A boat is a watercraft of any size designed to float or plane, to work or travel on water. Small boats are typically found on inland (lakes) or in protected coastal areas. However, boats such as the whaleboat were designed for operation from a ship in an offshore environment. In naval terms, a boat is a vessel small enough to be carried aboard another vessel (a ship). Another less restrictive definition is a vessel that can be lifted out of the water. Some definitions do not make a distinction in size, as bulk freighters 1,000 feet (300 m) long on the Great Lakes are called oreboats. For reasons of naval tradition, submarines are usually referred to as 'boats' rather than 'ships', regardless of their size and shape.
A ship is a large buoyant watercraft. Ships are generally distinguished from boats based on size, shape and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing, entertainment, public safety, and warfare. Historically, a "ship" was a sailing vessel with at least three square-rigged masts and a full bowsprit. Ships were always a key in history's great explorations and scientific and technological development. Navigators such as Zheng He spread such inventions as the compass and gunpowder. Ships have been used for such purposes as colonization and the slave trade, and have served scientific, cultural, and humanitarian needs. After the 16th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to the world population growth. Ship transport has shaped the world's economy into today's energy-intensive pattern. -wikipedia