Maritime glossary · STS
Ship-to-Ship Transfer
The transfer of cargo directly between two vessels at sea, routine in trade but also used to obscure origin.
Definition
A ship-to-ship transfer moves cargo, usually crude oil or products, directly between two vessels moored alongside each other at sea or at anchor. STS is a legitimate and common operation, used to lighter a deep-draught tanker or to aggregate parcels. It also features in sanctions evasion, where cargo is passed between ships, often with AIS switched off, to break the paper trail back to a sanctioned origin. Location, frequency, and the partner vessel are what mark an STS as suspect.
How Vessel Hunter uses Ship-to-Ship Transfer
Vessel Hunter reads the position and status patterns that point to an STS, so the operation, and the partner hull, are visible in the record.
Related terms
- AIS GapGoing Dark
A period when a vessel stops transmitting AIS, sometimes innocent, sometimes a sign of evasion.
- Sanctioned Vessel
A ship designated under a sanctions regime, or trading in breach of one, which is barred from much of the market.
- Oil Tanker
A tanker built to carry crude oil or refined petroleum products in bulk liquid form.
- Anchorage
A designated area off a port where vessels anchor to wait for a berth, orders, or tide.
The bigger picture
Ship-to-Ship Transfer is one piece of the commercial maritime picture Vessel Hunter pulls together for shipyards, suppliers, service providers, and port agents. Every vessel record bundles AIS, ownership, inspections, dry-dock history, casualty record, classification status, and a verified contact for the operator decision-maker behind the ship, so the team that reaches out first wins the work.
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