Chainplate knee glassing

[Ryan]

While in the process of stripping my old bucket, uh boat, for restoring, I noticed that the chainplate knees seem to be nothing more than a piece of wood (no doubt rotten like every other piece of wood) with one or two pieces of glass over it. Since the chainplate, bolts and backing plate are all under the glass, I'll have to cut it all apart to inspect. Do you guys have any suggestions on what type of cloth/roving to use when the time comes to glass the new knees back in place? Thanks.

[Robert The Gray]

Ryan,
great to have you here.Sorry but I do not know how to answer your question, but I just tried the search function on this forum and typed in "knees". I got a bunch of hits. Try this next time and you might get your answer really quick.

Robert

[Tim]

That sounds like a terrible mess. You're definitely best off ripping it all out.

Use some more of that good biax to glass in your new structural member, with several wide overlapping layers extending well onto the hull and over the structural member. Encapsulate any wood completely, and install your chainplates and bolts external to the glass--that is, after the glasswork is done. That way, future inspection and maintenance will be easier.

[Ryan]

With the aforementioned chainplates out, I am getting ready to replace them and the structural members that they mount to. I am planning on using two pieces of red oak 1"x3" epoxied together to give me a 2"x3" piece of oak that will then be glassed to the hull. Do you guys/girls see any problem laminating the two 1" pieces together? Would you recommend that I put some sort of foam pad between the oak and the hull itself? Thanks in advance.

[Noah]

Red Oak is pretty rot prone, much more so than white oak. It has to do with the cell structure. You can blow bubbles through a 2ft piece os red oak....I would use white if I were you.

[CharlieJ]

Red oak is NOT a good choice. A better choice would be some mahogany or even some lams of thinner plywood.

[Ryan]

Thanks for the warnings. I'll use white oak instead.

[bcooke]

When I replaced my chainplate knees I used some high grade marine plywood I had left from another project but would red oak be all that bad if it were encapsulated in epoxy first?

No matter what wood I was using I would clear coat the whole piece with epoxy before I glued it in and layed the cloth over it anyway so I wouldn't have thought the open cell structure of red oak would make much difference.

-Britton

[Noah]

After I wrote that about white oak I realized that it can have a tough time with epoxy...People have said that they have had problems with epoxy sticking to white oak, presumably because of the tannins in the wood. Wiping down with Acetone before is said to help. In this case some marine ply might not be a bad choice.

Red Oak would probably hold up oak, but chainplates are notorious for leaking. If it's going to be leaking right onto the oak you will be in trouble.

[Ryan]

Since the original chainplate replacement turned into a full on gut job, I am just getting back to rebuilding the chainplate knees. Is there any type of consensus as to what the best material is for the "core" of chainplate knees? It seems that red and white oak have issues (as I suspect everything does if we look hard enough), is there something more preferable?

[Tim]

There's no reason not to use quality plywood (void-free, such as meranti). Just be sure that it is well sealed against moisture (which applies to anything, of course).

[tigerregis]

My boat, though factory was built at home. The builder was an elevator installer, so everything he did was overbuilt. His go at the knees was laminated white oak stock. In the middle of Lake Ontario the glue(?) sheared and the chainplate pulled up about 3/8". A friend cut them out and used solid white oak to replace them. They were bonded as Tim recommended above. That was 15 years ago and they are still looking good.

[Duncan]

This is an issue I've been thinking about since I bought my 1966 Paceship Eastwind last summer. The attachments for the fore and aft shroud chainplates are completely encapsulated in glass, so I have no idea what condition things are in. I don't think it would be smart to just hope for the best.
This thread will help me put it all back together once I grind off the old and take a look, thanks.