A detailed 90-day tracking analysis has uncovered a pattern of ship-to-ship cargo relays operating across the Strait of Hormuz, according to maritime intelligence firm Windward. The findings, published in a September 24, 2026 report, show tankers splitting single cargo movements into two separate legs, obscuring the full journey of certain shipments across the chokepoint.
One Vessel, Fifteen Meeting Partners
According to Windward, a Barbados-flagged product tanker of roughly 40,000 deadweight tonnes was tracked between May 27 and August 27, 2026, operating across two anchorage clusters at opposite ends of the strait. Inside the Gulf, the vessel worked the Basrah and Kuwait anchorages; outside, it operated at Fujairah and Shinas.
Over the 90-day window, Windward recorded 15 distinct meeting partners for this single vessel—more than any other tanker in the reviewed dataset—with four of these transfers corroborated through cargo modeling.
A Two-Leg Structure
Windward describes the pattern as a relay structure: feeder and port tankers hand cargo to the intermediary vessel inside the Gulf, which then transits the strait and hands the cargo onward to different tankers waiting on the Gulf of Oman side. Neither leg is unusual in isolation, as ship-to-ship transfers at anchorage are routine, Windward notes. What stands out is the same vessel repeatedly performing both roles across the review period.
Of the recorded activity, two transfers were confirmed at the parcel level. One involved a load at Basrah between August 5 and 6, tied by Vortexa’s cargo timeline to a fuel oil parcel loaded at Khor Al Zubair, Iraq, on July 9. The second was a discharge at Shinas on July 22, confirmed via IMO match.
Largest Meeting Remains Unconfirmed
According to the report, the largest single event in the dataset—by both duration and tonnage—involved the intermediary tanker holding position alongside a 244-meter, 115,577 deadweight tonne crude tanker at Fujairah for close to 38 hours on August 14 and 15. Windward states this counterpart is Libyan-operated and has been on the Russia sanctions program since May 30, 2026.
However, Windward notes that Vortexa data contains a gap across this meeting window, meaning cargo movement here is inferred from timing and vessel positioning rather than confirmed at the parcel level. The crude tanker had loaded at Yanbu on July 15-16, then went dark for approximately 90 hours crossing the Arabian Sea, before a verified discharge at Sohar on August 18-19.
A Second Tanker, Shared Counterparts
Windward’s report identifies a second product tanker working the identical anchorage pairing—Basrah and Kuwait inside the Gulf, Fujairah and Shinas outside—sharing multiple counterparts with the first vessel. This, according to Windward, points toward a coordinated network rather than two vessels independently following similar commercial logic.
The report also cautions that risk flags attached to some counterpart vessels may be “meeting-driven,” meaning they stem from contact with an already-flagged vessel rather than independent evidence of Iran-linked trade activity.
Does This Matter to You?
For those involved in vetting fixtures, underwriting voyages, or financing cargo movements through the Strait of Hormuz, Windward’s findings suggest that screening the named vessel on a bill of lading may not capture the full picture of a cargo’s journey. According to the report, a clean screening result on one tanker does not account for counterparties on the other leg of a relay that the fixture documentation does not name.
Windward’s analysis also distinguishes between confirmed and inferred transfers, noting that only four of fifteen recorded meetings in this case were corroborated by cargo modeling. The report states that confirmed transfers can support compliance findings, while inferred meetings warrant further investigation rather than direct action.
The report emphasizes that nothing in the dataset constitutes a confirmed sanctions violation. Windward states that visibility into these relay structures depends on holding a full behavioral and meeting history for vessels, rather than relying on single position reports or isolated vessel screens.
Gulf Bunkering does not provide operational or security guidance. This article is for informational purposes only. Operators should consult flag state authorities, P&I clubs, and relevant advisories for decisions relating to transit planning.
Sources: Windward
