The Hormuz shipping crisis in numbers

The Strait of Hormuz has become a floating patchwork of cargos, registries and declared identities – but in war, what a ship claims to be may be up for negotiation.

Data shared with AGBI by maritime intelligence company Pole Star Global captures 3,208 vessels still signalling their presence in and around the chokepoint on March 20.

Thousands of bulk carriers, crude and oil products tankers, container ships, tugs and general cargo have clustered in the Persian Gulf. 

Together, they represent billions of dollars’ worth of commodities, including chemicals, metals and vehicles as well as oil and gas.

These graphics break down the fleet by type and status sailing under some of the world’s best-known registries, including Panama, Liberia, the Marshall Islands and the UAE.

It resembles a League of Nations at sea. But in the conflict environment, that comes with a warning label. These charts show vessels with their automatic identification system (AIS) switched on – transponders that broadcast their position, identity, course and destination.

Yet the system is only as reliable as the data being fed into it. Iran’s so-called shadow fleet, for example, often sails off-grid.

Visibility can degrade in an instant, according to Pole Star Global.

Saleem Khan, the company’s chief data and analytics officer, told AGBI that around one in 10 vessels operating in the Gulf are showing “anomalous” AIS behaviour, including spoofing, electronic interference and transponder deactivation.

That makes this the best available picture of what ships are declaring themselves to be – not necessarily a definitive guide to who owns, controls or even where they are really going.

The same caution applies to the flag on the stern. It does not reflect ownership, Pole Star said. A vessel registered in Panama or Singapore may be owned, controlled or commercially linked to interests elsewhere in the world.

Many ships sail under a so-called flag of convenience, meaning their registry does not necessarily reflect ownership or control.

Khan said many vessels were now in effect sailing with “forged passports at sea”.

“Some are changing destination fields mid-voyage to broadcast things like ‘China owner’, effectively signalling to the Islamic Revolutionary Guard Corps that they are friendly and should be let through.”

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The risks are not just commercial. Very large crude carriers typically move at 13 knots (15mph) through the chokepoint, forcing crews and operators to weigh whether to risk the contested waterway at all.

Pole Star Global says there have been at least 29 incidents in the Gulf, from ships being sunk to vessels set ablaze. At least a dozen merchant mariners have been killed. 

On March 31 Iran attacked a fully loaded crude oil tanker off Dubai. Trying to navigate the 21-mile stretch of water between Iran and Oman has left crews, in Khan’s words, as “sitting ducks”.

Graphics by Concetta Sidoti and Joel Barrick