Thanks, Ronald. I had thought about leaving the threads out as you mentioned, but from my research the problem with that is that it will interfere with the lower rudder casting on the H16, preventing full steerage.

There is a part of me that is thinking about removing the entire transom down the the innermost glass. Basically bringing it back to a flat surface. That would give me about 1/2 in. or more of the hull sides glass. I could then glue the plate in. I could lay glass over that and have the whole inside glass to laminate it to. I would then fair all of that down flat again. Then, glue in new plywood to match the shape of the entire transom. I would also glue it to the sides of the hull. Then I could lay fiberglass over the entire new plywood and interior sides of the hulls and build everything up again. It seems to me that this would be the strongest repair, and probably bring everything back to a more original state. It would give me the most surface area for new glass/epoxy puttty. Again, if my thinking is wrong here don't hesitate to let me know.

I am planning to install the one-piece gudgeons.

Is this kind of what your were saying, Ronald? I definitely want to make this a strong repair.