Hokey? Nah!
I can easily picture him setting up a small workshop somewhere down in the dungeon. There, under a beam of pale moonlight coming from a hole in the roof, he would carve out oars from one piece of wood, cut logs into planks, plane them, and then nail them together. He would then have to tar his vessel to make it watertight and perhaps add a few features for comfort, such as a seat and a storage space with a hatch. Easy.
