Jimmy,
What problem are you trying to solve? Can you be more specific?

Thanks,
Dave

I am curious myself. I was not aware of any design flaw with the chainplates.

Bruce wrote a very good article in the maintenance section...

[url]http://www.c36ia.com/node/134[/url]

When was the last time you rebedded them?

Jimmy:

I am curious what style of chain plates are on other boat, I know I have never looked. I usually rebed after 3 yrs, or the first sign of a leak, how tight to you have the rigging.

Randy

Jimmy,
I have an untested fix that you might be willing to try and perfect.

There are two reasons the chainplates leak. First, the gap between the chainplate and the deck is actually too narrow. Sealing materials are elastic. If the gap to be sealed is too small, there will not be enough sealing material to stretch and fill the gap when the chainplate moves. The adhesive bond between the sealant and chainplate fails and the gap leaks.
The second problem is that the hole for the chainplate is at deck level, so that any puddle of water on the deck has all the time in the world to wick into any small gap.

Here is how I propose to fix it. The steps aren't perfect yet, so you might have to experiment. a little. However, the basic theory is based on the excellent article recently posted on sealing deck fittings.

1) With a dremel tool, open up the top layer of fiberglass approximately 1/4" around the chain plate. cut down approximately 3/8-1/2" into the core. Do not cut the fiberglass on the underside of the deck.

2) Vacuum it out, let the core dry if it is damp.

3) Wrap butyl tape around the chainplate. taper it if you can, starting down below the fiberglass deck as far as you can reach. You want to to be at least 1/8" thick where the chainplate passes through the deck. Bring it up over the deck level at least 1/2" and add extra wraps to the part above the deck to make it thicker than the 1/8" at deck level.

4) Seal the chainplate from below carefully with tape. (Other methods may be better, this is one of the untested parts.)

5) Mix some unthickened epoxy. The lower the viscosity of the epoxy the the better. Pour this epoxy into the gap between the butyl tape and the enlarged hole in the deck around the epoxy. keep adding it until it is level with the deck. You want the epoxy to wick into every nook and cranny of the core, sealing it against water intrusion. You can see the importance of sealing the bottom!)

6) The next step will require some experimentation. The objective is to build up an epoxy pad on the deck the size of the SS cover plate, and approximately 1/4" high. This will get the chainplate hole out of the rain puddles. The way I was going to do this is to build a dam by cutting a cover shaped hole in a 1/4" silicone rubber pad. I was thinking of sticking the pad to the deck with silicone sealant. The silicone sealant will seal against the non-skid, and the pad will pull away nicely when the epoxy is cured, since the epoxy will not adhere the the silicone.

7) Assuming we are successful building the dam, mix thickened epoxy tinted either white or grey, depending on your preference, and pour it around the chainplate, until it is approximately 1/4" thick. Let it dry.

8) When the pad is dry, remove the dam, and cut the butyl tape off approximately 1/8" - 1/4" above the pad.

9) Force the SS cover down onto the pad. The butyl tape should squeeze out nicely from the top. Trim as needed.

10) Drill two screw holes into the pad, using the SS cover as a template.
Screw the cover down for the last time.

Building it up this way will put the butyl into compression, and will also ensure that there is an adequate amount all the way around the chainplate.

This is an open source suggestion, so please add to it and suggest some improvements.

Dave

Here's a tip about leaks.
We were on a one week cruise a short time ago. One late afternoon we had a very heavy downpour while at a marina and had to stay in the cabin. We discovered a leak around the mast and from one of the chainplates. There were no evidence of these leaks before this rain event. No streaks or water in the cabin.

My suggestion is when rain is predicted go sit in your cabin and look around during the rainfall. In our case the leaks were so new or so slight that they dried up rapidly in our hot Florida weather and went undetected.

Yikes, my '91 Mk I has never leaked to my knowledge. Am I lucky or just stupid? Don't see water or streaks anywhere, now I'm worried.:(

Mike

Mike,
Does it even rain where you are? In New England, I have plenty of opportunities to sit below decks while it is raining and look for leaks. That is when I am not standing at the helm, motoring in the rain.

Dave

[QUOTE=dwarburton;2667]Mike,
Does it even rain where you are? In New England, I have plenty of opportunities to sit below decks while it is raining and look for leaks. That is when I am not standing at the helm, motoring in the rain.

Dave[/QUOTE]

I think the song says [I]"It never rains in Southern California"[/I] right Mike?

This must be the time for leak discovery though. I was talking with a rep at Catalina Direct yesterday (looking for the window kit I ordered 3 weeks ago) and she said they have had a lot of requests lately for sealants and gaskets. And to make matters worse, they are having supply chain issues with the sealants. The grey sealant which comes with the window kits is back ordered. I had them give me the clear sealant instead so that they could ship my order to me. Not a project I am looking forward to but one that needs to be done before the heavy rains hit.

Actually Bill, I thought it never rained in Texas according to this past summer!! Just after I purchased our boat we spent a weekend inside due to the rain and we too discovered that we had some water was coiming in around the chainplates. I followed the iinstructions on the posting here to rebed them and fixed all of them and now it is dry as a bone.

[QUOTE=dwarburton;2667]Mike,
Does it even rain where you are? Dave[/QUOTE]

Actually, it did rain last spring. Unfortunately, it happened at night and I missed it.:D However, I have been below working on the laptop several times when the boat washing guys showed up, so I sat holed up below while they washed and hosed the boat (sorta like rain) and still haven't seen a leak. We have actually been in a drought here for a while. It's hot and everything is on fire. I'm looking forward to Winter. I think they're having it on a Tuesday this year.:D

Mike

Instead of reinventing the wheel, perhaps reading the "Good Old Boat" magazine would help. They had a very good article on chainplate bases a few issues ago. The owner of an older boat was experiencing the same issues we both have. What he did was to build up the area of the deck where the chainplates enter the deck to avoid water sitting there. Simple and effective.

Seems like leaking chain plates drive a lot of us crazy, me included. I spent A LOT of time resealing all three "chain plates" on one side this summer - one by one. After every repair I put the hose "on dribble" and watered each chain plate to see where the leaks were coming from. First the middle obviously leaked. I resealed it and then found the forward one leaked - the water actually came down the middle chain plate (NOT GOOD). I rebedded the forward chain plate and found it still leaked - it became apparent that it the leak was actually through the two deck bolts. Eventually I "solved" the leak by putting clear silicone on top of the deck bolts. For the past month - NO LEAKS and lots of rain. Obviously just a temporary repairs so Looking forward to attempting a permanent solution next summer but for now I'm throwing in the towel. At least I know now where I have to start.
Time to start winterizing up here.
Rick Verbeek
Hull #1763
Toronto

I have to agree with Jimmy, the chainplates on the 36 are not as good as the ones on the 28, certainly with respect to sealing them. The 28 chainplate has the big heavy part on top of the deck and you can seal it down very well. The plate below deck is much stouter than the thin cover plate on the 36. Our 28 was a 1990 and the chainplates had never been re-sealed since new but had started to leak a few months prior to us buying it. I think 16 years out of chainplate sealant is proof of a good system. All 3 chainplates go to the liner grid through tie-rods so no worries about rotting out a bulkhead. We reefed out the core around the chainplates, filled with epoxy and bedded with 5200 as had been done from the factory and had no issues in 3 years. Getting the 5200 out was no big deal there is a product that will dissolve it and I used that, though certainly I won't be putting 5200 on the 36.

We pulled the lowers out of Delaroux yesterday, it was obvious they were leaking and we wondered why the deck showed no moisture when we had her surveyed. Turns out one of the previous owners, likely the first one, had already reefed out the core at the openings and filled it with epoxy. So that's one job off my list already. Next will be the bulkhead attached chainplates, hopefully they have been epoxied as well.

I am considering building up the part of the deck around the chainplates as suggested above. But I am also wondering if part of the problem is that people are possibly screwing down the covers too tight and not leaving enough sealant between the covers and the deck?

I read that Sikaflex 291 is supposed to be a good sealant, very elastic but quite removable when necessary, does anyone have any experience with it? I definitely don't want a strong adhesive on those flimsy top cover plates.

I resealed my leaky chain plate on Saturday using the recommendation on the this website. I woke to rain on Sunday morning but no water coming in around that chain plate. I still have the windows to do, not really looking forward to that project and a leak around the mast partner.

There is a school of thought that says to bed the cover plates, screw them down to 1/16" from the deck, let the silicone cure almost fully, then give the screws another half turn or so to compress the silicone. It makes sense theoretically, but I always run out of daylight or patience before trying it.

[quote=dwarburton;2798]There is a school of thought that says to bed the cover plates, screw them down to 1/16" from the deck, let the silicone cure almost fully, then give the screws another half turn or so to compress the silicone. It makes sense theoretically, but I always run out of daylight or patience before trying it.[/quote]

Dave that is exactly what I did with the 28 and it seemed to work very well with 5200 which takes about 7 days to fully cure. I plan on trying a similar thing with this boat. I have been looking at sealants and Sikaflex 291LOT might be the one, it has less adhesive strength than 291 but is more flexible. It takes 5 days to fully cure so timing wouldn't be critical for the final tightening of the fasteners.