The term 'Parts of Hulls' refers to the components of a ship's hull, which is the outermost layer of the ship. The most common part of a hull is the keel, which is a long beam that runs along the bottom of the ship and provides stability. It also serves as a base for the other parts of the hull, such as the frames and plating. The keel is an essential part of a ship's hull and is necessary for its structural integrity.