When a cargo vessel goes dark — switching off its AIS transponder in international waters — it leaves a gap in the record. That gap is evidence. The absence of a signal, documented correctly and cross-referenced against satellite imagery, is as investigatively significant as the signal itself. AIS is not just a tracking tool. It is a forensic layer, and knowing how to read it — including its silences — is a foundational skill for anyone working maritime investigations, sanctions research, or conflict reporting.
MAR-001 is the Signal & Shadow reference card for AIS and MMSI vessel tracking. It covers the full workflow: from obtaining a vessel's MMSI and querying MarineTraffic's historical playback, through cross-referencing on VesselFinder, pulling ownership and flag state data from Equasis, verifying MMSI registration against ITU MARS, and documenting dark periods and AIS gaps to a standard that holds up in an editorial or legal context.
This is the first card in the Signal & Shadow Maritime Intelligence series. It is free to download — no payment required, just your email address. The full maritime series runs to eight cards, all available to Signal subscribers.
This reference card is for Signal subscribers.
Signal subscribers get the full OSINT Reference Card library — plus every Methods tutorial and Forensic Dossier.
Join SignalA Signal subscription gives you:
- Full OSINT Reference Card library
- Methods — all tradecraft tutorials in full
- Shadow Analysis — all evidence-based reporting
- Forensic Dossiers — full access
- Discord access included
