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mikehoyt 08-18-2003 08:58 AM

Sealing Chainplates
My portside chainplate has recently developed a leak that is prevalent when sailing in windy conditions with water washing the deck. It is not noticable in the rain.

The chainplates were sealed with 3M 4200 a year ago but it seems not up to the task. What is the best "proper" method for sealing this before it causes irreparable damage to deck and bulkhead?


knothead 08-19-2003 02:42 PM

Sealing Chainplates
Are your chainplates mounted outboard or through the deck? If they are through the side deck there should be a rectangular plate which is notched for the chainplate with screws to attach it to the deck. Usually you would only need to remove that plate and rebed it. If the leak has existed for awhile you should look for "bleeding" below. If there is evidence of much rust, you would be well advised to remove the chainplate for a thorough inspection. If the chainplates are outboard you need to remove, inspect and reinstall them.

mikehoyt 08-20-2003 06:55 AM

Sealing Chainplates

They are thru the deck on the side deck. I have removed and rebedded this plate at the end of last season. It has started to leak again. Did not leak first season but then I refinished the deck. Not sure if leaking is thru the screw holes or beside teh chainplates.

I am assuming the correct "best method" is to clean out all current bedding compounds and use epoxy to create a rot free entrance into the boat. Then rebed. Just looking for suggestions and or confirmation.


GordMay 08-20-2003 08:32 AM

Sealing Chainplates
You got it! There ain''t no easy way.

pirateofcapeann 08-20-2003 09:51 AM

Sealing Chainplates
This is a responce I wrote for another message a while ago:

Who ever came up with the silly idea to run the chain plates up through the deck should be keel hauled… the long way! But as you’re probably not ready to mount phosphor bronze, Herreshoff style chain plates to the outside of your pristine white fiberglass hull, we’ll have to try to correct the problem as it stands.

I faced the same problem on my C22. Over the years, water running down the chain plates had caused the wooden bulkheads to rot out. Although I replaced the bulkheads, I wanted to find a way to keep from having to do it again. I sealed the new bulkheads in multiple coats of epoxy as well as the chain plate bolt holes and bedded the plates and the doublers in epoxy too. But what I really wanted to do was to stop the deck joint leak.

First you need to understand what you’re trying to do. You’re trying to seal a joint between two pieces that move independently of each other, ie, the chain plate and the deck. The movement between these two is caused by the alternate loading and relaxing of the area and the rigging. Although in most cases it’s very slight, it still will eventually break down the bond that any chalking may make on the two, unless there is sufficient space for the chalking to flex properly.

I would suggest that you remove the plates, first marking the position where they exit the deck. Also, if the dirt line is gone, mark the area covered by the cover plates as for esthetic purposes, you don’t want the repair to extend beyond this. Mark a cut line ½ inch around the surfaces of the chain plate, leaving ample material for the cover plate screws to bite on. Cut this area away, right down through the deck, being careful not to damage the mounting brackets for the plates below. Once that’s done, thoroughly clean and dry the area.

If moisture is present, you can use heat lamps and acetone to dry it out. Then seal the core, deck and inner pan surfaces of the cut out with fiberglass. I would use epoxy instead of resin for this, as the repair area will be small. Don’t forget to run some epoxy into the cover plate screw holes with a pipe cleaner.

Once the repairs are cured, clean the inner faces with a file, acetone and a scrunge pad. You want to get these surfaces clean and free of wax so the chalk will bond. Use a sander on the deck so the cover plates lay flat and below to clean up the over-head as well. Clean the chain plates and their mounting surfaces below. Use a wire wheel on the sections that pass through the deck, and re-mount the chain plates and doublers. I bedded mine in epoxy but 5200 may work here just as well.

Now, from below, tape off around the chain plates at the overhead then take your 5200 topside and fill the voids around the plates well. A plumber’s acid brush may help make a better mechanical bond to the fiberglass and the metal as a first step, then fill ‘em up!

It takes about 7 days for 5200 to cure. It expands a bit as it sets and here is where you’re going to put the final finish on your fix. Using a sharp chisel cut off the excess about ¼ inch below deck level at the chain plate. This will give the 5200 some flexing room before it hits the cover plate and is stripped off. Put the covers back on and you’re done! They should give you years of leak free service. Mine were still dry when I sold Olde Blue four years later.

Well, I hope this response wasn’t too exhaustive and is helpful to you. Good luck!

mikehoyt 08-21-2003 08:05 AM

Sealing Chainplates
Thanks Pirate!

That is about how I expected the repairs to go. The idea of epoxy in the bulkhead below is a nice touch!


KenD 08-25-2003 07:26 AM

Sealing Chainplates
Here is another thanks to the pirate. Starboard chainplate leaks will fix it myself now. Sounds like a good fix. for a little better seal don''t tighten up on the 5200 bond until it''s cured then the elasticity of the caulk will work for you makeing a nice gasket type joint.

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