Aft bench

I always wondered from the original drawing, how it was possible to install the aft bench. There is a filet inside, but no real access...

After thinking probably too much about it, we decided to glue pieces of wood along the 4 sides (hull stbd and port, transom and frame C). The bench; once cut will come and rest on these support at the right place. We will then filet the external side of the bench and put some fiberglass to reinforce everything.