CD27 chainplate condition, maintaining/replacement, example

[BrandonL]

I have what seems to be surface rust on my chainplates, but I would like to get opinions from more experience CD owners. Here's the worst of what I have discovered on both sides...


[port]


[starboard]


[video of scratching with screwdriver]

I poked and scratched at it with a screwdriver and it seems very solid, but based on examples shown here:

https://blog.tonybishop.org/a-chainplat ... -surfaces/

I see that the top of the plates are worse, and I'm wondering how much time I have before replacement will be necessary on mine.

With the very limited access to these areas, is there a way to slow/stop the portions of chain plate that are rusting?

The plates seem to be very solid, but now that the rust has started, how long before I need to start thinking of replacing them?

I'm looking for opinions from people with experience in this area and example pics and fixes that have been made so I can begin to plan for future needs. Thanks in advance for your comments.

[jbenagh]

These look pretty normal. That cold steel is going to get surface rust no matter what.
In the starboard picture, it looks like you might have a little water intrusion near where the bonding wire is attached. You might consider rebedding that chain plate on deck. It could just be condensation though.
You might want to refasten the bonding wires after sanding them down. You could check them with an ohm meter to see if the connection is still good. If it's greater than a few ohms to the bonding plate there's probably corrosion somewhere that you should address.
Jeff

[Jim Walsh]

What year is your boat? Based on the rate of corrosion you have a few options available. If you have no plans to cruise extensively or offshore you may want to leave the backing plates/assembly in place and coat the exposed area with a rust converter. You can also remove your chainplates, rebed, and replace the fastenings.
If you would not be satisfied with that then you must consider one of the alternatives permanent solutions offered in your attachment.
This is the diagram included in your attachment which I think is sound advice. Once modified and completed you would have an improvement over the original build.

[BrandonL]

Thanks for the responses.

Jim, it's a '77 build. I would like to eventually cruise extensively but will have a few more seasons here in Lake Michigan prior to taking off for more distant salty horizons. I accept that I'll probably want to improve upon the existing chainplate situation, along with some work on the rudder/rudder shoe, and probably several other improvements and safety measures in order to feel more confident in a more live aboard, offshore cruising situation.

[JD-MDR]

I used 1/2" g-10 for under deck plates and a knee brace under each deck plate/padeye.. I read of one guy on the forum using carbon fiber . it's all in the archives.

[SVFayaway]

I'm the one who opted for carbon fiber. In retrospect I would use regular glass since carbon fiber is stiffer than the e-glass used in the hull and so it will take the full load of the chainplates first making it more susceptible to fatigue. That said, I think what I did was a little overkill and I don't expect to have any problems with it. I plan to keep an eye on the situation and if it develops problems (failure of the carbon fiber at the hull-deck joint) I'll install G10 knees. Honestly I think that a simple fiberglass reinforcement using a heavy cloth like 1708 in staggered layers, with a full length G10 backing plate replacing the steel plate, would be ample for a smaller Cape Dory.

[fmueller]

I would suggest a couple of pilot holes drilled thru your plates in a few spots. That way you can determine the extent of oxidation - ie surface or more serious. That will inform you if you actually have an unavoidable as opposed to elective replacement problem. In the event you discover you have most of the original mild steel intact and that the oxidation is mostly surface, you could then choose to leave well enough alone.

Except you would then want to make absolutely sure you have no moisture ingress from your chain plates. You should re-bed them. That’s something that should be done anyway on a boat of this vintage.

I did exactly this on my 27. My backing plates looked a little better than yours but still when I first laid eyes on them I thought they were trashed, but that was just not the case. The OEM finish is really messy and does not inspire superficial confidence. Add surface rust and it looks like a disaster. But I actually think it’s pretty robust. My chain plates have since been re-beded and there has never been a hint of leaking. I also replaced my original standing rigging and now don’t worry about that aspect of my boat anymore.

Cheers


Edit. . I’ll try to post some shots of my 27 chain plates.

[BrandonL]

Hey all, thanks for sharing.

These look pretty normal. That cold steel is going to get surface rust no matter what.
In the starboard picture, it looks like you might have a little water intrusion near where the bonding wire is attached. You might consider rebedding that chain plate on deck. It could just be condensation though.
You might want to refasten the bonding wires after sanding them down. You could check them with an ohm meter to see if the connection is still good. If it's greater than a few ohms to the bonding plate there's probably corrosion somewhere that you should address.
Jeff

Jeff,
I'm glad these look somewhat normal. I am currently in a fresh water environment (JuJu is on her cradle covered with shrink wrap), so if that's just surface rust, which I believe it to be too (deck isn't bubbling up above them), this will probably buy me a bit more time. I am inclined to think it is just surface rust from condensation but if I ever intend to do any long distance cruising, I'll want to come up with a better solution. That little bit of wetness shown in the photos is probably due to me having a heater running and be being aboard for about an hour prior to taking the pics/video on a rapidly warming morning after a freezing cold night.

As far as bonding wires go, are you saying to sand down the connection points and test for ohms at the bonding plate outside on the keel (before unattached, when unattached, and after reconnected)? I'll need to get better informed about the bonding system and navigating that system.

I used 1/2" g-10 for under deck plates and a knee brace under each deck plate/padeye.. I read of one guy on the forum using carbon fiber . it's all in the archives.

Thanks, JD-MDR. I'll be checking out more of the archives. That G-10 seems like the way to go, but not a small job in the least. I assume you're feeling very confident in your plates now.

I'm the one who opted for carbon fiber. In retrospect I would use regular glass since carbon fiber is stiffer than the e-glass used in the hull and so it will take the full load of the chainplates first making it more susceptible to fatigue. That said, I think what I did was a little overkill and I don't expect to have any problems with it. I plan to keep an eye on the situation and if it develops problems (failure of the carbon fiber at the hull-deck joint) I'll install G10 knees. Honestly I think that a simple fiberglass reinforcement using a heavy cloth like 1708 in staggered layers, with a full length G10 backing plate replacing the steel plate, would be ample for a smaller Cape Dory.

Thanks for this insight, SVFayaway.

If you have no plans to cruise extensively or offshore you may want to leave the backing plates/assembly in place and coat the exposed area with a rust converter.

Jim,
Being that this upcoming year will be my first season on JuJu, I'm hesitant to have any solid plans with this boat, but I do foresee wanting to get it ready for some bluewater (potentially singlehanded) cruising in the not too distant future. I have said that I'd like to shove off when I turn 50. I have 3 more years to prepare before said shoving off.

Is there a standard rust converter recommended for this situation?

I would suggest a couple of pilot holes drilled thru your plates in a few spots. That way you can determine the extent of oxidation - ie surface or more serious. That will inform you if you actually have an unavoidable as opposed to elective replacement problem. In the event you discover you have most of the original mild steel intact and that the oxidation is mostly surface, you could then choose to leave well enough alone.

I like the pilot hole idea, Fred, but I'm not quite sure how to go about it. There is very little access where the rustiest looking spots are (actually very little access to the entire plate really, as I'm sure you know). I took those pics by blindly sticking my phone through a 3-4" dia. access hole. Would you suggest cutting out a larger hole to perform this? How large/deep of a pilot hole and how many are safe to drill without weakening the plate? I would aim for the rustiest areas. Should I then cover them with rust converter and fill with epoxy, or something else?

Except you would then want to make absolutely sure you have no moisture ingress from your chain plates. You should re-bed them. That’s something that should be done anyway on a boat of this vintage.

I did exactly this on my 27. My backing plates looked a little better than yours but still when I first laid eyes on them I thought they were trashed, but that was just not the case. The OEM finish is really messy and does not inspire superficial confidence. Add surface rust and it looks like a disaster. But I actually think it’s pretty robust. My chain plates have since been re-beded and there has never been a hint of leaking. I also replaced my original standing rigging and now don’t worry about that aspect of my boat anymore.

I'll wait and see how the pilot holes go, but I can definitely see doing the G-10 replacement at some point before doing any heavy duty long-term cruising in this boat. Do you happen to have photos of what yours look like now?

Thanks again, everyone, for your posts.

[Jim Walsh]

If you are interested in a rust converter try POR15 Stop Rust Kit for small projects 40909.

[csoule13]

The guy who did the survey on my 27 suggested Ospho http://www.ospho.com/directions.htm. Haven't gotten around to it, so can't say how it goes from first hand experience.

[ghockaday]

We have a 30 and I decided to leave them alone. They look bad but are solid. I have no leaks. If they were in a better place to get to I would change them out just for looks but getting the old ones out is a major job. Involving removed 40 year old cabinets and such. Dennis

[ghockaday]

JD-MDR That is some fantastic up-side-down fiberglass work. Dennis

[JD-MDR]

I paid the yard Big Bucks. I had the bow and main done in San Francisco and finished the backstays and mizzen ones last year here in Ventura. I like ventura's work better

[ghockaday]

I paid the yard Big Bucks. I had the bow and main done in San Francisco and finished the backstays and mizzen ones last year here in Ventura. I like ventura's work better

I would have been covered in epoxy.

[JD-MDR]

Yes.. and I am getting too old to get so contorted and I don't want all that gooey nasty resin all over.. I have to work two or more hours for every hour I pay them but It's worth it. I have no wife or kids or home and It's all going to charity when I die so It doesn't matter any more how much I spend. Basically I'm spending all I make. Now I'm almost done so I'm putting up savings for the trip , March 2022.