Selective Enforcement: Saudi Crude Keeps Moving Under the Houthi Blockade

A Blockade, Declared and Partly Kinetic

On July 20, Houthi-aligned forces announced a full naval blockade of Saudi Arabia, framed as retaliation for Saudi strikes on Sanaa airport. The declaration named Saudi, Israeli, and U.S.-linked tonnage as targets.

Within days, Houthi channels claimed strikes on two Saudi tankers. One is corroborated: UKMTO logged a projectile strike on the products tanker Encelia (IMO 9240172) roughly 70 nautical miles southwest of Al Shuqaiq, with a fire aboard and no casualties or pollution reported, and Saudi Arabia’s Transport General Authority confirmed the vessel was hit and its crew safe. The second claim is not. The tanker named in it, the Bahri-managed VLCC Layla (IMO 9336098), has been AIS-dark since July 17, and no independent source has matched it to a strike.

A July 22 joint maritime warning reported Houthi missiles and drones positioned to enforce the embargo, and the EU naval mission Aspides advised Israeli, U.S., and Saudi-linked vessels to avoid the Red Sea and Gulf of Aden. By the numbers, the blockade reads as active and dangerous. By vessel behavior, it reads as something narrower.

What the Data Shows: The Crude That Sailed Anyway

In the window after the declaration, two China-linked tankers loaded Saudi crude at Yanbu on July 20 and transited Bab al-Mandeb southbound, apparently unimpeded. Both were bound for China with early-August ETAs, and both transmit China crew and China ownership. Combined, roughly 3.96 million barrels of Saudi crude moved through the strait after the blockade was announced.

That is the detail the news cycle misses. The declaration named its targets by affiliation. Windward tracking shows the cargo moving through the chokepoint was Saudi in origin but Chinese in crew and destination, and it drew no interdiction. The two vessels held course through the same corridor that Western- and Saudi-linked operators were being warned to avoid.

Read against the target list, the pattern is consistent with enforcement calibrated to affiliation rather than cargo. The blockade is shaping who moves Saudi crude, not whether it moves.

The Other Side of the Strait

The same posture, concealment as the default and enforcement as the variable, shows up 1,500 miles east in the Strait of Hormuz.

A single multi-source SAR pass over Hormuz on July 23, analyzed by Windward’s Maritime Intelligence Operations Center, detected 19 vessels running dark with no AIS: 10 inbound, 8 outbound, 1 stationary. The same collection surfaced two active oil spill detections, one trailing from a stationary hull and one at an onshore facility.

The gap between declared voyages and actual behavior runs through Saudi-bound traffic too. Of 14 tankers reporting the Red Sea or Saudi Arabia as their destination, Windward and Vortexa data show a consistent divergence between what they broadcast and what they do:

• Three went dark in the Gulf of Aden.
• Two diverted course while still transmitting AIS.
• Three Saudi-flagged tankers switched off AIS.

The vessels that went dark or diverted are sailing in ballast, consistent with intent to load at Yanbu rather than deliver against their reported destination.

Why It Matters

For compliance, insurance, and routing teams, a declared blockade is a blunt input. The operational question is narrower: which cargoes actually stop, and which keep moving. The July 20 to 23 picture indicates that Saudi crude continues to reach buyers when it travels under crew and ownership outside the named target set, even as the same corridor becomes higher-risk for Western- and Saudi-linked tonnage.

That has two consequences. Rerouting and rate decisions built on the headline “Red Sea closed to Saudi crude” will misprice the risk, because the corridor is closed selectively, not absolutely. And screening that stops at flag or declared destination will keep missing what predicts a clean transit: the AIS gaps, the ballast diversions, and the crew-and-ownership profile behind the vessels that pass through untouched.

What to Watch

The open question is whether enforcement stays selective. If it does, China-crewed and China-destined tonnage looks like a standing route for Saudi crude even under a declared blockade. The signal to watch is whether the Houthis extend interdiction to non-Western-linked vessels carrying Saudi cargo. Until then, the corridor stays open to the right profile of vessel, and Saudi crude keeps finding its way to China.

Windward is tracking vessel activity across the Strait of Hormuz and the Red Sea in real time on the Maritime AI™ platform.