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. They are navigational experts possessing knowledge of the particular waterway such as its depth, currents, and hazards, as well as being experts in handling ships of all types and size. A Maritime pilot is an expert ship handler who is licensed or authorised by a recognised pilotage authority.
https://en.wikipedia.org/wiki/Maritime_pilot
https://fi.wikipedia.org/wiki/Harmajan_majakka