Ships

A ship is a watercraft used for the transport of cargo or passengers. Though “ship” originally referred to a sail-driven craft with a particular type of rigging, today it refers to any large watercraft. The difference between a ship and a boat is simply one of size, although there are some exceptions—riverboats, ferryboats, and submarines are considered boats regardless of size.

Ships are referred to in the female gender in the maritime trade, in casual use, and in some formal style guides. Ships usually have individual names, and, despite the convention of a ship being female, the name may be female, gender-neutral, or male (e.g., military ships are often named for former presidents or generals).

Ships and boats are among the oldest forms of transportation, and their uses in fishing, whaling, and transportation of goods across waterways were key to the development of human civilization. Many early settlements were founded by seafaring people from other lands, and critical historical developments have been wrought by waves of such people introducing cultural and material novelties to new lands or colonizing them.

Among the host of colonizers who arrived by ship are the Vikings of the early Middle Ages, who sailed throughout Europe and far northern North America, and the Europeans who created trade routes and colonies throughout the world from the 15th century on. Marine travel was also critical in the development of scientific understanding of the world. As the sciences of navigation and mapmaking were being refined, the compass and optics were developed in support of sailing, and ship design evolved as understanding of mechanics improved. Ship travelers all over the world introduced their cultures to new ideas, new foods, and previously unknown forms of life.

The hull of a ship is the foundation of its architecture, and buoyancy is achieved by the hull displacing a greater weight of water than the weight of the ship. Ships do not glide on the surface of the water but, rather, sit upon the water with much of the ship submerged beneath what is visible. Compartments in the hull are used to hold ballast water, providing weight that helps stabilize the ship by making it bottom-heavy.

The foremost part of the hull is the bow, while the keel extends along the length of the ship at the bottom of the hull and provides stability and longitudinal strength. In the Anglo-American shipbuilding tradition, the construction of the ship begins with laying down the keel. Propulsion systems are usually mechanical today, with sail- and human-powered propulsion generally used only for small boats. Mechanical propulsion systems usually use a diesel engine to drive one or more propellers, for which there are numerous designs. Steering is accomplished by the lateral force enacted on the water by a rotating rudder.