One difference as I have aged is I don't mind cutting holes in my boat. I wouldn't have even contemplated such an undertaking as a young'n.
Last fall I was trying to figure out why I had paint cracking on the aft deck of my Maser. The aft deck seemed very soft. Three mm. plywood is flexible but this seemed worse than usual. The only way I was going to find out was to cut two holes in the aft deck. It turned out that there was a mini-frame, about 50 mm. deep, of 3 mm. plywood, set aft about 300 mm. from the main aft bulkhead. It had cracked on both sides about 150 mm. in from gunwhales, probably when I had moved aft on that area on a heavy-air reach.
To make the frame whole again, I sistered the frame at both the cracks.
The following photos show the process of working backwards to get a watertight aft deck once the repairs had been made.
Backing pieces glued on. Plywood top piece cut to fit. I used a top piece of pine as a gluer for the plywood top piece on the aft side. This also gave some added I-beam strength above the mini-frame. (I cut the hole right next to the mini-frame repair and didn't have room for an aft backer strip.)
Close up of the open hole with backers in place.
Both plywood pieces in place, glued up. Top aft I-beam pine piece glued down.
Repairs glassed over with 9 oz biaxial cloth.
I was eventually able to get some primer down and that is how she looks at the present time. Good enough for a Tweezerman repair.
Click here for the original Maser post.