In late February 2025, United States forces intercepted and boarded the tanker BERTHA (IMO 9292163) in the Indian Ocean. This was the second interdiction of a sanctioned vessel in the region that month. While global tracking platforms and media outlets have widely identified the vessel as Cook Islands-flagged, a technical analysis reveals a sophisticated example of identity manipulation—a common tactic used to obscure a vessel’s true origin and legal status.
The Discrepancy Between Broadcast and Registry
The confusion regarding the BERTHA’s flag state stems from its Automatic Identification System (AIS) broadcast. The vessel is currently transmitting a Cook Islands Maritime Mobile Service Identity (MMSI) and associated callsigns. In isolation, this broadcast suggests a legitimate registration. However, when this data is compared with IMO records, a contradiction emerges: the IMO database lists the vessel as falsely flagged, with the false registration recorded as Curaçao.
Technical Verification via National Portals
To resolve such discrepancies, Starboard Maritime Intelligence cross-references AIS data with the IMO global shipping database. In the case of BERTHA, there is a clear mismatch between the vessel’s flag—as indicated by the three-digit MID at the start of its MMSI—and the flag registered in the IMO database. Furthermore, the IMO database notes that the registered flag, Curaçao, is actually false. This indicates the vessel is operating without a recorded flag, which is in direct contravention of the United Nations Convention on the Law of the Sea (UNCLOS).
BERTHA Vessel report showing the mismatch between the flag information transmitted by the vessel, and the information held on the IMO global shipping database
The Role of Shadow-Fleet Operations
This form of digital deception is a hallmark of shadow-fleet operations. By manipulating MMSI numbers and callsigns, sanctioned vessels attempt to blend into commercial traffic, evade oversight, and operate without necessary flag-state oversight, classification society certification, or protection and indemnity (P&I) insurance.
Exposing these hybrid threats requires moving beyond single-source data. Effective Maritime Domain Awareness (MDA) is achieved by fusing AIS movements, ownership structures, registry status, and sanctions information into a single Common Operating Picture (COP).
Why This Matters for Maritime Security
The BERTHA incident underscores the limitations of legacy tracking systems that rely on unverified AIS data. In complex maritime environments, the ability to rapidly identify identity manipulation is critical for:
Operational Decision-Making: Providing the high-confidence intelligence required to authorise physical interdictions.
Risk Mitigation: Identifying uninsured or "de-classed" vessels that pose environmental and safety risks to coastal states.
Sanctions Enforcement: Tracking the movements of vessels involved in the illicit trade of sanctioned commodities.
By integrating disparate data sets, maritime authorities can move from simple observation to the level of intelligence required to expose deceptive practices and maintain regional security.