Vessel-tracking data suggests the Houthi blockade of Saudi Arabia announced on July 20 is being enforced selectively, allowing Saudi crude bound for China to keep moving even as Western- and Saudi-linked tankers face heightened risk, according to Windward.
The Blockade Declaration
Houthi-aligned forces declared a full naval blockade of Saudi Arabia on July 20, describing it as retaliation for Saudi strikes on Sanaa airport, according to Windward. The declaration specifically named Saudi, Israeli, and U.S.-linked shipping as targets.
Within days, Houthi channels claimed strikes on two Saudi tankers, Windward reports. One incident was corroborated: UKMTO logged a projectile strike on the products tanker Encelia (IMO 9240172) approximately 70 nautical miles southwest of Al Shuqaiq, with a fire reported aboard but no casualties or pollution. Saudi Arabia’s Transport General Authority confirmed the vessel was hit and that its crew was safe, per Windward.
The second claimed strike, involving the Bahri-managed VLCC Layla (IMO 9336098), could not be verified. Windward notes the vessel has been transmitting no AIS signal since July 17, and no independent source has linked it to an attack.
A joint maritime warning issued July 22 reported Houthi missiles and drones positioned to enforce the blockade, and the EU naval mission Aspides advised Israeli, U.S., and Saudi-linked vessels to avoid the Red Sea and Gulf of Aden, according to Windward.
Crude Still Moving Through the Corridor
Despite the declared blockade, Windward’s tracking data shows two China-linked tankers loaded Saudi crude at Yanbu on July 20 and transited Bab al-Mandeb southbound without apparent interdiction. Both vessels, bound for China with early-August arrival estimates, transmit Chinese crew and ownership details, Windward reports. Combined, the two tankers carried roughly 3.96 million barrels of Saudi crude through the strait after the blockade was announced.
Windward’s analysis indicates enforcement appears calibrated to vessel affiliation rather than cargo origin, meaning the blockade is influencing who transports Saudi crude rather than halting its movement altogether.
A similar pattern of concealment emerged in the Strait of Hormuz. A multi-source SAR pass conducted on July 23, analyzed by Windward’s Maritime Intelligence Operations Center, detected 19 vessels transiting without AIS signals, along with two active oil spill detections.
Additionally, Windward and Vortexa data covering 14 tankers reporting Red Sea or Saudi Arabia destinations found discrepancies between declared routes and actual movements: three vessels went dark in the Gulf of Aden, two diverted course while still transmitting AIS, and three Saudi-flagged tankers switched off their AIS systems. Windward notes these vessels were sailing in ballast, consistent with plans to load cargo at Yanbu.
Does This Matter to You?
According to Windward, the divergence between declared blockade conditions and actual vessel behavior has direct implications for compliance, insurance, and routing decisions. Rerouting and rate calculations based solely on headline reports of a closed corridor may misprice risk, since Windward’s data indicates enforcement is selective rather than absolute.
Windward further states that screening processes relying only on flag state or declared destination risk missing key indicators, such as AIS gaps, unexplained ballast diversions, and crew-and-ownership profiles, that appear to determine whether a vessel transits the corridor without incident.
Windward reports the central question going forward is whether Houthi enforcement remains selective or expands to include non-Western-linked vessels carrying Saudi cargo. Windward states that until this changes, the corridor remains open to certain vessel profiles, with Saudi crude continuing to reach Chinese buyers.
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
