Are fiberglass knees generally attached to the deck?

[nelly]

I am doing some recoring work, and rebedding the chainplates on my 1980 Hunter.

I realized that after taking everything apart, the knees (is this the correct term? - what the chainplates are attached to) are actually not attached at all to the underside of the deck. There is gap at the top of the knee - like a good gap. Over 1/4" for at least a couple of them.

This seems super odd to me but I guess kind of makes sense if I am thinking about how the boats are built (deck dropped on and bolted onto the boat).

Is this pretty usual? Should I do anything while I'm doing work here? Could probably put a spacer of fiberglass board in there without a ton of thought... would be harder to really glass something in though.

I do know the knees pull up very slightly when the rig is tuned - I know this because they pull away a little from the shelf under them (the shelf isn't properly supported by the knee, separate issue I have to fix).

As far as I can tell the knees are sound structurally. No delamination in them whatsoever.

Here is a pic: https://i.imgur.com/arFU9bX.jpeg

The crack on the bottom is the fiberglass separating from the shelf. This will be fixed soon anyway.

[Jammer]

Originally Posted by odonnellryan

I realized that after taking everything apart, the knees (is this the correct term? - what the chainplates are attached to) are actually not attached at all to the underside of the deck. There is gap at the top of the knee - like a good gap. Over 1/4" for at least a couple of them.

I would call it a bulkhead.


The bulkhead won't really flex as such from the shroud load. But the load from the shroud will pull the sides of the hull inward so that the bulkhead moves up somewhat. For this reason it probably wasn't attached to the deck, by design, as the deck would not be able to resist this force in a useful way. On my Hunter H26, the companionway would narrow by 1/8" or so when the boat was in the water and the mast was stepped, as a result of these forces.

[thomm225]

All 6 fiberglass knees on my boat a Bristol 27 are as you describe and are not touching the deck.

[nelly]

Good to know, thanks all!