That's not a chain-plate... THIS is a chain-plate.

I have started working on the lower saloon. I made a new headliner over the port side settee while I was repainting the headliners from the aft cabin, and of course once you start...

I stripped out one of the port side lockers which we had lined temporarily in California... Four years counts as temporary, doesn't it? I'm going to line it properly, but while I am at it I thought y'all might be interested in seeing what a real chain-plate looks like.

For a sense of scale, those bolts are 5/8" and the cupboard is about 1m wide. The chain-plate proper comes down and is bolted into a fabricated box section that has flanges at the back which are in turn bolted into the hull and through a bronze backer plate. The backer plate runs fore and aft under the ribs, and is a full length run between the lower stay chain-plates, a distance of about 1.6m. This backer plate is itself fastened into the hull along it's length (the columns of small fasteners you can see).

Certainly a different class of engineering from the little bits of stainless that count as chain-plates on a modern production boat.