Alberg 30 chainplate

[David VanDenburgh]

I've got a question for the experts.



This chainplate is on the starboard side just forward of the bulkhead (currently removed) that separates the saloon from the hanging locker. The chainplate is tabbed to the hull and was also tabbed to a shelf located in the locker. I'm planning on tabbing it back to the shelf when I put things together, however, I'm wondering if I ought to do some additional work to beef it up since it looks a bit iffy to me. What is the collective wisdom of the forum?


Here's another photo of the area.

The biggest challenge is that the space is going to be very cramped once the new bulkhead goes back into place. My thought was to remove the bolts and add a couple layers of tabbing on the aft side of the chainplate, then redrill and bolt things together. Ideally, I'd like to add tabbing to both sides over the whole length of the piece, but that would throw off the alignment of the chainplate.

Thanks for your input!

David

[Figment]

I'm not quite sure of what I'm looking at. I don't see a chainplate. I see what might be a chainplate knee, but it seems strange that they would bother with a knee when a bulkhead exists 3" aft.

The actual chainplate bolts to the forward face of that knee?
That's where you need the tabbing. That's where the load hits.
Of course one could make the argument that it's been just fine as-built for however many years the boat has been around.

Tab the aft face as well, of course, but do consider trying to get something onto the forward face. I also think it's a good idea to tab it to the shelf, just for the extra bit of lateral support.

[David VanDenburgh]

Sorry for the lack of clarity. Yes, you're looking at the knee that the chainplate attaches to. The chainplate is on the forward side (left).

Thanks.

[Ceasar Choppy]

Nice pix, but because photos are so 2 dimensional, it is hard to see exactly what is going on.

How thick is the knee? Have you ground off any of the original tabbing of the knee???

You might be surprised at how much glass is holding that knee in place.

On my Pearson 39 I thought I might have to replace my knees, but it turned out that while they were cored with plywood, the plywood was only about 1/4" thick and there was 1/2" of fiberglass on both sides.

I had a different problem... I was worried about water getting into them and rotting the wood core. If you need to investigate, try what I did: take a small hole saw and drill at one of the bolt holes of one of the knees to take a core sample. DON'T DRILL ALL THE WAY THROUGH! If you can leave something on the other side of your hole. Inspect the core sample, and if satisfied, save the core sample and epoxy it back into place.

[Tim]

Do you see any evidence of rot, cracking, delamination, or other damage to that chainplate knee, internal or external?

Typically, these things are very ugly in these old boats. Ugly, however, may well be perfectly structurally sound. Lacking any real evidence of a structural shortcoming, I'd say offhand that the knee as it exists is probabably just fine to be returned to service as is.

If you want to add some more glass, a layer or two won't throw off your chainplate alignment that much--maybe 1/8", depending on the weight of the new material. You could broaden the chainplate slot in the deck a scooch if you needed to.

There's a lot of re-reinforcement going on during rebuilds of these old boats. Often, the additional material is entirely unnecessary. I can't tell enough from your photos to know for sure, but additonal material "just because" isn't a good enough reason when something's worked well for 40 years as is. Just a thought!

On the other hand, sometimes there's a clear reason to reinforce, or redo. If this is the case, it's far better to completely remove the old and build a whole new structure.