repairing the stern

We've spent today fitting two new planks to the transom (the flat bit at the back of the boat) Dad had cleared away the old timber over the last few weeks.
This morning we removed the rudder guard, and the thick aluminium plate which had been fitted to cover up the horrors that lay beneath. I came very close to going swimming as I balanced the heavy metalwork on the dinghy and floated it over to the pontoon.
In the photo I'm checking the fit of the first plank, the transom is made up of two layers, each 2 1/2 inches thick!