What’s it mean? Service slings and blank sailings

As people go back to work in Asia, we expect carriers to get creative with their shipping. Techniques will probably include service slings and blank sailings. We’re explaining both here.

What is a Service Sling?

Service Sling

A service sling is a steamship line’s regular service schedule calling on the same port rotation in a loop. The sling is usually weekly and has a fixed arrival and departure day at each port.

For example COSCO’s AAC4 service sling.  A weekly service between Ningbo, Shanghai, Long Beach, and the Korean port Pusan (COSCO website).


What is a blank sailing?

Blank sailings occur when an ocean carrier determines there is not enough cargo to justify a vessel sailing a route or a stop at a port call. Sometimes a blank sailing will only result in the ship skipping one or two ports along its route, or the carrier will cancel the entire service sling for one week.

For COSCO’s AAC4 service sling example, the vessel might not stop at Shanghai for one week. Or it may take the entire service sling out of rotation for one week.  Either occurrence is considered a blank sailing.

Why do blank sailings happen?

Blank sailings usually occur when overall container volumes are low.  The carriers will blank sailings in order to take vessel space out of the system to keep space tight and keep rates from dropping.  For example, container volumes might be slow at the beginning of the year, so carriers will use blank sailings to keep capacity tight and rates elevated.

Carriers may also blank sailings when joining services with other carriers in an alliance or when adding larger vessels into an existing service sling.

How do blank sailings affect your shipment?

If your cargo was booked on a sailing that has been canceled, it will be rescheduled to move on the next available sailing, which can be frustrating for importers.

Sea-Intelligence forecasted an average of about six cancellations a week on the trans-Pacific in the first five weeks of 2022.