Experts Sound Alarm as Mysterious “Dark Fleet” Oil Tanker Drifts in Mediterranean

Maritime security experts are raising serious concerns about an uninsured oil tanker displaying erratic movement patterns in the Mediterranean Sea, highlighting growing risks posed by the shadowy network of vessels known as the “dark fleet.”

The Chariot Tide, an 18-year-old tanker believed to be carrying Russian crude oil, has been exhibiting unusual behavior since late January. According to tracking data from MarineTraffic, the vessel departed northern Russia before traversing the Baltic Sea and heading south toward the Strait of Gibraltar, initially signaling Tangier, Morocco as its destination.

As the tanker approached Gibraltar on January 22, it began broadcasting “Not Under Command” signals—an indication that a vessel has lost steering capability or propulsion. Tracking data revealed four tugboats circling the ship as it slowly moved eastward through the strait.

By January 24, the vessel was making peculiar looping movements in the Mediterranean while continuing to travel east at reduced speed. Mark Douglas, an analyst at Starboard Maritime Intelligence, noted that the ship’s heading differs from its actual direction of travel, suggesting it may be at the mercy of strong winds rather than under proper control.

The Chariot Tide isn’t alone in displaying concerning behavior. A second vessel named Progress has also recently signaled “Not Under Command” while navigating Mediterranean waters. Douglas indicates that Progress’s status has since been updated to “In Casualty or Repairing,” while satellite imagery confirms its directional indicators don’t match its actual course.

Michelle Bockmann, senior analyst at maritime intelligence firm Windward, believes Progress was likely transporting Russian crude oil to destinations in India or China—two countries that have increased their purchases of Russian petroleum products since Western sanctions were imposed following Russia’s invasion of Ukraine.

Spanish authorities appear to be monitoring the situation closely, with a search and rescue vessel shadowing the Chariot Tide in international waters as it continues its unpredictable journey.

The situation has heightened environmental concerns across the region. According to Bockmann, the Chariot Tide is falsely registered under the Mozambique flag and, like many vessels in the dark fleet, operates without proper insurance coverage. This legal ambiguity creates significant complications regarding financial responsibility should an oil spill occur.

“The dark fleet is an accident waiting to happen, and it’s unsurprising, in one respect, that we’re seeing vessels having mechanical difficulties,” Bockmann warned.

The term “dark fleet” refers to a network of aging tankers operating outside international regulations to transport sanctioned oil, primarily from countries like Russia, Iran, and Venezuela. These vessels frequently employ deceptive practices, including turning off location transponders, falsifying registration documents, and operating without adequate insurance or safety inspections.

Maritime safety experts have repeatedly warned about the increasing risks posed by this shadow fleet. Many of these vessels are significantly older than the industry average, poorly maintained, and operated by crews with questionable training. The combination creates perfect conditions for mechanical failures or navigational errors that could lead to environmental disasters.

The Mediterranean Sea, one of the world’s busiest shipping corridors and home to fragile marine ecosystems, would be particularly vulnerable to a major oil spill. Local economies dependent on tourism and fishing across countries like Spain, Italy, and Greece could face devastating consequences from such an incident.

As Western sanctions on Russian oil exports continue, the prevalence of these high-risk vessels is expected to increase, creating ongoing challenges for maritime authorities trying to monitor their movements and mitigate potential disasters.