Whereas in terms of naval terms, boats are boats small enough to carry on board other ships (aircraft carriers). In another definition the boat is a ship that can be lifted out of the water. Some definitions do not make a difference in size, as mass transit is 1,000 feet in the Great Lakes called oreboats. For reasons of naval tradition, submarines are usually referred to as 'boats' rather than 'boats', regardless of the size of the ship or boat in intention.
