would need to post some photos of what your hull/deck joint looks like. There are many different ways that manufacturers join the two. If there is a deck edge moulding that obscures the actual deck/hull joint that is one thing. Other manufacturers add wooden strips inside the hull and bolt the deck to that and then glass tab over the whole thing.

[Redbeard33]

here is a image from the original hunter owners manual, it looks hand drawn (precomputers), i will try to get pictures of the joint above and below deck as soon as i get a chance

[Northeaster]

Have you looked at the joint from inside?

Some manufactures glass over the joint inside, as well as sealing and attaching the outside flange together with bolts / machine screws and nuts, screws, or rivets.

I opened mine up, as it was 30 years old, and old sealant was dry and brittle.
Scraped out the old sealant, and cleaned joint best as possible.
Applied new layer of 5200 and through-bolted every 4 inches with machine screws (bolts) and low profile nuts (added 5200 to threads so they won't come off)
Mine was glassed together on the inside anyway, but it was not thick enough that I would have considered it truly structural on it's own.

Depending on extent of refit, and access inside, you may consider glassing together inside the cabin. I would remove toerail or whatever is cobering the outside flange, to see how it is constructed, and inspect the type and condition of the mechanical fasteners.

[Northeaster]

I would add that leaks can come from many other spots, like staunchions, chainplates, grab bars, cleats and other hardware.

Before heading offshore, I would really have someone soak the boat with a garden hose from every angle, while I was in the cabin (looking for leaks) until I was convinced I had fixed, or could libe with any leaks. Then I woudl take it out in some big waves and rain, and check it again!

[Redbeard33]

thanks for the response, no it is not glassed together inside, and it is blocked by bulkheads and trim in a few places which is why i abandoned the idea of reseating it, in order to remove the toerail about 1/4 of the bolts will have to be removed by cutting the heads off and punching them through (irreversible) i would leave about 4' on either side to give me the ability to move my jib blocks forward and aft, also i plan on reseating all handrails, ports, and stanchions and giving it the old hose test to double check

[osirissail]

I would suggest what you and a previous poster mentioned, redoing all the stanchions and any other deck fittings that are through bolted through the deck first.
- - Messing with the toe rail and its huge number of bolts is a very last step. One thing that can be done. If the bolts shown in the diagram in post #3 have heads or heads with a little bit of an edge - try to get a vise-grip pliers on the head and gently see of the bolt can be rotated. If so then probably the sealant is not longer attached to the bolt shank and water will pass down the shank of the bolt. Any suspect bolts can be replaced individually without having to replace all the bolts.
- - If that is not practical then surgically and chemically clean the bolt head and surrounding toe rail area and apply a good UV resistant adhesive sealant over the bolt head. That is assuming you don't really want to get into a major reconstruction of the deck edge and toe-rail.
- - If you can, using water, possibly colored - try to determine if there are gaps in the butyl rubber between the toe rail and the cabin top. If so, you can carefully grind a furrow down the inside of the toe rail into the cabin top a little bit and after cleaning well - lay a bead of adhesive sealant down that edge of the toe rail.
- - If the leak does not seem to be from the cabin top down then you are left with the joint with butyl tape between the FRG cabin top and the Hull flange. Here you would have to use a strong stream of water pointed up at the toe rail "overhang" to hull joint. This is where ocean waves lapping up the side of the hull could enter underneath the toe-rail and migrate through the cabin top to hull flange joint. Again a shallow groove, cleaned and then lay in a bead of strong adhesive sealant.
- - All of this is rather time and labor consuming and a lot of work. So investigate all the other possible areas where leaks could be such as "spider cracks," crushed FRG due to a repaired collision damage; deck fills; etc. The most common source of leaks is dried out sealant not sticking to the metal bolts anymore or broken free due to hull flexing.

[Shoalcove]

This may be of interest.
http://www.plasticclassicforum.com/viewtopic.php?f=4&t=4745&p=39882&hilit=FIBERGLASSI NG+TOERAIL#p39882