Most tankers in Hormuz stop broadcasting location as conflicting claims cloud navigation

The ships have stopped saying who they are. Between August 1 and August 19, 112 hulls carrying crude, LPG and LNG passed through the Strait of Hormuz; only 21 openly used Iran's coastal route, and just two took the Omani route Washington insists on.

The other 89, more than 80 percent, went dark or sailed lanes nobody can confirm, according to Al Jazeera citing Kpler data on August 20. So the strait is open, but off the record: Donald Trump calls it open and under American control, Tehran declares it closed to ships that have not asked permission, and the US Navy blockades Iran-linked vessels all at once, with both sides making claims that cannot survive the autumn, as Al Jazeera reported on August 20.

At stake are incompatible goals. Iran wants all hulls to hug its coast past Larak and Qeshm Islands, both to collect leverage from the traffic and to let sanctioned cargo slip into Iranian ports. Washington wants ships on the southern Omani route under naval protection to show the waterway works without Tehran. Oman wants to be paid as host and nearly struck a management deal with Iran before Trump threatened military action to stop it, as reported by Al Jazeera on August 20. Shipowners, caught in between, want above all to avoid being the next missile story.

The numbers justify their fear. ADNOC disclosed this month that fifteen of its vessels have been attacked by missiles or drones since late February, killing one crew member and wounding twenty, Al Jazeera reported, quoting ADNOC's statement on August 20.

In July, the US fired Hellfire missiles at an oil tanker heading for Kharg Island after it ignored warnings, and on August 11 a Navy helicopter fired two more at the Panama-flagged Vela Nova for trying to run the blockade of Iranian ports, according to Al Jazeera on August 20. Transponder signals reveal to both militaries exactly where a ship is and which rules it is breaking, so operators have decided silence is the safest armor.

Marine insurers now price war-risk cover for a Hormuz transit at 7.5 percent to 12.5 percent of a vessel's value per voyage, based on Ajel English reporting Gulf marine insurance sources on August 19.

The immediate trigger was the collapse of the truce paperwork. The 60-day window opened by the June 17 memorandum expired on August 17 with no successor agreement and no open diplomatic channel, and weekly transits recorded by Lloyd's List Intelligence fell to 73 in the week of August 10-16 from 91 the week before, compared to a pre-war baseline near 130 a day, according to Global Energy Flow tracker on Day 175, citing Lloyd's List Intelligence, August 22.

Since the strait closed in early March, both sides have bombed ships they accuse of breaking rules, teaching every owner that switching off the transponder is the lesson. Al Jazeera reported that darkness spread because it worked, not because it was ordered.

Kpler's audit of crude tonnage shows the retreat into silence is nearly complete: 72 of 84 crude-laden tankers transiting since July 7, or 86 percent, sailed dark, mostly through the UN-sanctioned Omani corridor, per Global Energy Flow tracker citing Kpler on August 22. Some blacked-out crossings are Gulf states quietly moving oil – including Saudi, Iraqi, and Kuwaiti cargoes doing ship-to-ship transfers outside the strait so the receiving vessel, not the dark ship, appears at the destination port, according to energy researcher Marc Ayoub as quoted by Al Jazeera on August 20. Others are Iranian barrels laundered through Oman, documents redrawn so the cargo appears Omani before reaching market, reported by Al Jazeera on August 20. The method suits both smugglers and national oil companies, making it impossible for tracking firms to distinguish them.

The 1980s Tanker War

The historic model is the Tanker War of the 1980s, when Iranian and Iraqi attacks in these waters pushed Kuwait's fleet to reflag under the American banner and sail with Navy escort under Operation Earnest Will. That episode ended with more visibility: flagged convoys, announced schedules, and insurers able to name the risk they were covering. Now the movement has reversed, toward erasure, because neither navy can escort today's traffic volume and neither belligerent wants flows verified, just routed.

The counter-case exists: even during years of burning tankers, oil kept moving and prices eventually settled, but those tankers stayed visible. Today they cross in silence, and what cannot be seen cannot be confirmed safe.

Paying and Profiting

Asian refiners buying Gulf crude now pay a visibility premium twice. Increased freight and war-risk surcharges, and wider discounts demanded for barrels whose origin and volume remain uncertified. The oil market pays in volatility: Brent settled around $93.40 on Friday, up more than 5 percent on the week, on a supply picture that official trackers admit they cannot fully observe, according to Global Energy Flow tracker on August 22.

Those holding verified physical intelligence profit. Satellite firms selling dark-hull detection, ship-to-ship transfer brokers off Muscat and Fujairah who take a cut of every invisible barrel, and traders with port agents on both Gulf coasts who know what AIS does not reveal. The retail oil ETF holder has no such edge but absorbs all the volatility.

Safety Without Sight

The main consequence is safety, not commerce. When six in ten ships broadcast nothing, collision avoidance, search-and-rescue and de-mining lose their eyes; the central deep-water channel still carries roughly 80 mines that will take 40 to 50 days to clear when agreement comes, as reported by Global Energy Flow tracker on August 22. Washington plans an "economic D-day" sanctions package for Monday, August 24, aimed at banks, shipping registries, and smuggling networks, which will push still more traffic into darkness rather than back onto the charts, Global Energy Flow tracker reported on August 22. Each enforcement action inside a blackout teaches owners how to disappear more effectively.

The key confirmation would be Lloyd's List Intelligence weekly transits dropping below 60 while Brent moves past $100 on unverifiable flows. The break would be an enforced corridor deal—either the Iran-Oman arrangement revived or a US-escorted convoy—that returns named, insured hulls to the daylight route, with the dark-share dropping below a quarter of transits within weeks.

The burden falls on the twenty-person crews who navigate the most dangerous fifty miles of water with their radios off, with one crewman already dead and twenty wounded among ADNOC's fleet.

The numbers force an uncomfortable judgment. The world's most powerful navy controls the strait on paper, but it is Tehran's missiles that frighten captains, and the true movement of a fifth of global oil is now known only to those who sail it.