In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel's the initial step in construction of a ship, the construction's dated from this event, with only the ship's launching considered more significant in its creation. Structural keels A structural keel's a large beam around which the hull of a ship's built. The keel runs in the middle of the ship, from the bow to the stern, and serves as th… (More on Keel)