Good day. I want to apologize in advance if my terminology is wrong or I don't completely understand what is being said because I am just a self-taught sailor. I recently purchased a 1985 Catalina 27 that is in a slip on the lake with the mast stepped. I recently noticed that the port side bulkhead has some rotting at the top and the veneer is peelings badly. I would like to completely remove and replace this piece but not sure if that is a job for an average guy. I figured I would remove the chain plate, dismantle the little locker the bulkhead make ups, and use the old as a temple for a new bulkhead. I would use a new piece of marine grade plywood. Has anyone done this before and can offer advice? How would I support the mast with the upper shroud removed? I have attached the only picture I currently have that shows the area. Thank you for the help.