deck to hull seam issue

[Cevin c Taylor]

A few weeks ago I noticed wetness on the inside of my '83 CP16, on the starboard side, right around the area where the tangs for the shrouds go through.  It's not enought to even dribble down the inside of the hull; just enough to moisten the wood covering the inside of the seam.  I assumed that my hull/deck seam was coming apart.  his weekend was hot enough to get the rub rail nice and pliable.  I pulled it back, and all in all, things look pretty good.  The rivets are in place and appear to be fine.  What appears to be a tape of some sort was covering the seam.  I did not see any open areas that looked like they would let water in, except behind the tang (I think that is what the ss strip is called).  There appears to be a small gap where the sealant between the deck and the tang is.  I really don't want to pull off the rub rail and overdo things.  I'm thinking of just cleaning up the area behind the tang as well as I can, and then using some 3M 4200 or 5200 (I have both) behing that area - trying to get it in with a screwdriver or something like that.  Any thoughts?

[wes]

Wolverine - that tape is applied at the factory as a convenience to allow them to install the rub rail and finish building the boat while the 5200 adhesive is still curing. It doesn't have any purpose after that.

In my experience, the hull to deck joint is very solid on most Com-Pacs and relatively unlikely to leak. Can't say the same for the chain plates, which I think is what you mean when you say tangs. The force and movement of the rigging can open up the seal around the bolts and allow some leakage, and the slot where the chain plate passes through the hull to deck joint is also a weak point. The chain plates themselves can also develop stress cracks or hidden corrosion over the years. Leakage of a little water inside the boat is an annoyance, but failure of a chain plate under sail could really ruin your day.

On a 1983 boat, my advice would be to remove both chain plates, inspect them carefully and replace if they show any signs of fractures or corrosion (they are not expensive; Hutchins keeps them in stock in the parts department), then carefully re-bed them with your favorite sticky stuff. I am partial to 3M 4200 because it's easier to remove in the future, but some on this site prefer 5200 or one of the BoatLife products. There are tons of previous posts on the subject here on the site.

I like Debond "Marine Formula" to loosen up the original 5200 that the chain plate bolts are bedded in, and then to clean up any remaining bits inside the bolt holes. It is like Kryptonite to 3M 5200; slow to act but it breaks the chemical bonds and leaves the 5200 huddled on the floor begging for mercy. You can buy it on-line from various suppliers; I order mine direct from the manufacturer (www.marineformula.com) because they have very reasonable shipping fees. When you're done, you should neutralize using alcohol or soapy water, to stop the chemical action. And be careful not to let it soak into the hull to deck joint, because you don't want to deactivate that bond.

I did all this on my 1988 boat. My chain plates turned out to be in good shape structurally (others haven't been so lucky) but the re-bedding stopped the water leaks, and I sleep a lot better at night.

Wes

[MacGyver]

Wolverine,

I am a boat tech at a marina in Southern Illinois, I am one of the guys Wes speaks of with a vote for the boat life products, specifically called "Life Caulk".
It is my personal preference just because of its ability to be rebedded easily in the future, and its flexibility between different materials.
I would look at all the different products and see what suits you best, and with the help of a friend or well placed vice grips you can do all that work yourself easily.
One thing I highly suggest is prep work! tape around the item before you start so when you clean up the oozed out materials, you end up with a clean install, and also cleaning the area really well before starting will help with a more solid install and hopefully a longer lasting seal.

Mac

[Cevin c Taylor]

Thanks for the advice.  I am hoping to take the boat out this weekend, and so I probably won't get a chance to do any sealing before that.  However, I will inspect the chain plates carefully before heading out. 

[jeffcom16]

Funnily enough I have just had the same problem. My boat is 1969 and had been left alone for over a year with leaks, so have been busy fixing them , repairing the wood and repainting.
I could not figure out where my starboard leak was coming from as there were no deck fittings above the area. I decided to take the rubrail off, rake out sealant and replace with new. It did appear to do the trick as I now have a dry boat.
I plan to pull my boat in a few weeks and will replace the whole rubrail and re caulk all around.
good luck