A blank sailing is a scheduled voyage that a carrier cancels — the ship skips a port, or the whole rotation is pulled for a week. Carriers blank sailings to match capacity to demand, around holidays, and when a vessel runs late enough that catching up means dropping a call. For the cargo booked on that voyage, the result is the same: it waits for the next ship.
Across the 1.2 million ocean shipments we tracked over the past year, 7.4% were affected by at least one blank sailing. In the weeks around Lunar New Year that figure passed 20%.
The ETA was never wrong. The ship it was attached to simply didn’t sail.
Why your ETA finds out last
Carriers announce blank sailings in advisories, customer e-mails, and schedule files that update on their own rhythm. The booking confirmation your team filed three weeks ago still shows the original vessel and the original date. Until something re-reads the schedule, the ETA on your board is a promise about a ship that no longer exists.
Windrose watches three signals for every booking: the carrier’s published schedule, the vessel’s actual AIS track, and the terminal’s loading events. When a scheduled vessel is still 900 nautical miles away on the day it should be loading, the model stops believing the schedule and says so.
What a good ETA does about it
- Flags before it moves. Confidence drops as soon as the schedule and the AIS track disagree — typically five to nine days before the carrier confirms the blanking.
- Re-plans on the next realistic vessel, not the next scheduled one, using how the same carrier handled blankings on the same lane before.
- Tells an owner. A blank sailing is a Medium exception: the plan changed, no promise is broken yet. It lands on the shipment owner, not in a channel.
Three things to do this quarter
- Stop treating the booking date as the ETA. It is an intention, not a prediction.
- Add a blank-sailing rule for your top five lanes so a roll becomes a task with a name on it.
- Measure roll notice: how many days before departure you learned about the blanking. Ours averages 6.2 days; anything under two is a carrier conversation.
Blank sailings aren’t going away — they are how liner shipping manages capacity. The goal is not to prevent them but to find out early, and to make the first person who finds out a system rather than a customer. That is what the ETA engine is for.