Vessel had been falsifying its position late last year

When the tanker SKIPPER (IMO 9304667) was intercepted and boarded by the U.S. Coast Guard on Dec. 10, 2025, U.S. authorities said that the vessel was stateless, having falsely claimed to be flagged to Guyana. They also stated the ship was previously sanctioned as part of a network financing Hezbollah and the Islamic Revolutionary Guard Corps-Qods Force (IRGC-QF).

Of interest to us, however, was the claim that the tanker had been falsifying its position broadcast on the automatic identification system (AIS). We analyzed the vessel’s track since the start of 2025 and can confirm three episodes of position falsification.

A brief instance of outside global navigation satellite system (GNSS) interference on July 5 is highlighted below.

A very likely intentional AIS manipulation occurred July 5-9 in the Persian Gulf, shown above and below.

And finally, a much longer period of likely falsification from Oct. 27 to Dec. 8, along the north coast of South America can be seen below.

The brief instance of GNSS interference, from 16:34 to 17:07 UTC on July 5, caused vessel positions to jump into a circling pattern at an oil terminal near the Iranian town of Bidkhun. This type of outside interference in GNSS has become increasingly common with many GPS users affected.

Just a few hours after this interference, we found that the vessel operators had likely begun falsifying their location. This can be seen by AIS patterns that don’t reflect realistic vessel movement. The false data was confirmed by an overpass of the European Space Agency (ESA) Sentinel-1 satellite on July 6 at 02:39 UTC during which no vessel was visible at the location the SKIPPER was broadcasting on AIS. At 333 meters in length, the SKIPPER should show clearly on Sentinel-1 radar imagery.

Our analysis reveals vessel operators likely continued to falsify their track through July 9, showing the tanker going to the northwest Persian Gulf near Iraqi waters. We were curious where the tanker actually went during the period of track falsification. We contacted Samir Madani of TankerTrackers.com, who shared that the tanker appeared at an oil terminal on Iran’s Kharg Island on July 8.

After presumably loading crude oil at the Kharg Island terminal, the vessel made its way to the Chinese coast and then returned to the Persian Gulf. AIS analysis and image correlation show accurate position broadcasts during this period. The vessel then proceeded around South Africa and to the northern coast of South America where it appeared to be adrift within Guyana’s EEZ for more than a month.

Our analysis shows that during this period, from Oct. 27 to Dec. 8, the vessel was likely falsifying its location. This could be confirmed by correlation with several Sentinel-2 satellite optical images. The New York Times also published imagery of the vessel at Venezuela’s Jose oil terminal on November 18, a time when the vessel was broadcasting a position in Guyana’s waters.

Since the SKIPPER was detained on Dec. 10 and eventually brought to the port of Galveston, Texas, there have been operations against six additional tankers in the region. The tanker CENTURIES (IMO 9206310), flying a valid Panamanian flag, was detained on Dec. 20. Interestingly, CENTURIES also had a long history of falsifying its location. There was also an attempted detention of the tanker BELLA I (IMO 9206310) on Dec. 20, which fled eastwards into the Atlantic Ocean before being boarded on Jan. 7. BELLA I is also a stateless vessel, initially falsely claiming to be on the Guyana registry, then stating that it had reflagged to Russia.

The SKIPPER is just one example of how a vessel may intentionally falsify its location, called “spoofing,” which may be done to avoid sanctions or hide illicit activities like illegal fishing or pollution. Spoofing has been one area of focus for our work for the past few years–explore that research and analysis through our past coverage.