You may not have seen this but here is the answer that I gave you last time you asked this question:
Even a badly damaged bulkhead will often be holding a boat in shape. It is important that before you remove the existing bulkhead you take all loads off of the hull and deck in this area. That means unstepping the mast and carefully placing the jackstands so that the hull won''t get distorted.
Before you remove the bulkhead, you should take careful measurements and make a cardboard or plywood template that you can later use to check that there hasn''t been distortion of the hull and deck.
Many times bulkheads are installed before the decks are put on and so in some boats you cannot install a replacement bulkhead in the finished boat. In those applications you may need to build the bulkhead in pieces. The technique that I have used in that situation is to build the bulkhead in several pieces. Bacically I made two bulkheads each half of the thickness of the finished bulkhead(in my case two layers 1/4" thick). Each lamination of the bulkhead was cut horizontally so that the bottom could be put in place and the top sprung back in above it. The horizontal joints were staggered roughly a foot. The process consisted of sliding the taller of the two lower half bulkheads into place, buttering up the shorter bottom bulkhead half with slow cure epoxy
and sliding it in place. Buttering up the longer half of the upper bulkhead and putting it in place and then installing the shorter upper bulkhead. They were clamped with small sheet metal screws that were later removed and the holes patched.
All sides of the bulkhead were sealed with multiple coats of epoxy
before assembly and strips of rubber were used as a spacer between the new bulkhead and the hull. When cured the new bulkhead was tabbed in.
Marine surveyor firends tell me that this issue of rotted bulkheads is becoming ''the next blister problem of the 21st century'', meaning that it is becoming extremely common to find older boats with plastic laminate (formica) on their bulkheads masking serious rot. Once rot begins behind plastic laminate it is free to spread un-noticed until the bulkhead is shot. The plastic laminate actually contributes to the rot by not allowing the bulkhead to dry out as quickly when it does get wet.