CD33 chainplate bolt specs?

[dolce]

Does anyone know the specs on the bolts, especially the length, of the bolts which secure the chainplate padeyes on the shrouds of the CD33. I'm hoping to order replacements while I am back in the USA but was not able to remove one for testing. It looks like the lowers are 1/2in SS flat head and the uppers appear smaller, but I have no idea what length to order.

[Jim Walsh]

I would advise waiting until you can expose the bolts from the interior as they are probably all one length to speed the production process. You may find that there is an optimal length to ease your replacement process.
Additionally, the CD33 was available as a sloop or cutter rigged. If yours is a sloop the sizes of your uppers and lowers should be the same. If you have a cutter the after lower would be smaller than the rest.
With the cost of quality flat head machine screws you don’t want any errors.

[Sterling]

Coincidentally I am changing out all of my standing rigging and just pulled all of the bolts and chainplates from starboard side of my CD33 yesterday. Still have to pull the port side. I have '81 CD33 Hull #42 sloop rigged.

2 bolts for each of the lower shroud chainplates are 1/2" x 3" SS flat head. Having said that one of the bolts for the aft lower chainplate was 3 1/2" long but I have no idea why as it appears that a 3" bolt would work just fine. All of these bolts, except for the 3 1/2" one, were partially threaded. The one longer bolt was fully threaded. Again have no idea why one bolt is different from the others.

4 bolts for the upper shroud chainplates are indeed smaller - these appear to be 3/8" x 3" bolts. The upper shroud bolts were fully threaded.

[Neil Gordon]

Most likely because they were one short of all the same when they reached into the bin... or because an odd one was placed there by mistake. Or perhaps the odd one is a post-production replacement.

[John Stone]

On the Far Reach—CD 36, Hull 61—they are longer by 1/2” on one side of the boat. That’s because when they installed the chanplate steel web it sits lower on the hull on one side. The boats are not perfectly symmetrical since they were hand built. Be cautious about assuming the bolts on one side will fit on the other. Maybe they will on one boat but not on another.

[dolce]

Thanks to all those who responded. After further research I've decided that I still need further research, thus the slow response to thank those that responded.

Each of my bolts has 1/2 inch or more threads exposed below the nut, so maybe all mine are 3-1/2", or I just have plenty of room for 3" bolts.

According to the web sources I've checked it seems that only fully threaded bolts are available in these sizes. I was hoping to get partly threaded but may have to settle.

I hope to go talk directly with a salesman at a distributor soon to learn more.

I will be doing some work this spring or summer on the weldment under the chainplates and was hoping to replace the bolts at the same time. The boat is in Mexico and I am currently in the USA gathering supplies. I could just buy some 3' bolts and hope they are long enough, or complete my project and replace the bolts at a later time. These are the perils of cruising in Mexico!

[John Stone]

Well, maybe this will be ofnuse...a cut and paste about chainplate bolts from my rebuild website http://www.farreachvoyages.com.:


One of the things on the project list was to reinstall the chain plates. Interestingly enough the most challenging aspects of the project was to find the right fasteners. The chain plates are manganese bronze from Spartan Marine Hardware. All but two are original to the boat. The original fasteners were SS and though they seemed to be in pretty good shape it seemed prudent to replace them. I thought about replacing them with bronze but unable to find domestic made bronze that did not require taking out a loan I decided to replace them with 316 SS. Though 316 is slightly less strong then 304 I wanted the extra corrosion resistance. After contacting many manufactures, starting about six months ago, I learned that it is very difficult to get any one to certify that their bolts (Jamestown Distributors, McMaster-Carr, McFeelys, Bolt Depot, etc) are made in the US. They would say it, but would not put it in writing which to me, call me silly, means they are not made in the US. OK, but where are they made? B &S Bolts in Norfolk sells lots of milspec and ISO 9000 certified fasteners but not in what I was looking for--flathead, 316, 3/8" and 1/2", etc. But they would certify they were made in Sweden, Canada, Belgium, etc. And, they would put it in writing. That was the best I seem to be able to do. Once I had the bolts it was pretty simple to install them. Once again I decided to bed the hardware with butyl rubber. Check another project off the list.

[Jim Walsh]

Each of my bolts has 1/2 inch or more threads exposed below the nut, so maybe all mine are 3-1/2", or I just have plenty of room for 3" bolts.

According to the web sources I've checked it seems that only fully threaded bolts are available in these sizes. I was hoping to get partly threaded but may have to settle.

https://www.mcmaster.com/91781a726

These are partly threaded, passivated, 18-8 stainless. I went with 316 for my pedestal bolts because they are in a high visibility application. I doubt I’d go for 316 for chainplate bolts. We all get to decide what suits us.

[dolce]

Well, the 3" bolts I bought would have worked just fine, except that I added 1/4" G-10 to the mix, which made the 3" bolts about 1'8" to short. Read about that on our blog.

The nylock part of the nut was not engaging. I did not think about the extra 1/4" when i ordered, so I had to put the old bolts back in for now. Luckily they look to be in good shape.

If you can use 3" bolts, see my post: http://www.capedory.org/board/viewtopic.php?f=4&t=36570