A boat is a watercraft of modest size designed to float or plane, to provide passage across water. Usually this water will be 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 something small enough to be carried aboard another vessel (a ship). Strictly speaking and uniquely a submarine is a boat as defined by the Royal Navy. Some boats too large for the naval definition include the Great Lakes freighter, riverboat, narrowboat and ferryboat.