call

A call is a scheduled stop at a port where a vessel discharges cargo, takes on cargo, refuels, or embarks and disembarks passengers. For a shipping line, the call is a discrete business transaction: berth reservation, handling fees, pilotage charges, and customs clearance all cluster around this single port event. A vessel's route is built as a sequence of calls, each with its own window of time and economic justification.

The distinction between a call and a mere passing-by matters operationally. A call requires advance notice to port authorities, typically 72 hours or more depending on port rules and vessel class. It triggers invoices from stevedores, tugs, agents, and warehouse operators. A ship that arrives unscheduled or outside its published itinerary is not making a call in the commercial sense; it is making an emergency stop or diversion. Conversely, a scheduled call that the ship's operator cancels for operational or market reasons is marked as a 'blank call' and creates disruption in the supply chain.

Container vessel schedules publish their calls openly, often weekly or bi-weekly on regular trade lanes. A weekly service from Rotterdam to Singapore may make 12 to 18 calls, each 2 to 5 days apart depending on sea distance and port congestion. Bulk carriers and tankers operate differently: they are often chartered for single voyages and make calls only where the cargo contracts direct them. General cargo ships and multipurpose vessels may operate on more flexible, demand-led calling patterns.

Call size has grown sharply. A call that once meant loading 500 TEU (twenty-foot equivalent units) now routinely means 15,000 TEU or more for modern mega-ships at deep-water container terminals. This concentration means fewer but larger calls per route, which reduces frequency but increases the throughput and economic scale per port. A port may handle only one or two calls per week from a major carrier, but each call is a major event for the terminal's crane gangs and truck scheduling.

The term 'call' also appears in port authority communications and bills of lading. A 'port of call' in a contract of carriage is the agreed location where the vessel will stop; it binds the shipowner to deliver to that port within a reasonable time. A 'deviation from the port of call' is a breach unless justified by force majeure or legitimate operational necessity. In container shipping, the actual berth or terminal within a port may shift between calls due to congestion, but the port of call itself is fixed.