Pilots with local knowledge have been employed on board ships for centuries to guide vessels into or out of port safely - or wherever navigation may be considered hazardous, particularly when a shipmaster is unfamiliar with the area. In addition to local knowledge and expertise, pilots are able to provide effective communication with the shore and with tugs, often in the local language. Qualified pilots are usually employed by the local port or maritime administration and provide their services to ships for a fee, calculated in relation to the ship's tonnage, draught or other criteria.

The importance of employing qualified pilots in approaches to ports and other areas where specialized local knowledge is required was formally recognized by IMO in 1968 when the Organization adopted Assembly resolution A.159(ES.IV) Recommendation on Pilotage. The resolution recommends Governments organize pilotage services where they would be likely to prove more effective than other measures and to define the ships and classes of ships for which employment of a pilot would be mandatory.

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