DUBAI | Gulf oil exporters have used a large network of ship-to-ship transfers outside the Strait of Hormuz to keep crude moving during the war with Iran, according to a Reuters investigation that attributed part of the system's protection and coordination to U.S. surveillance while U.S. Central Command denied that American forces were participating in the transfers.
Reuters identified at least 92 vessels involved in transfers near ports in the United Arab Emirates and Oman and estimated that as much as 90 million barrels may have moved through the system since early May. The estimate was based on shipping data, satellite analysis and interviews; it is not an official audited total.
The operation borrowed a technique associated with sanctioned oil trades: one tanker meets another at sea and transfers cargo between them. In this case, the economic purpose was to move oil around a disrupted chokepoint. The similarity of method does not establish that every cargo or participant was violating sanctions.
Why exporters needed a workaround
The Strait of Hormuz normally carries about one-fifth of global oil consumption. Conflict, attacks and military restrictions made ordinary transit dangerous or unavailable, threatening revenue for Gulf producers and supply for global buyers.
Exporters with pipelines to ports outside the strait have some alternatives, but capacity is limited. Ship-to-ship transfers can connect cargo loaded inside the Gulf with vessels positioned beyond the most dangerous area.
The process is slower and more expensive than normal loading and transit. It requires two ships, compatible equipment, favorable weather and extensive coordination. It is an emergency bridge, not a full replacement for a freely operating waterway.
How a transfer works in broad terms
Two tankers position alongside each other or in a controlled configuration, secure lines and connect hoses. Crews balance pumping rates, pressure and vessel stability while monitoring weather and sea conditions.
Transfers can take many hours. Reuters reported durations of roughly 24 to 40 hours in the network it examined. The time depends on cargo volume, vessel size and conditions.
These are established maritime procedures when conducted under proper standards. The risk increases when operations occur under wartime pressure, with reduced lighting or incomplete tracking signals.
Tracking signals and transparency
Commercial vessels normally broadcast Automatic Identification System information that helps other ships and authorities understand identity, position and movement. Reuters reported that some vessels involved in the transfers disabled signals or dimmed lights.
AIS can be turned off for legitimate security reasons in a high-risk area, but loss of tracking reduces transparency and can increase collision risk. It also makes it harder for insurers, port officials and researchers to verify cargo movements.
Satellite images and other data can fill part of the gap, but they require interpretation. A vessel seen near another vessel does not alone prove a transfer or identify the cargo. Reuters combined several forms of evidence in its estimate.
The disputed U.S. role
Reuters cited sources who said American surveillance and military assets helped monitor or secure elements of the operation. A U.S. defense official speaking for Central Command denied that U.S. forces were participating in ship-to-ship transfers.
Those statements can coexist in limited ways if U.S. forces provided general regional security without directing commercial transfers, but the public reporting did not resolve the boundary. “Oversight,” “protection,” “coordination” and “participation” are not interchangeable terms.
The Pentagon should clarify the legal authority, mission and limits of any support without releasing operational details that would endanger personnel or ships. Congress may also seek classified briefings.
An Apache loss raises additional questions
Reuters reported that a U.S. Apache helicopter downed on June 9 may have been connected to activity protecting the transfer network, while noting that it could not independently confirm the aircraft's role. That claim should remain attributed and unresolved.
Military losses require formal investigation. The service should establish the mission, cause and circumstances before officials or media connect the aircraft to a specific commercial operation.
Public accountability does not require disclosure of tactics during an active conflict. It does require an eventual record explaining how forces were used and what risks were accepted.
Scale matters, but context matters more
Ninety million barrels is a large quantity, but it was accumulated over weeks and remains small compared with the roughly 20 million barrels a day that typically move through Hormuz. The workaround could soften the shock without restoring normal trade.
Reuters counted 17 vessel pairs involved on June 11, illustrating the logistical intensity. A larger network requires more crews, equipment, inspection and staging areas.
Capacity is constrained by the number of suitable vessels and safe locations. The system cannot expand indefinitely without increasing congestion and risk.
Environmental danger
Transferring crude at sea creates a spill risk. Hose failure, collision, sudden weather or human error can release oil. Cleanup can be difficult, particularly during conflict or when responsibility is disputed.
Operators should have response equipment, trained crews and clear reporting obligations. Coastal states need access to plans and liability coverage. Reduced tracking signals should not prevent rapid notification after an incident.
A large spill near Oman or the UAE could affect fisheries, desalination facilities, beaches and shipping. The environmental cost would extend beyond the cargo owner.
Insurance and liability
Marine insurers price the vessel, cargo, route and war risk. A transfer outside ordinary commercial patterns can require special approval or additional premiums. Coverage may depend on compliance with industry standards and government guidance.
If military forces are involved in protection, insurers will want to know whether that reduces attack risk or increases the chance of becoming a target. They will also examine who is liable if a government-directed movement contributes to a loss.
Opaque ownership and incomplete AIS data complicate underwriting. A peace agreement could lower premiums, but claims and investigations may continue long after traffic normalizes.
Sanctions and legal distinctions
Ship-to-ship transfers are lawful tools used throughout the energy industry. They have also been used to conceal sanctioned cargo origins. Legality depends on the oil, parties, documentation, location and applicable restrictions.
Companies must verify ownership, bills of lading, cargo origin and counterparties. A wartime workaround should not become cover for sanctioned trade or false documentation.
Governments should publish guidance so legitimate operators know what is permitted and compliance officers can identify abuse.
The economic benefit
Every barrel moved through the network supported producer revenue and supplied refineries. The system likely prevented a more severe shortage and reduced pressure on prices.
It also imposed costs that buyers ultimately bear: extra charter time, transfer fees, security, insurance and operational delay. Those costs can be reflected in crude differentials and product prices even when benchmark oil falls.
The broader benefit was continuity. Refineries need predictable feedstock, and sudden loss can force costly shutdowns. A partial flow is economically valuable even if it is expensive.
Worker and crew risk
Merchant crews performed complex operations in a conflict zone. They faced fatigue, security threats and pressure to move quickly. Employers have a duty to provide training, rest and the right to stop unsafe work.
Seafarers should not be treated as invisible components of energy security. Governments and cargo owners should disclose safety arrangements and provide support after traumatic incidents.
Labor standards remain applicable during an emergency. Commercial urgency does not justify avoidable exposure.
Corporate disclosure should match the risk
Publicly traded producers, tanker companies and refiners may have material exposure to the network. Investors need to know whether operations changed costs, volumes, insurance or legal risk. Companies should disclose material effects without revealing details that would compromise security.
Accounting questions may include when cargo ownership transfers, how extra freight is allocated and whether delays trigger contract penalties. Disputes can arise if sellers claim delivery while oil remains on an intermediate vessel.
Clear documentation is also necessary for taxes, customs and sanctions screening. Emergency practices should not weaken the commercial record that follows each cargo.
Regional governments carry the coastal burden
Oman and the United Arab Emirates provide ports, waters and emergency capacity near the reported transfers. Their authorities must coordinate traffic, environmental response and port-state inspections while balancing commercial and security interests.
Local communities bear the risk of pollution and disruption. Desalination plants and fisheries are critical infrastructure. Governments should ensure that response plans include public notification and compensation mechanisms.
Regional cooperation can reduce duplicated patrols and conflicting instructions. It can also establish common rules for when AIS may be limited and how vessels report confidentially to authorities.
Could the peace framework end the system?
If the Strait of Hormuz reopens and remains secure, ordinary tanker routes are cheaper and faster. Exporters would have a strong incentive to reduce transfers.
Normalization will take time. Ships must be repositioned, ports must clear schedules and insurers must regain confidence. Some transfer capacity may remain active as a hedge until several weeks of safe transit establish reliability.
Governments may also preserve the infrastructure as a contingency. The war demonstrated the value of alternative export routes, and future planning is unlikely to assume that Hormuz will always remain open.
The operation may also influence future naval planning. Protecting commercial movement can deter attacks, but close military association can make civilian vessels appear connected to a belligerent. Rules of engagement and communication should minimize that risk.
What transparency should follow
When security permits, the United States and Gulf governments should explain the scale, authority and environmental safeguards of the operation. Commercial confidentiality may protect individual contracts, but public military involvement requires oversight.
Shipping data should be reconciled with official export totals. Any spills, accidents or injuries should be reported. Insurers and regulators should review whether reduced signaling and nighttime operations complied with safety rules.
Reuters' investigation provides a credible outline, not the final official record. The distinction between independently observed movements, source descriptions and government denials must remain clear.
An emergency system with lasting lessons
The transfer network showed how quickly governments and companies can improvise when a strategic route is disrupted. It also showed the cost of depending on one chokepoint.
Energy planners will examine pipelines, storage, alternative ports and reserve capacity. Environmental regulators will need standards for large-scale emergency transfers. Military officials will have to define the line between protecting commerce and directing it.
The preliminary peace framework may make the system unnecessary. It will not make its lessons disappear: resilience requires alternatives, and alternatives require transparency, safety and legal accountability. The public record should eventually show whether the emergency network prevented a larger economic shock without creating hidden environmental, military or financial liabilities that will be paid later by governments, coastal communities, crews, insurers or energy consumers far beyond the immediate Gulf region over a long period.
Additional Reporting By: Reuters; U.S. Central Command; U.S. Department of Defense; International Energy Agency; U.S. Energy Information Administration; International Maritime Organization; public vessel-tracking and satellite-analysis sources.