USS United States (CVA-58) in the context of "Keel"

The keel is the bottom-most longitudinal structural element of a watercraft, important for stability. On some sailboats, it may have a hydrodynamic and counterbalancing purpose as well. The laying of the keel is often the initial step in constructing a ship. In the British and American shipbuilding traditions, this event marks the beginning date of a ship's construction.