Pilotage
Pilotage is the service by which a marine pilot — an expert in a port's local waters — boards a ship to guide (con) it safely into, out of, or within a harbour, channel or river. The pilot brings intimate knowledge of the depths, currents, tides, traffic and hazards that a visiting ship's crew cannot have, advising the master on navigation and ship-handling through confined and busy waters.
Pilotage is compulsory in most ports for ships above a certain size, for safety and to protect the port and environment. The pilot boards from a pilot boat (or by helicopter) at the pilot station, typically works alongside tugs for berthing, and the master retains overall command. Pilotage dues are a standard part of a port call's cost. Efficient pilotage keeps ship movements safe and the port's traffic flowing, and is coordinated with vessel traffic services and towage.
No visiting master knows a port's shifting channels, currents and traffic like a local pilot — which is why pilotage is compulsory and central to port safety. It keeps big ships from grounding or colliding in confined waters, works hand-in-hand with tugs and VTS, and is a standard line in every port-call cost.
Is pilotage compulsory?
In most ports it is compulsory for ships above a set size, for navigational safety and to protect the port.
Does the pilot take command of the ship?
No — the pilot advises and cons the ship with local expertise, but the master retains overall command.