Tech Wiki

Rebedding Chain plates

Q: I'm getting some leakage through the deck from where the shrouds are mounted to the deck. In particular, the leakage is from the bolts (next to the chain plates) holding the tie-rods in place. Is it okay if I remove these bolts one at a time (or one shroud at a time) to re-bed them?

Chuck Hughes, Sand Save #223 (1986), Long Beach, CA

We just re-did the 6 chain plates using two 2 different methods. We had severe leakage into the cabin from the shrouds.

CONDITION 1: Rust stains on old bedding compound on in side of cabin.

SOLUTION 1: De-tensioned both stays (matching) and removed plate pin. Backed off tension rod in cabin and removed T bar. Removed top (deck) cover plate. Took a flex putty knife to cut old bedding out from under plate on cabin side. Key step is coming up next! Had wife stand on chain T plate while I cut remainder of bonds holding plate to cabin ceiling. Once plate was liberated we cleaned off all of the old bedding compound. The 3-year-old stuff was flexible but could see the water path into the cabin on the old residue. We saw failure of the bedding compound both on the vertical T plate portion of the chain plate and on the thru bolts. In some cases when we pulled the bolts out, the whole area was saturated with water and had drips into the cabin. This is with the last rainstorm 2 weeks ago. There was a lot of water to dry out of the deck matrix before we started reassemble. Reassemble, used 3M 301 bedding compound, apply new compound to plate and T. Ensure enough compound to provide complete coverage across the plate with no air pockets when re-compressed. An additional volume must be maintained for compound to act as a "thick" gasket. Insert T plate thru deck and install thru bolts. Remember to goop bolts with bedding compound at both the screw head and under the washer. Re-install the washer, lock washer, and acorn "cap" nut. Torque assembly to solid pressure. Do not over torque, you want bedding compound to form a gasket. The thinner the final compound is, the less the elastic range is. Reinstall T cover plate with bedding compound. Took an extra sharp applicator tip to fill in the voids between the T tongue and the deck hole. Final step, leave alone till hard. Do not wipe off excess till cured. I prefer to cut the excess after the "gasket" has cured. Re-Install shrouds and torque rod after 24 hours. Repeat procedure on next set of shrouds.

CONDITION 2: Water coming in but no visual distress on the inside-bedding compound.

SOLUTION 2: De-tensioned the stay if not already done by pair. Removed top cover plate and thru bolts from topside of deck. Clean off old potting compound from deck and top tongue of T plate. Reset bolts and plate as noted above. We just completed this operation 3 weeks ago on Anointed when we did the bottom. We did one set of stays a day and did a static tune a day before re-launch. We have seen no water leaks into the cabin or through the light fixtures by the plates, former big drip there. The procedure was about 2 to 3 hours a shroud set depending if the plates had to be totally liberated and reset.

T.R. Hernacki, Anointed #1298

My experience has been that some of the chain plates will begin to leak after a particularly vigorous sail with heavy stresses on the rigging and perhaps some flexing of the deck around the chain plates and bolts. Rebedding the cover plates and the bolt washers will stop any leaks for about 6 months. Six plus months later, after a vigorous sail, one or more of the leaks will reappear during a heavy rain or very heavy washdown. Thus far, only the two forward lower shrouds and one upper shroud have shown leaks. The leaks were slow drips from the top of the T-bar.

Bob Martin, SUNSET 1229

Done that. Loosen the shrouds, remove and recaulk. The removing is much easier said than done, especially the chain plate itself. Don't leave the leakage untreated too long. The deck is a plywood fiberglass sandwich so leakage is getting into the plywood as well as the interior.

Charles and Ba Holder

I can see that you're getting all kinds of advice. I'll add a few thoughts. I reseal/caulk with all the tension still on the shrouds. You need to DIG out all the old sealant and clean the area with alcohol and then with acetone/lacquer thinner. I find that poly sulfide works best for me. I tried to caulk when we've been on a sailing trip and it never held. Then I got smart and caulked on a Monday, let it completely cure and not sail (adding more tension to the rig), until Saturday. This works great and I haven't had to re-caulk in 5or6 yrs. Looking back – on the sailing trips I believe the caulk never completely cured. Hope this may help.

Ron Hill, Apache #788

I also had leaking on my boat a 92. When I removed the plates and bolts I found that I had water leaking into the plywood core. I dried that all up and to prevent any further damage used a "West System" kit of epoxy and filler and sealed the exposed areas of wood. The bolt Holes I drilled out to a larger size then filled them y with the epoxy and then re-drilled them to the original bolt size, then reinstalled the whole set up. Now I don't worry about the water leaking in....I figure that previously the water was leaking into the wood long before it ever showed up in side and was doing damage to the deck I just don't worry about it. When it shows up again I will just remove them and re-bed them without the worry of damage....I also used this technique with the bolts that attach the grab rails to the deck. Nothing has leaked since I did them about 5 years now.

Bill Quinn, Vita Brevis II