Ocean cargo vessels usually have a fixed route and ports of call that are known as Schedules.
The schedule includes the vessel’s ETA (Expected Time of Arrival at the port) and ETD (Expected Time of Departure from the port).
An ocean vessel has a fixed number of days to complete the schedule and get back to its base. The ship takes cargo from these ports and discharges them as per their bookings at the respective ports of discharge.
The ship’s voyage might also include stops for routine bunkering and other maintenance of the vessel.
When an ocean vessel does not call at one or more of its scheduled intermediate stops, it is called a blank sailing or void sailing from these ports.
It could be from one or two specific ports or the entire voyage could be cancelled.
When the entire voyage is cancelled it is called ‘blanking the string’. Customers who have been waiting to load or offload cargo will find that they have to wait for the next sailing to pick up or drop-off their cargo.
The list of ports that are served by the carrier is called a ‘string’.
Let us say, a carrier sails between port A and port D. In this case, the carrier sets sail from port A, reaches port B, then C, and finally its destination port of D.
At port D, it offloads goods as well as takes in goods meant for port A. It then sails for port A.
These ports from A to D is called the string.
As it can be seen here, the vessel completes a circle and reaches back at the port from where it started.
The voyage taken by the vessel is usually in a fixed ‘circle’, in the same direction, with a timetable of fixed arrivals and departures at these ports.
Blank or void sailing may be understood better with the following example.
A vessel has a schedule from the Port of Tangier in Morocco to the Jeddah Port, Saudi Arabia, as follows:
1. Vessel sets sail from Tanger Med terminal on 19 November.
2. Arrives at Algeciras in Spain on 20 November and sails out on 21 November.
3. Arrives at Valencia in Spain on 22 November and leaves on 23 November.
4. Arrives at Fos Sur Mer, France on 23 November and departs on 24 November.
5. Arrives at Port Vado Ligure, Genoa, Italy on 25 November and sails out 26 November.
6. Arrives at Jeddah port, Saudi Arabia on 1 December.
If the above vessel had no cargo to pick up from Fos Sur Mer port and let us say there was a severe labour problem at Vado Ligure port threatening to delay berthing and sailing of vessels, the ship may decide to skip both Fos Sur Mer and Vado Ligure and sail for Jeddah directly from Valencia.
In this case, Fos Sur Mer and Vado Ligure will have blank sailings.
Cargo that was meant for Vado Ligure and Fos Sur Mer will be offloaded at Valencia to catch the next ship to these destinations and cargo meant to be loaded from the Vado Ligure will have to wait for the next ship to pick it up. This might take a week or more depending on the sailing schedule.
As we can see in the above example, two ports in the string had blank sailings – Fos Sur Mer and Vado Ligure. The blank sailings resulted in cargo to these ports being offloaded at Valencia to take the next to ship sailing to these ports.
It also resulted in the cargo from Vado Ligure not being lifted.