Chainplate Failure! Typhoon Weekender

[greh3595]

I think Oswego John and Sharkbait are both on to something here. It is unfortunate that such an important structural element on these boats cannot be practically inspected. The only thing to do is periodically try to back the bolts out and inspect for corrosion. In my case, I'm the original owner and I'm therefrore confident the bolts were installed by CD. But they never showed any visual signs of corrosion (rust in my case as mine were stainless steel).

Someone mentioned that the system is not technically a chainplate system and they are correct, but then what better to call it?

In my case as a result of the "chainplate" system failing under load, I now have a damaged "chainplate" needing repair. Does anyone know where I can source new parts or can anyone recommend a reputable machine shop to fabricate new ones using the damaged one as a template? It appears several different "chainplate" systems were used over the years of production, but I assume any of them will work. It appears that CD went away from the high quality cast bronze in the later years to save costs.

If anyone can tell me how to post a picture to this forum, I'll get a picutre of the now exposed rust and damaged "chainplate" posted for all to see.

[Sea Hunt]

Somewhere on this board I seem to recall a Cape Dory sailboat (possibly a CD 27, 28 or 30) that was modified for blue water sailing. The owner had moved the shrouds to the outside hull with traditional "chainplates" bolted into the side of the hull, etc. as I have seen on some bluewater sailboats as "factory" installed" - Lyle Hess cutter, possibly Dana 24, etc.

I am wondering if this is something that could be done on our Ty Weekenders I am not sure of the esthetics or the mechanics/logistics of trying to do this. I assume it would require new standing rigging because the rigging would be longer.

Any thoughts

I plan on doing what I can to inspect mine - short of digging into fiberglass or unscrewing bolts that do not visually appear to be "rusting". However, if I do not sell S/V Tadpole (I remain actively searching for a CD 25D), this Fall after "H" season I had planned to haul her for bottom paint job, replacing seacocks, etc. I would consider repositioning the chainplates at that time depending on the wisdom of this board.

Thoughts on moving the chainplates outboard

[Oswego John]

Thoughts on moving the chainplates outboard

Nah. It's like putting fender skirts on a vintage MGTD.

O J

[sharkbait]

I would not change to conventional chain plates. That would destroy a classic boat.

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[Numbah134]

The chainplate is not the problem here - the bolts are, and perhaps a poor choice of materials for what the bolts go into (ie, using mild steel rather than stainless steel reinforcements in the fiberglass). Add salt water, stir & wait.

When you haul out, yank the bolts. If the bolts come out and look OK, you've checked (no visible corrosion was the case up to failure, remember? So if you don't yank them, you won't know until it's too late.) slap some antisieze on them (and perhaps some sort of sealant under the plate) and reinstall.

If they look bad, replace.

If they break because they are frozen to the hardware below, they are corroding and you do what you need to to remove what's left of them, repair the damage, and replace with new bolts in a manner less likely to corrode, before you have an incident that increases stress on you and bends your chainplate in the bargain. Repeat in 5-10 years. Far better to break a compromised bolt at the dock while trying to remove it than while sailing. Just budget 3 times more time for the job than you expect it will take, double that, and then expect it to take longer.

'tis the way of working on old things.

[mgphl52]

Thoughts on moving the chainplates outboard

Nah. It's like putting fender skirts on a vintage MGTD.

O J

My sentiments exactly!!! There was CD30 ketch around here years ago that had been "de-graded" to outboard chain plates. To make something ugly look even worse, the rub rails sections didn't even line up...

-michael

[greh3595]

Numbah134 has the right ideas here. On my boat, there was no visual warning of the bolts rusting. They looked like shiny stainless steel above and below deck where they were exposed. I think the problem (corrosion) may have started with what CD used for reinforcement. According to the detail Sharkbait posted, there is a piece of steel sandwiched between the bottom of the deck and the liner where you cannot see it. My bet is the CD used mild steel here and that over the years in the hot humid environment of Florida where the boat has spent all its life, that steel has rusted, seized the bolts that penetrate through it and eventually allowed rust to occur in the shafts of the bolts themselves. All of this not observable without destroying the fastening system to get at it.

I'm thinking about just completely abandoning the existing bolt holes and locating two separate bronze chainplate casting as depicted in Sharkbait's sketch. I'll drill all new holes (two per chainplate/shroud) a little oversized and fill them with epoxy and then redrill them to exact size as Sharkbait suggested. This should keep the new bolts from coming into contact with the rusted piece of steel backing that is probably in there. Then I'll finish it with a new stainless steel backing plate on the underneath side exposed where I can see it. This way I've got stainless steel bolts running through bronze fittings at the deck level that should only be contacting the stainless steel backing plate under the deck. All of this should be very observable and inspectable. To aid in that, I'm going to cut a much large inspection hole than the little 5" one the factory provided.

Any comments on this system would be appreciated. Also any thoughts on whether to use 3M 5200 or some other product to bed the chainplates to the deck would be appreciated. Some have advocated anti-seize, so if there is a specific product recommendation on that it would be most helpful. Also, anyone know where I can find some nice bronze chainplate bases that would accept a 1/4" clevis?

[Sea Hunt]

OJ, Mike, Sharkbait and all.

Message received loud and clear. I will not move the "chainplates" but I will carefully inspect the bolts and nuts when she is hauled out this Fall.

Candidly, I liked OJ's analogy best.

It's like putting fender skirts on a vintage MGTD. O J

Many, many years ago I owned a 1958 Triumph TR3A and later a 1967 Austin Healy 3000 Mark III. Classics then; classics today. I would not have changed a thing on them. I will not change anything drastic on S/V Tadpole.

These days, I drive an old Chevy truck with a little over 201,000 miles on her.

[John Vigor]

Somewhere on this board I seem to recall a Cape Dory sailboat (possibly a CD 27, 28 or 30) that was modified for blue water sailing. The owner had moved the shrouds to the outside hull with traditional "chainplates" bolted into the side of the hull, etc. as I have seen on some bluewater sailboats as "factory" installed" - Lyle Hess cutter, possibly Dana 24, etc.

I am wondering if this is something that could be done on our Ty Weekenders I am not sure of the esthetics or the mechanics/logistics of trying to do this. I assume it would require new standing rigging because the rigging would be longer.

Any thoughts

You're probably thinking of Fenix, Fred's old CD28. He moved the chainplates outboard and then circumnavigated the world. What does that tell you?

Cheers,

John V.

[bill2]

My failing memory seems to tell me that Fred got some of his hands on in SoCal ? ? ? Could be wrong though . . .

Isn't SoCal the original home of Pacific Seacraft ( bastion of external chainplates ) though now they may be in NC ?

Course I don't want to be in the middle of a Crealock -v- Alberg controversy . I'll just say I wouldn't hesitate to own a boat by either ( assuming of course that I won a lottery

Good Luck with those chainplates

[Markst95]

Be thankful you have a CD and only worry about Chainplate bolts. My last boat I always worried about my Keel bolts!!!

[Troy Scott]

Drew,

Has anyone mentioned Spartan? They made a lot of the hardware for Cape Dorys, and they are still in business.

As for the backing plate, If I were in your shoes I would use prefabricated FRP. It's relatively easy to use and to machine to the right shape. In the unlikely event that you can get the steel out in a way that preserves the fiberglass that held it on place, you could just slip the new FRP piece in where the old one was. You would need to bed it in thickened epoxy. Even if you manage to do that, you would do well to add yet another, even larger plate below the original one, to better distribute the load. This one would also need to be bedded in FRP. Take care to install it so that the plate is perfectly parallel to the bolts. Of course the new bolts will need to be longer.

If you decide to use prefabricated FRP to replace the steel backing plates, be sure to completely sand the surfaces before bonding, and use enough reinforced epoxy resin to completely fill all voids.

[Lang]

My chainplates popped out when I raised Eleanors' mast in 2004. It was my 1st time raising mast and may have gotten the shrouds too tight. Was good to have that problem happen to me then, otherwise it would not have occured to me to check.

On investigation, found the stainless bolts were completely broken, but the chainplates were fine. BTW, the chainplates and backing plates were stainless from Shaeffers. They had the Shaeffers stamp on them. Something the previous owners did..?

My fix was, to install Silicon bronze bolts and nuts which I ordered from Jamestown distributors. So far, it has work very well. No more corrosion problem.