Chainplates and Bedding Recommendations

[Bets]

I am in negotiations to purchase a 1981 Sabre 30, which has evidence of leaking deck fittings at three chainplates. I know the rigging is dynamic and deck fittings must be rebedded from time to time, but in looking at Sabre's to buy, it seems that they are particularly vulnerable to bulkhead damage. Is it nothing more than the fact that Sabre's chainplates attach to wooden bulkheads, which are easily damaged by water than fiberglass? Also, this particular owner bedded with 4200 rather than Sabre's recommended 5200 because 5200 is so difficult. What do you recommend? Is the water damage simply a measure of the type of bedding compound used or not used enough?

[SkiprJohn]

Aloha and welcome aboard!
Lots of theories as to why chainplates through the deck start to leak. I would not use 5200 because it does eventually get hard and if your chainplates start to work a bit they will open a crack and begin to leak. Leaving a little bit of space between the metal and the deck glass and filling with a sealer like 101 or 4200 or 4000 makes sense to me.
kind regards,

[Butler]

Welcome to CF!
I agree regarding the 5200. I have used polysulfide(Lifecaulk) for bedding chainplates... has worked out fine... not an adhesive but it gaskets better than the 5200.
Straightforward sort of thing to remove, inspect and rebed the chainplates as well as the bulkheads.
Can check for damage to the bulkheads without removing the plates if needs be before you commit fully to buying and you might want to sound the deck around where the chainplates go through to find out if there has been damage to the deck core.
Check out the latest edition of Casey's This Old Boat. It's a very handy book to have around anyway, particularly if you end up shopping around some more. Plenty of threads to search here for work on chainplates also.

Good luck and happy sailing!

[Hud3]

I used GE SilPruf, and industrial quality silicone caulk, which was recommended by the boat manufacturer. Stays flexible and does a great job of keeping the water out.

[vet222]

Is the 3M 101 the same as the 3M Marine Silicone Sealant....... Thats what came up when I searched for 101 on the 3M site.
I ask this with regard to a previous entry on another thread pertaining to silicone based sealants tend to leave silicone contamination of metal and gelcoat and epoxy that make for poor adherence from any other products should the need arise to use something different.

My understanding from 3M website is that 3M marine sealant 4000 probably superior bit takes 7 - 14 days to cure whereas 4200 just 1 - 2 days for complete cure.

Comments?

[barnakiel]

If the chainplate is aligned properly and the seam area is thick enough, then polyurethane will seal very well. It does not have to be 5200. Any waterproof polyurethane sealant will do the job . Bostik, Sika, 3M, (i.a.) all have adequate products. I bet other materials will be just as adequate - I have seen polysulfides used and other stuff as well.

Where the seal fails is because there is too much movement in the plate (e.g. the plate not aligned, the plate too thin, the deck not supported properly, sogging, etc..) or else when the seal is not thick enough to allow for the movement there is. You can check out in the spec sheets for each product how much movement is permitted without the bond being affected.

When we used our boat extensively, we would renew the seal every year. But I think you can renew it much less often if the boat is used less.

b.

[Bets]

Thanks to all, great advice! The surveyor found some moisture around the a couple of chainplates and at two other spots unrelated to chainplates but to the steering pedestal and on the coach roof probably related to the handrail.

[zeehag]

as for bedding ANYTHING do NOT use 5200=---is NOT a bdding compound, is a glue. use 4200. 3m makes that for bedding compoun d and works quite well. welcome.. have smooth sailing and fair winds.