Courtesy Israel Dept. of Antiquities and Museums/Photo: Shelley Wachsmann

When telltale signs of mortise-and-tenon joints appeared, the excavators knew they had found an ancient boat. Two round-headed wooden nails, right and left of center, peek out of a small section of the uppermost plank. In antiquity, Mediterranean shipbuilders devised the mortise-and tenon method of joining the hull planks to one another (see drawing).