Cape Dory 30-36 Chainplates

[Patches]

In considering a Cape Dory for a cruising boat, I’ve read about the factory method for attaching chainplates/standing rigging. Can anyone confirm that the method of glassing in the mild steel chainplates was the same on all Cape Dory 30-36 foot models?

Also, does anyone know if Robinhood continued this construction method on the 36?

Many thanks,

Patches

[Jim Walsh]

In considering a Cape Dory for a cruising boat, I’ve read about the factory method for attaching chainplates/standing rigging. Can anyone confirm that the method of glassing in the mild steel chainplates was the same on all Cape Dory 30-36 foot models?

Also, does anyone know if Robinhood continued this construction method on the 36?

Many thanks,

Patches

I can confirm that my CD31 does not have “glassed in” mild steel chainplates. It has Spartan bronze chainplates on deck with aluminum backing plates below deck (attached with SS flat head machine screws, washers, and nuts). They are accessible for inspection, which I do prior to any offshore passages. I don’t know if this was the method used on every CD31. I know other models do have mild steel chainplates so hopefully owners of those models will chime in.

[gonesail]

the 30 mkII chainplates are also bronze on deck .. thru bolted to ss rods anchored to structural hardware.

[Patches]

Thanks. I’m aware the stays go to bronze “chainplates” at the deck. Through review of other posts on the forum, my understanding was that those bronze chainplates are then bolted through the deck and then the loads are distributed from there to the hull through a steel “T” or “Y” glassed into hull.

From gonesail’s response below, it sounds like the 30 Mark II has a kind of “tie rod” structural system below deck similar to similar vintage Ericsons. Am I understanding that right?

And from Jim’s response, the Cape Dory 31 transfers the load at the chainplates to an aluminum backing plate (I assume under the hull/deck joint?).

From the early responses, looks like several different methods for transferring the loads from the bronze chainplates to the hull were employed.

Patches

[gonesail]

yes the 30 is tied into a steel structure but it is not glassed into the hull. it is behind the settee and has no corrosion problems.

[Jim Walsh]

Thanks. I’m aware the stays go to bronze “chainplates” at the deck. Through review of other posts on the forum, my understanding was that those bronze chainplates are then bolted through the deck and then the loads are distributed from there to the hull through a steel “T” or “Y” glassed into hull.

From gonesail’s response below, it sounds like the 30 Mark II has a kind of “tie rod” structural system below deck similar to similar vintage Ericsons. Am I understanding that right?

And from Jim’s response, the Cape Dory 31 transfers the load at the chainplates to an aluminum backing plate (I assume under the hull/deck joint?).

From the early responses, looks like several different methods for transferring the loads from the bronze chainplates to the hull were employed.

Patches

The CD31 chainplate details can be seen in the attached graphic from the Owners Manual.

IMG_0474.png

[Carl Thunberg]

I think a lot depends on the year of manufacture. My former CD30 had mild steel backing plates. After 40 years, they were still fine, because I and the former owner re-bedded stanchions and deck hardware regularly.

[Frenchy]

As a side note, I would say don't reject a boat just because it has mild steel under the deck. My boat, a 33, has been in salt water
for all its life and there is no corrosion. It depends on the vigilance of previous owners. The system is actually very good
because the upper bronze chainplate fitting, properly bedded, keeps water out. Other boats most often feature a flat chainplate bar penetrating
the deck, leading to rotten bulkheads and corroded, oxygen-starved stainless.
So anyway, yes, it is a concern and needs inispection before purchase. In my boat, you can inspect that steel with a mirror
in the head locker port side and in the clothes locker to starboard - Also, in the main salon under the side decks.

[sanderling]

My CD33 hull #8 has the mild steel "weldment". Like Frenchy's comment, mine are in good shape with only some surface rust.

weldment.png

For the rust to reach the lower portions parts of the weldment that are glassed in to the hull, my opinion is there would have to be signs of water intrusion or corrosion at the 46" flat (backing) portion. On my boat you can see the ghost image of those lower glassed in parts of the weldment on the exterior gelcoat. My opinion is that as Cape Dory used this type of system the workers used varying degrees of thickness (and quality) in this area as time went on.

chainplates.png

But I believe I have seen posts somewhere regarding an owner who did have issues and dug out the lower glassed in steel and replaced with G10.

[John Stone]

My CD36 Far Reach is hull #61. She was built in 1982. I have the steel backing plates. I completely gutted my boat to a bare hull. I inspected them closely. They are in excellent like new condition so I left them in place. The bowsprit backing did have rust. It was an hassle to remove it but I got it out. Even though it had rust as I examined it I realized it was still more than up to the job. However I replaced it with 1/2" G10 because I designed and built a different kind of bowsprit so I did not need the steel. Around hull #66 they switched from steel to aluminum backing plates. This would be in late 1982-1983.

[Patches]

Thanks for all for your replies. What sparked my questions was my interest in the CD 330. In the owner manual for that model, there is mention of the “metal weldment” as part of the chainplate structure. Sanderling’s reply was particularly helpful in illustrating the structure below deck. That metal weldment seems like a standard construction practice across the Cape Dory line-up.

Although his boat is a CD 33, and earlier than the 330, the 330 Owner Manual description of the “metal weldment” leads me to conclude that the mild steel reinforcement below deck remained the same during the transition to the 330. I am surprised at this construction detail, as well as the use of mild steel to support and back the stem head.

Sounds like the (now) 35+ year condition of these “metal weldments” can vary greatly in used Cape Dories. But assessment of the mild steel structure looks to require some deconstruction of the interior at those locations. If compromised, proper replacement/upgrade with G10 appears to be a real project. I suppose one could also go to external chainplates at that point (Sam Holmes), but not sure how I would like looking at those.

Again, thanks for your helpful replies!

Patches

[John Stone]

Well, I initially thought the steel weldment was a bad idea. But after gutting and rebuilding my boat and sailing it many offshore miles I have a different perspective. Steel is strong. True, it will rust if it gets wet especially with saltwater. But think about it. Ships are made of steel. It's not expensive to fabricate. It is easy to weld. Also, steel has little to no potential for galvanic reaction to SS or bronze bolts.

The key is to prevent water from getting into the interior through the pad eye and hull deck joint. I know of few if any CD owners who have removed the pad eyes and rebedded them with something like butyl rubber. Most of these boats are 40 years old and subject to horrible conditions like blazing sun and freezing temps. Most owners do minimal maintenance. We would never expect a house to last under the conditions boat experience and do practically no major maintenance. I only know of a couple of owners who when they noticed water getting into their boat's interior through the hull deck joint took corrective action by removing and glassing over or at least recaulking the joint and reinstalling the toe rail. They just look the other way.

Boats are not a fiscal investment. They are life investments. You have to spend time and money on them if you want them to perform to their maximum potential.

Regarding the phrase "metal." Aluminum is metal. It could be the 330 has aluminum. While replacing/repairing the weldment is not simple it is doable by a committed owner with the boat in the water.

(Edited for spelling)

[Steve Laume]

I believe Cape Dory switched over to aluminum for the backing plates for the rigging, pad eyes in 1984.
Raven's hull was laid up in late 1983 but she is a 1984 model with aluminum backing plates.