A maritime pilot, also known as a marine pilot or harbor pilot and sometimes simply called a pilot, is a sailor who manoeuvres ships through dangerous or congested waters, such as harbors or river mouths. He is normally an ex ship captain and a highly experienced shiphandler who possess detailed knowledge of the particular waterway, e.g. actual depth, direction and strength of the wind, current and tide at any time of the day.
Maneuvering a ship through the shallow water to berth / unberth in a port requires teamwork which involves, apart from the port pilot, the ship's captain (jointly responsible), ship's crew, port tugs, and shore linesmen. Since the pilot is on board the ship, he controls the tugs and linesmen through a radio and the ship directly. The ship's captain ensures his crew carry out the pilot's orders.
High skill is required to be a pilot as the channels through which the ships move towards the port is normally too narrow and shallow for the size of the ships, stopping distance of the ships being a few nautical miles and the fact that ships do not steer at slow speed. Even if a ship captain is a regular visitor to a certain port, he can not match the expertise and experience of the Pilot.
In an unfortunate case of an accident, high pollution is a risk as the ships carry thousands of tonnes of fuel for her own consumption.(Clean up cost and other damages of the Exxon Valdez disaster was around $ 5 billion). Also if a ship is wrecked in the channel, the channel and the port could be closed for months till the shipwreck is removed.
Most ports have compulsory pilotage.
Legally, the master has full responsibility for safe navigation of his vessel, even if a pilot is on board. If he has clear grounds that the pilot may jeopardize the safety of navigation, he can relieve him from his duties and ask for another pilot or, if not compulsory to have a pilot on board, navigate the vessel without one. Only in transit of the Panama Canal and in Canada does the pilot have the full responsibility for the navigation of the vessel.
In English law, Section 742 of the Merchant Shipping Act 1894 defines a pilot as "any person not belonging to a ship who has the conduct thereof." In other words, someone other than a member of the crew who has control over the speed, direction, and movement of the ship. The current United Kingdom legislation governing pilotage is the Pilotage Act 1987.