The Strait of Hormuz has been effectively closed for almost four weeks – throwing global oil markets into chaos – and there is no clear end in sight.
Iran’s threats and attacks on vessels in the Gulf have raised the risk of transit enough to stop almost all traffic through the narrow waterway, which is the main conduit for about 20% of the world’s oil and natural gas, plus fertilisers that help grow crops the world relies on.
As the energy crisis deepens, US President Donald Trump has touted diplomatic efforts to end the blockade, while also moving to deploy thousands more troops to the Middle East and looking into possible US Navy escorts for oil tankers.
But Iran still has the upper hand in many ways – in part because of its unconventional warfare methods, including cheap drones and sea mines, and in part because of its geography. Taken together, these two realities make it harder for the United States or others to defend vessels or to secure the strait militarily.
And it’s lucrative for Iran to retain control. Iranian officials have said they will continue charging fees for the safe passage of some tankers through the strait, after Lloyd’s List Intelligence released a report on March 23 saying at least two vessels had paid large sums to cross.
Why does the geography favor Iran?
The Strait of Hormuz is about 24 miles across at its narrowest point, according to the shipping analytics firm Vortexa. And almost all traffic goes through two main shipping lanes that are even more squeezed.
“It is described as a chokepoint for a good reason. There are supposedly a lot of chokepoints around the world. But you could argue that this is a uniquely challenging one, because there are no alternatives,” said Nick Childs, senior fellow for Naval Forces and Maritime Security at the International Institute for Strategic Studies (IISS).
Part of the challenge for vessels and any potential ship-escorting operations is that the room for maneuver is highly constricted.
“In the open ocean there is always the option of re-routing; in a chokepoint or narrow sea, that option is impossible,” said Kevin Rowlands, journal editor at the Royal United Services Institute think tank. “That means that Iran doesn’t necessarily need to seek out and find its targets. It can sit and wait.”
It effectively creates a “kill zone,” he said, in which the warning time for an attack can be mere seconds.
Not to mention, Iran has almost 1,000 miles of coastline, from which it can launch anti-ship missiles. Those missile batteries are mobile, making them harder to eliminate, and the long Gulf coastline means that Iran can attack well beyond the strait itself.
“On the northern, Iranian side, it isn’t a flat plain. There are hills, mountains, valleys, built-up areas and offshore islands. These all make detection of an incoming threat more difficult and make it easier for Iran to hide mobile weapons systems,” Rowlands, who is also the former head of the United Kingdom’s Royal Navy Strategic Studies Centre, told CNN in an email.
What threats do vessels face in the Strait of Hormuz?
Analysts say Iran’s capacity to inflict damage on commercial vessels through its array of offensive capabilities has been reduced since the war began.
“However, it is almost impossible to reduce the risk to zero, and we can expect ships to face a residual level of threat for some time to come from some or all of these systems,” Rowlands said.
Iran has deployed a multi-layered offensive strategy to control the strait
Iran’s strategy has effectively closed the Strait of Hormuz, and the US is considering naval operations to secure the waterway. Here are the biggest threats civilian vessels face in the strait.
The complex threats mean that any operation to escort vessels would likely need to go well beyond a traditional convoy of warships travelling ahead of and behind tankers, according to Rowlands.
“It is more likely that a naval mission will use a layered defense approach, with surveillance from satellites, patrol aircraft and aerial drones. Ships may take a specific route which has been cleared of mines,” he said.
The US has managed to degrade many of Iran’s conventional naval capabilities, Childs said. But the highest threat still comes from Iran’s unconventional arsenal, like drones, fast-attack small vessels and even unmanned boats that are filled with explosives.
“If the Iranians do decide to mine, you can roll those off the back of an otherwise innocent looking dhow (sailboat),” Childs told CNN. “Although the US has probably accounted for Iran’s major submarines, there are possibly still ‘midget submarines’ to have to think about,” he added, referring to small submarines that can operate in shallow waters.
Allies of the US including the UK, France and Bahrain, are also working to develop viable plans to safeguard international shipping in the waterway.
Where do things stand now?
Iran has attacked at least 19 vessels near the Strait of Hormuz, in the Persian Gulf and in the Gulf of Oman.
And analysts note that Iran doesn’t even have to destroy vessels to succeed in its goal of disrupting the global energy trade. As long as the threat remains sufficiently high, shipping companies are unlikely to take the risk of resuming transit. Some vessels with ties to Iran, China, India and Pakistan have made it through the strait, though.
Iran has said that “non-hostile vessels” may transit the strait if they coordinate with Iranian authorities. The Lloyd’s List Intelligence report said that at least 16 vessels have made it through, including one believed to have paid a $2 million fee, as well as several “zombie” tankers that used the false identities of dismantled vessels. CNN cannot independently verify the report.
Even if all tanker traffic restarts eventually, it will take time to clear the backlog: Nearly 2,000 vessels are trapped inside the Persian Gulf, according to the International Maritime Organization.
The Trump administration has been touting what it says is diplomatic progress. Iran, meanwhile, maintains it is not in negotiations with the US, although it has acknowledged an exchange of messages through mediators.
Trump’s talk of negotiations comes against a backdrop of thousands more US Marines and sailors heading towards the Middle East.
Two US officials told CNN earlier this week that the 11th Marine Expeditionary Unit and Boxer Amphibious Ready Group are on the way. And US officials previously told CNN that the Marine Expeditionary Unit (MEU) of the USS Tripoli assault ship was being sent to the Middle East, without revealing exactly where it would be deployed or what operations it would be used for.
Those MEUs typically have been used for missions like evacuations and amphibious operations that require ship-to-shore movements, such as raids and assaults. That has increased speculation about potential boots-on-the-ground operations, although the Trump administration has so far said it has ruled out ground operations in Iran.
Military analysts said the US might be banking on the fact that just bringing the USS Tripoli and other marine assets to the region to pose a threat might be enough to change Iran’s calculations.
Trump is also threatening to strike more sites related to Iran’s oil trade if it continues blocking the Strait of Hormuz. Last Friday, the US military hit military facilities on Kharg Island, which handles roughly 90% of the country’s crude exports. Sites related to the oil trade on the government-controlled island were not hit, but Trump has warned they could be next, which would present another escalation.
Credit: CNN
