A maritime pilot, marine pilot, harbor pilot, port pilot, ship pilot, or simply pilot, is a mariner who maneuvers ships through dangerous or congested waters, such as harbors or river mouths. Maritime pilots are regarded as skilled professionals in navigation as they are required to know immense details of waterways such as depth, currents, and hazards, as well as displaying expertise in handling ships of all types and size. Obtaining the title 'maritime pilot' requires being an expert ship handler licensed or authorised by a recognised pilotage authority.