Chain Plate Caulk- Different Approach to Posing the Question

[rardiH36]

I know that questions about the best type of caulk for sealing the chain plate to deck joint has been covered many times. But I still am not successful at it. I have leaks every year. And in my last case, only a few months later the leak rate at one chain plate is as bad as ever. Just hosing down my boat results in a wet closet floor.

So I thought to pose the question differently: For those that used to have problems and then tried a new caulk, what was the successful caulk?

For my last attempt, in desperation, I dared to go non-marine. Background: 10 years ago, I had new rain gutters put on my roof. The contractor used a special caulk out of a typical caulking tube to seal the joints at the corners and downspouts. A decade of sun and weather and the caulk is still holding and in good shape. So I bought the same type of caulk at a roofers' supply specialty store to try on my chain plates deck joint. But the stuff hasn't stayed adhered to the smooth stainless steel. (On this, I have never used silicone caulk and also before my last application, I cleaned the surface repeatedly with acetone before caulking.)

My previous caulks have been polysufide and lifecaulk.

Ideas welcome!

 

[woodster]

I know that questions about the best type of caulk for sealing the chain plate to deck joint has been covered many times. But I still am not successful at it. I have leaks every year. And in my last case, only a few months later the leak rate at one chain plate is as bad as ever. Just hosing down my boat results in a wet closet floor.

So I thought to pose the question differently: For those that used to have problems and then tried a new caulk, what was the successful caulk?

For my last attempt, in desperation, I dared to go non-marine. Background: 10 years ago, I had new rain gutters put on my roof. The contractor used a special caulk out of a typical caulking tube to seal the joints at the corners and downspouts. A decade of sun and weather and the caulk is still holding and in good shape. So I bought the same type of caulk at a roofers' supply specialty store to try on my chain plates deck joint. But the stuff hasn't stayed adhered to the smooth stainless steel. (On this, I have never used silicone caulk and also before my last application, I cleaned the surface repeatedly with acetone before caulking.)

My previous caulks have been polysufide and lifecaulk.

Ideas welcome!

sand the back of the ss with course paper in order to creat a mechanical bond...and you may want to look at main sails butyl bedding tape for that application as well ....

regards

woody

 

[RichH]

Re: Chain Plate Caulk- Different Approach to Posing the Ques

Its not only the quality or the efficacy of the caulk that is important but the 'surface preparation' of the chainplate and the 'faces' of the chainplate 'hole' that count.

Chainplates 'move'/flex when under sailing loads and the caulk MUST be flexible enough to 'follow' such movement, the surface areas that the caulk adheres to MUST have sufficient 'tooth'/roughness to which to adhere, the caulk MUST be UV resistant or the Caulk must be covered with a 'cap'/plate (a 'pressure-cap/plate if you can'), the mating surface must be 'absolutely' dry and free of waxes/oils, etc.

Ive been a big fan of 3M 4200 UV, but am starting a trial of Butyl tape, etc. as even 4200 will release/leak after long term 'chainplate' service.

Its the 'prep' of the mating surfaces to which the caulk must 'stick', I think, is the most important.

 

[tkanzler]

I would add that you have to also look at how the caulk will flex when the chainplates flex. If it's bound up tight on three sides, it can't deform without potentially peeling itself off. That's one reason (of a few) why you use foam backer rod when caulking open joints in building structures - to allow the caulk to bond to the two opposite surfaces, but not a third, so that it flexes into a (_) in compression (top and bottom are adhered), and into a )_( when in tension. Just filling a big gap full with caulk won't hold up, as a general rule.

Not that I'm an expert in chainplate sealing or anything, of course. :neutral:

 

[RichH]

Re: Chain Plate Caulk- Different Approach to Posing the Ques

tkanzlers method should be well taken.
Another way that results in the same affect is 'reconstruct' the 'hole' with large bevels or chamfers .... \_/ , fill the 'void' with caulk and once the caulk is fully cured apply a screwed-down cap/plate that forces the beveled 'plug' of caulk down into the \_/.

 

[Steve Dion]

Re: Chain Plate Caulk- Different Approach to Posing the Ques

The butyl that is used to join the deck/hull joint in the Cherubinis is still flexible after 30 years. If you get quality butyl I think it MAY outlast the owners.

I think the key will be to get enough of the material inside the channel and on deck. I would clean out the area that goes below the deck surface very well before applying any material. This would go for caulk or butyl.

 

[tkanzler]

Another way that results in the same affect is 'reconstruct' the 'hole' with large bevels or chamfers .... \_/ , fill the 'void' with caulk and once the caulk is fully cured apply a screwed-down cap/plate that forces the beveled 'plug' of caulk down into the \_/.

I really like that idea. Doing that would, in theory, put the caulk in compression, always. As the chainplate deflects side to side, the caulk is always in compression, so the interfaces to the hull and chainplate are always in compression, and the bond is less likely to break, assuming shear isn't trying to separate them. Even if it did break, it's still in compression, much like a gasket.

The reason for doing what I described, which applies to buildings, is that as the surfaces move apart the caulk goes into tension, as does the interfaces, and you have to allow it to stretch without peeling off. Restraining it at the third side (perpen. to the opposite two) prevents it from flexing inward (necking down), and increases the tensile stress at the edges farthest away as all that deflection has to happen from the opposite side.

Your way is much like the deck penetrations for wire and cable, where you clamp the rubber stopper into it's wedge shaped base and it squeezes the cable.

 

[Maine Sail]

The chain plates on our CS-36 lasted for 32 years with butyl tape and were still dry when I took them apart. The chain plates were tested at a local machine shop who does metallurgical testing and found to be suffering from nothing. In 32 years none of them had ever leaked into the boat.

That being said some chain plates don;t lend well to butyl. You ideally need a through bolted cover plate though, not screwed down. Ours are physically welded to the chain plate and then through bolted to the 7/8" thick deck. CS never chamfered the deck holes, as Rich shows, or counter sunk the bolt holes. I did both after re-bedding them again with butyl tape. So they should last 64 years now..

Butyl works best under compression and if you can't get compression then it won't work any better than anything else. You also need ROOM around the chain plate for the sealant to move and flex. If the slot is tight the chain plates will leak. There is no escaping this fact..

As Rich said clean enough is never clean enough.

This is how they came out at year 32. Not one leak out of six chain plates.

This is showing the 7/8" thick solid glass deck before I chanfered the edges to create compression around the plate as the butyl went back in.

After applying the butyl, around the chain plate where it passes through the deck, butyl cones around the bolts and under the heads and tape under the cover plate, I then press them into the deck.

In order to really compress the butyl I use a block of wood and all my body weight. Once I feel they are fully compressed I then and only then tighten the cover plate nuts while not allowing the bolt to spin.

Clean up is easy. Just make a small ball of butyl and make quick really fast, Jackie Chan like, stabs at the butyl. When you pull the ball away the butyl that squished out comes with it.

Oh yeah and clean up takes all of about 40 seconds..

 

[Ed Schenck]

Re: Chain Plate Caulk- Different Approach to Posing the Ques

Silicone gets a bad wrap. I have never had a leak around my chainplates. It holds onto stainless such that you can barely get it off. And I do not prep the stainless. The problem I see with butyl is that our Cherubinis do not have a flat plate to squeeze the butyl. And you do not need a chamfer because the hole is already too big. Clean as deep as you can around the chainplate. Fill the void with clear silicone to above deck level. Screw down that cover and clean up overflow. No more leaks.

 

[rardiH36]

Thanks all. Great info and suggestions. I was at the boat today and unscrewed the chain plate deck cover plate off the most offending chain plate. Definitely on the interior side of the chain plate, it is hard up against the deck FRP with no gap/bevel to compress any caulk into. I will rectify this probably with a dremel. Also, I will be definitely placing an order of Butyl from Maine Sail.

Steve, you are right about the long life of the butyl tape that Hunter used on the older boats at the hull to deck joint. A couple of years ago, I tightened all of the bolts that fasten the two together via the toe rail. Probably the first time this was done since 1980. Butyl tape oozed out from the toe rail gap. Still pliable. I haven't had any leaks from the hull/deck joint since the tightening.

 

[Keiffer]

3m 4000

After numerous attempts at stopping chain plate leaks 3M 4000 with moderate compression did the trick (so far)