Chainplates...leaks

[Dan33]

I'm helping a friend attempt to solve leaking chainplates on a 32'er (below)...wood decks over cored fiberglass. Three shrouds per side.

I cut away the damaged teak around each chainplate (3x3" apx) then found most of the core wet or gone. We dug out the wet core, and the six areas have been exposed and drying for 3 months.

My question is...once this goes back together, is my goal to have some the chainplates able to flex where they come through the deck (4200??), or very rigid (epoxy with filler?? God help the next owner)??

My sense is a flexing seal, but I need some advice from this group.

 

[sailman]

I'm helping a friend attempt to solve leaking chainplates on a 32'er (below)...wood decks over cored fiberglass. Three shrouds per side.
I cut away the damaged teak around each chainplate (3x3" apx) then found most of the core wet or gone. We dug out the wet core, and the six areas have been exposed and drying for 3 months.

My question is...once this goes back together, is my goal to have some the chainplates able to flex where they come through the deck (4200??), or very rigid (epoxy with filler?? God help the next owner)??

My sense is a flexing seal, but I need some advice from this group.

A flexible seal, 4200, lifecaulk, etc. and a cap that can be removed to check on the seal periodically.

 

[creedence623]

I'm helping a friend attempt to solve leaking chainplates on a 32'er (below)...wood decks over cored fiberglass. Three shrouds per side.
I cut away the damaged teak around each chainplate (3x3" apx) then found most of the core wet or gone. We dug out the wet core, and the six areas have been exposed and drying for 3 months.

My question is...once this goes back together, is my goal to have some the chainplates able to flex where they come through the deck (4200??), or very rigid (epoxy with filler?? God help the next owner)??

My sense is a flexing seal, but I need some advice from this group.

A flexible seal, 4200, lifecaulk, etc. and a cap that can be removed to check on the seal periodically.

+1 The reason chainplates begin to leak is because the sealant ages and loses its elasticity, allowing water to seap in. Best practice is to seal the edges of the hole in the deck with epoxy so that when the sealant goes again the water won't ingress into the core. Then fit the chainplates if you removed them and generously apply sealant (not 5200!!) There should be about 1/8 of an inch space all around the chainplate if possible so you can ensure that you get enough sealant around it. Check out Don Casey's book, it's got a pictoral step by step for almost any repair you could possibly want to tackle. Good luck!

 

[Moonduster]

As per the above, you definitely want a flexible mastic for sealing your chainplates. Ditto on the advise about building a solid epoxy barrier that seals the core from the hole through which the chainplates pass.

What's not mentioned is that the mastic should be shot into the holes surrounding the chain plates AFTER the shrouds have been tensioned. With an older boat, and especially one that might be a bit soft, there will be enough hull deformation as you tension the shrouds that the mastic would be stretched to the limit (if not beyond) if you shoot first and tension later.

It also helps to sand the chain plates a bit so that there is a rough surface for the mastic to grip where the chain plates pass through the deck.

Good luck!

 

[Jose Carumba]

Gate,

If you are willing to do a little work here's a way to make the chainplates watertight. At least water will not get to the core. The only problem is that you need to have enough chainplate sticking above the deck for it to work, or make new chainplates and shorten the rigging.

CHAINPLATE.pdf

 

[Dan33]

Jose

I really like that...a bit of grief but a lifetime fix. I'll pass that on to the skipper.

 

[Jose Carumba]

Whoops! Typo in detail 1. Where it calls out "CORE" it should call out "TEAK DECK".

 

[Dan33]

Whoops! Typo in detail 1. Where it calls out "CORE" it should call out "TEAK DECK".

Jose

Didn't even notice that....verything makes perfect sense, but I get the idea that this also should be done with the rig stood and tensioned??

 

[Jose Carumba]

Whoops! Typo in detail 1. Where it calls out "CORE" it should call out "TEAK DECK".

Jose

Didn't even notice that....verything makes perfect sense, but I get the idea that this also should be done with the rig stood and tensioned??

I would just do the 5200 with the rig tensioned. Waxing the chainplate will let it creep a bit if needed without putting too much strain on the boss and deck. When you make the rebate for the 5200, make it as wide as possible (and don't forget to remove any residual wax on the chainplate in that area!). You might want to make it a bit deeper too by turning the 'glass up when it reaches the dam. The more 5200 there is the more flexibility you will have, and the bigger rebate also allows more bonding area for the 5200. The nice thing about this method is that it keeps the chainplate penetration above any rain on the deck (at least in a moderate rainfall) and doesn't allow any water near the core. 4200 might work as well as long as it got inspected regularly. It would definitely be easier to remove if you had to fix anything.

 

[Moonduster]

While I like the idea (nice detailing, too) of the raised epoxy island, I believe you're making a very big mistake by not allowing at least a 1/4" mastic gap all around the entire chainplate. The reason is that there is always some chain plate motion when the rig is removed and replaced - and in many boats there's motion while underway in a seaway. There is simply no way to prevent this. With an epoxy surround, as shown, the motion will crack the epoxy and cause leaks that can't be stopped without redoing the entire island.

To follow Jose's plan, I'd build a dummy chainplate from plywood that's 1/4" wider and thicker and use that dummy when building the islands. Wax it well and yank it out once the epoxy is cured. Then install the real chain plates and pump the void full of SikaFlex.

And remember, 5200 is a great product, but other than hull-deck joints and hull-keel joints, I'm not aware of any marine applications for the stuff.

Good luck!

 

[Jose Carumba]

While I like the idea (nice detailing, too) of the raised epoxy island, I believe you're making a very big mistake by not allowing at least a 1/4" mastic gap all around the entire chainplate. The reason is that there is always some chain plate motion when the rig is removed and replaced - and in many boats there's motion while underway in a seaway. There is simply no way to prevent this. With an epoxy surround, as shown, the motion will crack the epoxy and cause leaks that can't be stopped without redoing the entire island.
To follow Jose's plan, I'd build a dummy chainplate from plywood that's 1/4" wider and thicker and use that dummy when building the islands. Wax it well and yank it out once the epoxy is cured. Then install the real chain plates and pump the void full of SikaFlex.

And remember, 5200 is a great product, but other than hull-deck joints and hull-keel joints, I'm not aware of any marine applications for the stuff.

Good luck!

I bow to your experience Moonduster. The 1/4" gap is a good idea. Most adhesives need the extra width so they perform better in shear. If done your way one definitely does not want to use 5200!

I have to say though that I have seen 5200 used in through deck assemblies similar to what I have shown and it held up better than other sealants because of it's very tenacious grip, which of course makes it murder to remove. I guess I don't mind the prospect of digging it out down the road if I know it will last for a long time.

Somehow that reminds me that 5200 will degrade over time under UV exposure so it should be topcoated with paint or another sealant, or covered with an escutcheon plate to protect it from the sun.

When you are re-doing the chain plates and remove them from the bulkhead or knee or other structure to which they are attached, check the bolt holes in the structure and make sure they are not elongated. If they are you will have another job to do.

Oh yeah, don't ever get 5200 in your hair, and don't ask me how I know.

 

[Tucky]

My experience has been that none of this stuff actually sticks to the stainless chainplate, and the failure starts there. You can protect the core/surroundings, but then leaks into the interior have been my result.

Best luck I've had is Llifecaulk- the goo for starters and the liquid stuff periodically, while making sure it doesn't run into the interior.

 

[Ishmael]

My experience has been that none of this stuff actually sticks to the stainless chainplate, and the failure starts there. You can protect the core/surroundings, but then leaks into the interior have been my result.
Best luck I've had is Llifecaulk- the goo for starters and the liquid stuff periodically, while making sure it doesn't run into the interior.

Is that made in Wales, by any chance? In Llandudnow, perhaps?

 

[puddin]

so no one uses Sikaflex 291?

 

[Recidivist]

so no one uses Sikaflex 291?

I do!

I rebuilt the decks where the chainplates come through so they are now 100% epoxy glass, no core. The holes for the chainplates are oversize to accommodate a decent squeeze of sika into the gap. There is a dress plate that fits over the chainplate and screws to the deck - the sika between this plate and the deck is a major element in the attempt to water proof. I don't think tensioning the rig will move the chainplate much, it will increase tension above the deck, but there is so little scope for slack below deck that I can't see an issue arising. (edit: I should say, this is with my boat. A very soft hull may well distort)

For all that, discontinuous chainplates are the only "leakproof" system I've found - probably also the carbon systems where it's all above deck with no through fasteners.

 

[Pertinacious Tom]

Two suggestions:

As you rebuild the area where the chainplate goes through, make it a little high, so water has to flow uphill to get in.

Use butyl rubber as a sealant. It's the most flexible for the longest, far more than 4200. That's what is in sliding glass doors.

 

[cwa]

After reading this thread I am so glad that I have a steel boat!!!

 

[Dan33]

I have a friend with a steel boat...he loves working on it...and all he ever does is work on it!!

"rust never sleeps"