Ukraine’s Drone War on Dark Fleet Triggers Diplomatic Tensions, Heightens Black Sea Risk

Rising Tensions Over the Tow of Kairos

A diplomatic row is brewing between Türkiye and Bulgaria over how and why a tug towed the stricken shadow fleet tanker Kairos into Bulgarian territorial waters five days after it was hit by a Ukrainian drone.

Kairos (IMO 9236004) was one of two sanctioned, Russia-trading, shadow fleet tankers hit on November 28 by Sea Baby drones shortly after transiting the Bosporus into the Black Sea.

The unprecedented, deliberate attacks on commercial ships now threaten a global network of more than 650 tankers crucial to Russia’s maritime logistics chain for delivering energy commodities worth billions of dollars to the Kremlin. The incident underscored both heightened security risks in the Black Sea and the dangers of unregulated trade and falsely flagged ships to coastal states.

Kairos and Virat — whose beneficial owners cannot be traced — both falsely claimed to fly the flag of Gambia, rendering the tankers flagless and stateless, and invalidating insurance and certificates of seaworthiness if they had any. This complicated salvage operations for Kairos, leading to the controversial sequence of events that saw a Turkish-flagged tug steer the incapacitated vessel out of Turkish waters toward Bulgaria and then cut the vessel adrift.

Kairos then grounded about one mile from the coast of the Black Sea town of Ahtopol with 10 crew on board, the country’s maritime authority said.

Windward analysis shows the tug towed Kairos (which had its AIS disabled) for about 40 nautical miles out of Turkish waters. Shortly after the tug reached Bulgaria’s territorial waters on December 5, the towing operation ended — reportedly at the request of the crew, according to one account citing the tug operator.

That triggered a Bulgarian border police and naval rescue operation. The crew said they did not want to be rescued but instead towed to a safe area, authorities said. Three men were later removed from the ship on December 7, with more to follow in coming days.

After leaving Kairos, the Turkish tug sailed with no AIS signal until arriving at a berth in a Turkish port 15 hours later.

Bulgaria’s ministry of transportation said in a statement that the tug “moved purposefully” to Bulgaria’s coastline and abandoned the tanker.

Although Kairos is in ballast, it has fuel oil on board.

Escalating Security Risks and Expanding Targets

The parallel drone attacks on Kairos and Virat immediately triggered a sharp rise in war insurance rates for all ships in the Black Sea amid further Ukrainian attacks on Russian infrastructure and broader fears of sabotage against Russia-trading vessels beyond the region.

Two weeks before Kairos and Virat were attacked, another dark fleet tanker, Arlan, was hit by a drone in Novorossiysk during an attack on the port. These activities prompted NATO’s Shipping Centre to warn of serious risks to the safety of navigation, life at sea, and the maritime environment in the Black Sea.

Another Russia-trading tanker, Mersin (IMO 9428683), was crippled by a limpet mine while in floating storage at Dakar, Senegal in late November. The Turkish shipowner said their fleet of tankers would no longer call at Russia. The explosion on Mersin was the latest in at least five mystery attacks on tankers this year after calling at Russian ports.

Adding to uncertainty in the Black Sea were unsubstantiated claims that a Russia-flagged tanker carrying sunflower oil, Midvolga-2, was also attacked around the same time. Ukraine denied responsibility.

The new strategy to attack commercial shipping and assets such as the Caspian Pipeline Consortium oil-loading facility has drawn diplomatic consternation amid broader political pressure on Ukraine from the United States to accept a peace deal and end the war with Russia.

The CPC marine terminal at Novorossiysk, used for Kazakh oil, reported an “intended terror attack of drone boats.” The pipeline is partly owned by Western oil majors including Chevron.

Falsely flagged or sanctioned vessels appear to be Ukraine’s primary target. Windward analysis shows that at least one false-flagged vessel has since transited the Bosporus despite stringent rules and guidelines laid out by Türkiye’s Coastal Safety General Directorate.

Another 252 ships have transited the Bosporus and entered the Black Sea since December 2, including 12 sanctioned tankers.