A boat is a watercraft of any size designed to float or plane, to work or travel on water. For small boats, this is typically inland (lakes) or in protected coastal areas. However, boats such as the whaleboat were designed to be operated 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 1000-foot bulk freighters on the Great Lakes are called oreboats. For reasons of naval tradition, submarines are usually referred to as "boats" rather than as "ships", regardless of their size. Boats come in a wide variety of shapes, sizes and construction due to intended purpose, available materials and local traditions. Canoe type boats have a long history and various versions are used throughout the world for transportation, fishing or sport. Fishing boats vary widely in style partly to match local conditions. Pleasure boats represent a less practical approach, including ski boats, pontoon boats , and sailboats. House boats may be a vacation or provide long-term housing. Small boats also provide transport or move cargo (lightering) from large ships. Lifeboats are an important safety measure.