Chain plate knees on the Bolero Project . . .

[Ancient Race]

Tim -

I've been anxiously following the chain plate knee project on Bolero, with an interest in what type of foam you'd use to isolate the knees from the hull and deck, thereby avoiding hard spots.

My interest derives from being in the midst of the same project on the Tartan, and engaging in an internal foam/no-foam debate myself.

I'm posting here in questions rather than projects because I'm interested in the reasons you chose to butt the knees directly to the hull and deck. (The pics are just so Rachel won't have to ask . . . I'll include a full documentary in projects as it progresses.)

As you can see, the Tartan rig has uppers and lowers, no jumpers. Both chainplates are mounted on a single knee on each side of the hull, separated by the width of what appears to be 3/4 ply. The entire unit is encased in a thick layer of glass and resin. (Why it was standard practice to compromise the stainless attributes of stainless steel by closing it off from oxygen in an environment that was bound to admit water is another thread.)

Here's the starboard side knee, with the aft fiberglass removed:



And this is what it looks like port:

[Rachel]

The pics are just so Rachel won't have to ask . . .

Oh suuUUuure, single me out. :pouts:

Oh well, it worked. We got photos. Thanks!

People put stainless in some crazy places, don't they?

Rachel

[Tim]

I'm interested in the reasons you chose to butt the knees directly to the hull and deck

I think the formation (or not) of hard spots at structural locations is more complex than just whether or not there's an isolation between the member and the hull. Foam is all well and good, and makes sense in many cases, but I don't see it as necessarily a universal need.

For something like a larger transverse structural bulkhead, where the hull will tend to "bend" around that spot, I think a potential hard spot is much more likely. For these relatively small chainplate knees, with their loading distributed between hull and deck and in an area where this sort of panel bending is less likely, I just didn't see a call for foam.

[Ceasar Choppy]

Its been my experience with chainplate knees that the "hard spots" usually come in the form of dimples on either side of the knee, not at the knee itself. I think your tabbing and what you can do to spread the load across a larger area would be more important.