I re-bedded my chain plates... its not difficult but you'll need someone to help you... one to hold the bolts from the top and one with a wrench in the cabin. I just unfastened the stays (one at a time), banged the bolts up thru the deck, cleaned everything off and then resealed. I put tape around the deck fitting so whatever sealant oozed out didn't get on the deck.

Hi Ken...

I did this about 7 years ago so some of the details are fuzzy but the bolts and chain plates were fine; I didn't replace anything. There is a solvent you can get from West Marine to spray around the rigging where it goes thru the deck to loosen the sealant that is there but the name of it escapes me at the moment. If you go to West I'm sure they will know what it is.

The nuts came off from the inside. I had to get my wife to hold them steady with a large screwdriver from the outside while I unscrewed them from the inside. I then tapped from the inside to get the bolts to come out on the deck. Don't mash them and bend the bolt or damage the threads. I used a small block of wood to actually tap on rather than directly on the bolt, until the bolts broke free. I used BoatSeal or BoatLife. I forget which since the names are so similar. If you read the package you will see which is better for this project. I have not had any problems since. 

Its not really a big or time consuming job. You will want to get all the old sealant out before resealing to make a tight seal though. That could take some scrapping.

Regards,
 

Debond Marine Formula is the solvent I like to use to break the old adhesive sealant, but there are others.  I did this job a couple of years ago on my chainplates by myself somehow.  I seem to recall using vice grips on the nuts below.  Grip it to a nut, turn the screw up top until the handle of the vice grip hits a wall and then you can tighten the screw.  Lots of up and down the ladder that day.

Hi,

we have a 1993 '36, hull 1237.  We have had to deal with this situation too. A couple points:
1. I would not expect riggers to address this, so it is up to you to address it.  

2. Unless they changed the deck structure you have a plywood core sandwiched between two layers of fiberglass.  I would recommend that you pull off the chain plate cover on deck completely including removing this bolts.  You want to determine whether the plywood core is wet around the chainplate itself or around the bolt holes.  It probably is.  If so, I would clear out as much of the wet core all around the chain plate as as you can.  

3. Then, use a larger bit to over drill the bolt holes. Tape some thin plastic, like from a fresh spinach box to the underside of the bolt holes. Then fill the bolt holes completely with epoxy and tape a piece of plastic over the filled holes. After the epoxy is cured, remove the plastic and drill new holes for the bolts through the epoxy. Now you know the core will never get more leakage from the bolt holes.

4. Use a similar approach around the chain plate. Here make sure you have surrounded the chain plate completely with plastic to ensure you don't accidentally epoxy the chain plate to the deck. Again put plastic below where the chain plate comes through the deck, fill the void with epoxy and cover the top with plastic. Once the epoxy is cured, remove the plastic.

5. Now you are ready to reassemble.  Get some butyl tape (West Marine) and surround the chain plate with the butyl tape, filling the gap and leaving a small amount just above deck level. Counter sink the epoxy at the bolt holes. Finally, put the bolts through the cover and wrap enough butyl tape around the bolts on the underside of the cover so that it will fill the countersink. Now reinstall the plate and tighten down the the bolts. 

Having done the above, you should never have to deal with that chain plate leaking again 

Now, you need to check out the wood around the chainplate where it is bolted to the bulkhead in the cabin. You will want to repair any wood that may have rotted because of the leakage. 

I hope this helps.