Ship-to-ship transfers are a documented mechanism for obscuring the origin or destination of cargo under sanctions. By transferring oil, grain, or other commodities at sea, outside port jurisdiction and beyond direct customs oversight, sanctioned actors insert a step in the supply chain that breaks the paper trail between producer and end buyer. The technique is not new, but its scale and geographic spread have expanded materially since 2022 in response to expanded sanctions regimes targeting Russian, Iranian, and North Korean maritime activity.
Open-source investigators can identify and document these transfers using a combination of AIS analysis, satellite imagery, and financial intelligence. The core indicators are well-established: AIS-off periods in open water, vessel rendezvous patterns at known transfer zones, flag changes and name changes in close proximity to a transfer event, and mismatches between declared cargo, destination ports, and known buyer networks. Each indicator, individually, is ambiguous. The pattern, corroborated across sources, is not.
MAR-007 sets out the methodology for identifying, documenting, and presenting ship-to-ship transfer evidence. It covers the primary data sources for AIS and satellite corroboration, the sanctions list databases relevant to maritime investigation, the known transfer zones and the monitoring tools that cover them, and the documentation standards required to present transfer evidence at evidentiary quality in a published investigation.
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