re sealing the deck to hull

[TarshishWS32]

I have a Westsail 32. I've removed all the old dry caulking from the deck to hull joint. Can I fiberglass it instead of recaulking? If I can fiberglass, how do I deal with the gelcoat?
Thanks,
Dennis McGill

 

[gonzo]

You need to grind the gelcoat off for good adhesion. Then laminate over the joint. I don't remember if the teak cap covers the joint.

 

[bregalad]

The deck had a flange at the top onto which a flange on the deck mold was supposed to sit. Ideally they overlapped by at least 2". There should have been something like 5200 between the flanges and a SS bolt every 6". The teak cap rail covered the whole thing, and the nuts, which are up inside the bulwarks would be very difficult to reach once the furniture was installed.

That's assuming it was factory assembled. If it had been delivered as a hull & un-joined deck ... no telling.

The problem with the later boats was that every time the fiberglass crew cleaned up that area with grinders they invariably touched the mold. Over time the flanges got shorter and shorter making it difficult to install the bolts. Properly joined parts out of undamaged molds shouldn't develop issues.

Does, or did, the joint on your boat look like my description.

I worked in the NC factory. My crew was the exterior woodwork. I shudder to think what a blank of teak for those S curves in the cap rail would cost today.

 

[viking north]

While the Halman 20 is a smaller boat it, like a lot of other designs has the same hull to deck joint subject to movement and leaks. I tackled the problem head on with a couple of Halmans. I glassed the hull to deck joint together first from the inside and then cut the outside flange completely away. Next I glassed and surfaced finished where the exterior joint once existed. The combination of exterior glassing bonding to the interior glassing made for a thick strong joint which allowed me to attach a rub rail. As well as being practical this broke up that rolled submarine looking deck edge.

 

[TarshishWS32]

Thanks for the help. It is a factory built boat. I have saved all the teak and plan to reinstall it. My first thought was to recaulk and reinstall the teak top rail. But then I thought is there a better way? It was a lot of time and work to get the teak rail off and clean out all the old dry caulk, so I want to be sure it won't leak again as long as I own the boat. That's why I'm thinking about fiberglass.

 

[bregalad]

I think I misunderstood the question.
The issue is the caulking between the boat and the teak cap rail, not the watertight or structural integrity of the hull-deck joint.

If that's the case you would still need some kind of bedding compound or sealant between the newly fiberglassed areas and the teak rail. Without bedding compound water will eventually get under the teak and cause problems.

Another issue would be that any appreciable thickness (say ~ 1/8") of fiberglass would change the shape enough that the joints at the S curved pieces would not go together. They are complicated to cut and fit and they come out of a thick, wide, pricey hunk of teak.

If the hull to deck joint is sound I'd re-bed the teak. That should be good for the next 10 - 20 years.

If there are problems with the hull to deck joint, that's a different and more complicated repair.

 

[TarshishWS32]

bregalal,

I think I confused you. It is a leak between the hull and the deck connection. water seeps into the interior of the boat. When I took the teak off, the caulk was dried out in the same spots as where the leaks were. So I took off all the teak to get to the joint between the hull and the deck. Now that I have taken ALL the caulking out I want to do something that will never have to be done again. That's why I'm thinking of fiberglassing the joint and then put the teak back over it.

Thanks for your response.

 

[JosephT]

A picture of the joint would help. The deck/hull joint is a pretty critical area. If you go with fiberglass, as gonzo points out sanding down past the gel coat to the fiberglass structure will give a good bond. Some good taping & masking will protect the existing hull & deck. Here's a thread from a sailor with a similar situation.

http://www.sailnet.com/forums/cal/67786-hull-deck-joint-ficaso-finished.html

 

[bregalad]

Here is a crude drawing of the joint as I remember it.

Does this look like your boat?
If so, I don't think fiberglassing is the answer. You can grind through the gelcoat on the top of the bulwark and get a good bond there .... and a reasonable surface area, but you won't get much contact area with the hull.

The only glass to hull contact area will be along the ~3/8" thick section of the hull that extends up, slightly above the hull flange.

There are three places where water can be getting in.
1.Between the mating surfaces ... i.e. between the bottom of the bulwark and the deck flange. The deck was supported by two chainfalls and lowered onto the goo covered hull flange. It was easy for a little movement during the process to create a goo starved area. They gooped it up pretty good, so this isn't the most likely scenario, but it would be the hardest to fix. You might be able to tell by inspection of the area if this is what is going on.

2. There could be leak(s) around the bolts that go through the hull to deck joint. If so you might be able to remove and re-install the offending bolt(s). If not you would just have to take extra care to bed well under the teak in that area and not squeeze the goo out when screwing down the cap rail.

3. The most likely culprit is the screws that secured the cap rail to the fiberglass bulwark. The top of the fiberglass was rarely flat. The goo was supposed to fill any irregularities. Over time there could well have been enough flexing to loosen some of the screws, and/or slightly enlarge the hole(s) through the fiberglass.

The good news is that this would be the easiest to fix. I believe the cap rail was installed with #12 self tapping screws. Use #14's when you re-install the cap rail and carefully plug the now larger holes.

I know you want a better, or longer lasting solution, but I can't think of one. Perhaps someone else can. But I don't see you having access to enough area on the hull to make a secure, long lasting fiberglass joint.

Edit: After I posted I noticed that my arrow somewhat obscures the extension of the hull above the hull flange.

 

[viking north]

My approach would be to loosen the fasteners wedge open the joint and more than ample fill that space with 3M5200, re tighten but don't over tighten the fasteners, (just slightly over snug) Allow the 5200 to cure for about a week after which snug it all down again, say 1 to 2 turns on the fasteners and i doubt you'll encounter another leak. However If it makes you feel good, you can also give it a layer or two of glass matt for good measure

A yacht is not defined by the vessel but by the love and care of her owner

 

[JosephT]

I concur with viking, some 3M5200 or other good marine deck caulking would do the job. You'll need to remove the old/dry caulking. Sharpen up a nice seal puller like the one below to remove the old caulking.

http://www.harborfreight.com/seal-puller-35556.html

 

[TarshishWS32]

Thanks for all the help

The drawing is exactly correct. I have decided to use a good silicone caulk after acitone cleaning the joint. I'll let that dry for a few weeks and then put a thin layer on just before the teak goes back on.
Thanks again from the Apostle Islands.

 

[viking north]

MMmm --silicone caulk ?? wouldn't be my choice -- 3M5200 or Sikkens marine caulk I believe is butlated (spelling ?)rubber which is from my experience far superior. I personally gave up on silicone for exterior use years ago, just didn't have good luck with the stuff.

 

[PAR]

Agreed, silicone caulk is for your home's bathtub, not your boat. You'll want a polyurethane or butyl rubber instead. Silicone has few uses on a boat and can make painting and other finishing operations imposable.