Bunker suppliers and other marine service companies should not rely on declared vessel identity, sanctions-list screening and AIS voyage histories alone for compliance checks, according to an 8 September analysis by Israeli maritime intelligence provider Windward.
The company said vessel screening should also incorporate behavioural intelligence, ownership information and checks for deceptive shipping practices as manipulated positioning and false registration make conventional checks less reliable.
A separate Windward analysis published on 8 September found that 393 of 642 vessel transits logged through the Strait of Hormuz in August, or 61.2%, had not taken place and were artifacts created by GPS jamming that corrupted AIS positioning. Independently measured vessel traffic was only 1.2% lower during jamming periods than during quiet periods.
The data follows Windward’s Q2 2026 analysis, which identified 275 internationally trading tankers broadcasting the flag of a fraudulent registry through AIS, down from 290 in the first quarter.
Windward identified 22 fraudulent ship registries, with around 90% of tankers using them subject to Western sanctions.
Russia-linked tankers also began claiming Syrian and Myanmar registration during the quarter, although neither country operates an international ship registry.
GPS interference generated 1.24 million false ship-to-ship meetings in Q2, with manipulated positions making vessels appear to rendezvous when no meeting had taken place. The 275-tanker and 1.24-million-meeting figures were Q2 findings and were not first disclosed in September.
Windward had already warned bunker operators in June to extend checks beyond sanctions lists to behavioural patterns, ownership structures and flag histories, and to verify vessel movements using sources beyond AIS where positioning data may be compromised.
EU measures adopted on 23 July expanded existing restrictions to vessels supporting the shadow fleet through services including bunkering. The EU added 41 vessels to 632 ships already covered by the measures, including five bunkering vessels.
Windward began operations in Israel in 2010 and provides maritime intelligence using behavioural analytics and multiple data sources. It has operations in London, Tel Aviv, Washington DC and Singapore.