Barrett Faneuf was all fancy with her transom, and used a saw to cut the planks edgewise into thin slices. I have no saw. What I do have (thanks Dai!) is a thumping big router with a 25mm bit, a huge hand plane, and a whole lot of
After a couple of days of going at it with the router, I had a really rough surface approximately 6mm thick, which I could then plane smooth. This I did with my awesome English Stanley no. 7, the smootherator.
Putting the doubler on the transom gave me another opportunity to use all my clamps at once.