The covert tanker network keeping Gulf oil moving through Hormuz

How the “dark” tanker system works

The system is best understood as a shuttle operation rather than a conventional export route:

1. Smaller tankers or shuttle vessels load crude in the Persian Gulf.
2. They switch off their automatic identification system, or AIS, to stop broadcasting their location and route.
3. The vessels cross the Strait of Hormuz despite the sharply reduced public traffic.
4. In the Gulf of Oman, the cargo is transferred to larger tankers that can continue toward international markets.

Satellite imagery identified 12 ship-to-ship oil transfers along the Omani and UAE coasts on August 10. The transfers indicate that some vessels are still crossing Hormuz “dark,” even as publicly tracked traffic has fallen dramatically.

This method does not make the strait open in any normal commercial sense. Kpler data cited by the BBC showed only eight to 11 ships passing on two days in early August, compared with more than 100 per day before the war. CNN separately reported that 84 vessels crossed during one week—around 20% of the traffic expected before the conflict.

Why the flows are limiting the oil-price shock

The covert shipments preserve a supply valve at a time when openly visible traffic is close to a standstill. That physical flow can reduce the immediate shortage, while evidence that oil is still leaving the Gulf may also limit panic buying and the risk premium in crude markets. Reporting on the shipments says they are helping keep prices from surging, although the cited material does not independently establish a precise Brent range or prove that the covert trade alone determines prices.

The important distinction is between stabilizing supply and securing supply. More than 4 million barrels per day is meaningful, but it is still far below the pre-war level. A disruption to the transfer areas, a further decline in willing crews or shipowners, or a successful attack on a dark-running tanker could remove a large portion of the remaining flow quickly.

Why the flow estimates do not agree

The central number is contested because AIS-off voyages are difficult to observe. Analysts can miss vessels that broadcast no location data, while cargoes can potentially be counted more than once when oil is recorded both before and after a ship-to-ship transfer. The available estimates include:

• More than 4 million barrels per day: a figure attributed to analysts and people familiar with the covert shipments.
• Nearly 9 million barrels per day: a public estimate from U.S. Energy Secretary Chris Wright.
• About 4 million barrels per day: a lower estimate attributed to JPMorgan and cited by CNN.
• Around 3 million barrels per day: Barclays’ estimate for combined crude and product net exports for the week ending August 7, according to a timeline compiling market estimates.

These figures are not directly comparable: some refer to crude alone, some to crude and petroleum products, and some may include different time windows or routes. The safest conclusion is that material volumes are leaving the region, but no single estimate should be treated as a precise real-time count.

The ADNOC attack figures are also being reported differently

Reports about attacks on UAE-linked or ADNOC vessels appear inconsistent until the dates and counting methods are separated.

Reuters reported that one ADNOC-linked vessel was targeted on August 8, while another Reuters report said two ADNOC vessels were attacked on August 13. A further report dated August 14 described an attack on one ADNOC vessel.

Those incident reports do not necessarily contradict ADNOC’s broader August 7 statement that 15 of its vessels had been attacked since the conflict began, including three during that week. Earlier, two Emirati tankers, the Mombasa B and Al Bahyah, were reported struck, killing one Indian crew member and injuring eight others.

The difference is therefore mainly one of time frame and scope: a report may describe a single new incident, while ADNOC’s cumulative figure covers attacks over the course of the conflict. The supplied reporting also uses different descriptions, including ADNOC-owned, ADNOC-linked and targeted vessels, so the figures should not be combined without checking the definition.

The risks for crews, owners and cargoes

Sailing without AIS creates an additional hazard in an already dangerous waterway. A vessel that is not broadcasting its position is harder for other ships, naval forces and rescue services to identify. Night crossings and transfers add risks involving navigation, collision, fire and emergency response.

The vessels also face missile and drone attacks. In July, the strikes on two Emirati tankers killed one crew member and wounded eight. A Qatari LNG tanker was later damaged near Hormuz, with the ship’s engine-room fire creating an explosion risk before the crew was evacuated.

For owners, the commercial risks extend beyond physical damage. The crisis has produced diversions, delays, cargo exposure and severe insurance problems. Brookings reported that insurance for vessels transiting the strait had become unavailable or prohibitively expensive, while seafarers were unwilling to make the journey.

Why alternative infrastructure cannot replace Hormuz immediately

The UAE’s Fujairah route is useful but limited

The UAE can partially bypass Hormuz through the Abu Dhabi Crude Oil Pipeline, which connects inland production to the Fujairah terminal outside the strait. The route has a reported current capacity close to 1.8 million barrels per day, and the UAE was still exporting around that level—roughly half its pre-war output—even after Fujairah was disrupted by Iranian fire.

A new West–East pipeline is intended to double ADNOC’s export capacity through Fujairah. But the project is expected to become operational in 2027, not immediately, and therefore cannot close the current supply gap.

Saudi Arabia’s Petroline cannot serve every Gulf exporter

Saudi Arabia’s East–West pipeline, or Petroline, can move crude from the kingdom’s eastern oil fields to Yanbu on the Red Sea. Reuters reported a nameplate capacity of up to 7 million barrels per day, but effective exports were estimated at about 4.5 million barrels per day depending on tanker and jetty availability.

That capacity is not an instant substitute for all Hormuz traffic. It depends on available infrastructure, storage, terminals, tankers, security and the grades of crude that can be moved. It also cannot directly carry exports originating in Kuwait, Qatar, Iraq or the UAE.

Qatar’s LNG exports are especially dependent on shipping

Oil pipelines cannot solve Qatar’s LNG problem. Qatar’s gas exports must reach overseas buyers by sea, leaving them exposed to the same maritime danger. Reuters reported that the Qatari LNG carrier Al Rekayyat was stranded off Oman after a strike caused an engine-room blaze and created an explosion risk.

Separately, QatarEnergy said Iranian attacks had damaged two of Qatar’s 14 LNG trains and one of its gas-to-liquids facilities, knocking out an estimated 17% of LNG export capacity. That loss cannot be immediately replaced by redirecting crude through a pipeline.

China is the market’s major unknown

China’s strategic and commercial crude inventories could influence how quickly the disruption reaches global prices. If Chinese companies or the government draw on stored oil, that could reduce immediate competition for scarce seaborne barrels. If China instead builds inventories or competes aggressively for remaining cargoes, the pressure on the market could intensify.

The supplied reporting does not establish the size, accessibility or release policy of China’s usable reserves. That makes China an important uncertainty rather than a dependable source of relief.

A supply lifeline, not a return to normal

The dark-tanker network shows that Hormuz is not simply “open” or “closed.” Some oil is still moving through a highly constrained and difficult-to-measure channel, supported by risky crossings and transfers off Oman.

But the arrangement depends on vessels willing to sail into a severe threat environment, crews willing to operate in it, insurers willing to cover it and transfer points that remain accessible. With reported flows ranging from roughly 3 million to 9 million barrels per day, the market can see the direction of supply more clearly than its exact scale.

For now, covert shipments are softening the shock. They are not making Gulf energy supply secure. A new attack, tighter insurance restrictions, fewer available crews or a change in Chinese buying could turn this managed shortage into a much larger oil and LNG disruption.