The use of new techniques to disguise the movement of “dark fleets” is increasing rapidly as owners try to avoid economic and reputational damage of being identified as carriers of sanctioned oil, according to new research.

The events represent a technological advance on the tactic of “going dark” when ships turn off AIS systems to enter ports unnoticed or carry out ship-to-ship transfers of sanctioned oil, according to data firm Windward.

The Israel-headquartered technology company said that since early 2021 it had identified 265 vessels involved in 600 cases of a new wave of tampering with global navigation satellite systems to disguise a vessel’s true location.