Here is another place where I decided not to use heavy woods. I had some nice balsa core material from a multihull sailboat project. So I cut it out to the correct shape to use as the primary bulkhead in the center of the boat.
In this picture I am sealing all the open edges with epoxy. Next I sanded off the old paint to get it ready to fillet into the boat. The balsa core bulkhead woorked pretty good. It was not as stiff as the wood bulkhead may have been.