: Why are bulkheads not appropriate?

: Bill H.

I'm sure you know Bill my solution is the closed cell blue build building foam first used by the Coast Guard and US Navy in rafts and boats in WW2. The problem is you have to fit these in the bow and stern before the deck is attached to the hull. They are held in by the shaped press fit and a mechanical lock but can be take our by way of the forward and aft hatches.

John