Bryon:
If you have to replace the crushed wood - please take photos of the project as I'd like to make them available for others on this site.
Mike:
One of the fixes that Bud suggests and that I've installed - are 4-5 bronze nuts/bolts installed through the deck beam. Two of which can be seen in the attached image.
My understanding is that the bolts are supposed to tie the beam and the bulkhead together ie spread the load from the deck beam to the bulkhead.
This suggests that the bulkhead isn't secured originally to the bottom of the cabin nor the beam. There may be an air gap between the top of the bulkhead and the bottom of the cabin top hidden inside the deck beam.
On Pygmalion the deck beam is made out of multi pieces of mahogany and ash? that surround the bulkhead but were not actually secured to the bulkhead before I added the bolts.
In Bryon's case, the mahogany has been crushed - I think we will know the cause later assuming he works on the area.
A disclaimer is that I have NOT actually disassembled the desk beam and so I can only guess from what I see on Pygmalion.
Also I would not be surprised if other boats are different in this area as construction did change over time.
Jacking up the deck/beam - Yes the jack will need to be supported carefully to spread the load on the cabin floor and desk beam or there will be issues... also the standing rigging will need to loosened to allow movement.
I'm told that the bottom of the beams are supposed to be on the same plain... sight along the bottom or use a tight string to see if the beam under the mast has moved.
HTH
Jay