How mines could tighten Iran’s Gulf chokehold

It is a frightening scenario for US naval strategists and shipping companies: that an embattled and embittered Iran could seek to enforce its chokehold on the strategic Strait of Hormuz by seeding its narrow waters with deadly mines.

Many mine warfare experts believe Tehran has already done just that by deploying a handful of seabed devices that it could turn on at any time to threaten shipping on a route that carries a fifth of global seaborne trade.

“It is almost certain,” said Mr Farzin Nadimi, an expert on Iran’s naval forces at the Washington Institute for Near East Policy. “They are waiting to be activated.”

Activating such weapons using cables attached to shore installations or acoustic signals – or deploying other less sophisticated models from Iran’s stock of more than 6,000 naval mines – could pose a huge challenge to a US navy that has few effective countermeasures.

There is no confirmation of Iranian mine deployment and some experts are unsure whether Tehran has done so. But officials in Washington have told US media that Iran might have already positioned up to a dozen mines in the Gulf, which at its narrowest point is just 21 nautical miles wide.

The US said on March 12 it had destroyed or damaged over 30 Iranian minelaying vessels, but Tehran could still deploy mines from surviving attack vessels or by firing them from submarines’ torpedo tubes.

Simple mines can be dumped into the sea off trawlers, cargo ships and even the wooden dhows that ply the Gulf. It is sometimes only possible to spot a ship rolling mines overboard by listening for loud splashes in its wake.

“There is a huge asymmetry between mine laying and mine clearing, because one is much easier than the other,” said Mr Tom Shugart, a former submarine commander at the Center for a New American Security.

Iran’s mine stocks include modern designs capable of detonating in response to ships’ specific acoustic, magnetic and other signatures, as well as crude contact mines. Some are designed to float freely, others are moored by cable or sit directly on the seabed. Iran also has limpet mines that could potentially be attached to passing tankers from speedboats.

Dr Steven Wills, a former officer on a US minesweeper now at the Center for Maritime Strategy, said dead sheep thrown away by livestock ships, whose legs stick out of the water when they bloat, could sometimes be mistaken for mines by lookouts.

“This is potentially a hard mission,” he said.

Adding to the challenge, the US has allowed its anti-mine capabilities to atrophy for decades and is in the process of retiring its wooden-hulled Avenger-class ships, the navy’s last remaining dedicated minesweepers. 

Replacing them are three littoral combat ships in the region that have taken on the role of hunting mines. Unlike dedicated vessels which can move quickly into minefields, these new ships work mine-by-mine by using lasers on helicopters and unmanned vehicles that bounce sonar off their surroundings. “It will be a slow and laborious process,” Dr Wills said.

During the Iran-Iraq war, an Iranian moored contact mine severely damaged the guided missile frigate USS Samuel Roberts in 1988.

But Washington has for decades dedicated less than 1 per cent of its naval budget to mine warfare, despite mines being responsible for almost 80 per cent of US warships sunk or disabled since 1945 and over 75 per cent of its naval casualties since 1950. European nations now have more developed mine-warfare capabilities than the US.

“This may all be about to come home to roost,” Mr Shugart said.

It would also be the first time the US has had to deal with mines at sea while under fire since the 1950-53 Korean war.

“It is hard to imagine effective or safe mine clearance operations while the larger war is going on,” said Dr Caitlin Talmadge at the Massachusetts Institute of Technology. “This is not a mission you want to be doing in the middle of a shooting war.” 

Dr Talmadge said a determined Iranian effort to mine the strait could put Washington under pressure to end the war quickly or find itself needing to deploy special forces to eliminate shore-based threats to its mine hunting and escort vessels.

Establishing a passageway through a minefield would require extended effort. Vessels doing the clearing or subsequently using the swept routes would be highly vulnerable as they moved slowly and predictably along them, making it much easier for Iran to target them with missiles and drones, said Dr Scott Savitz, a senior engineer at the think-tank Rand.

Dr Savitz, who has previously advised the US on mine warfare, said even a small number of mines would force both commercial traffic and military traffic to consider how much risk they were willing to take.

“You can have an effective minefield with zero mines, if others perceive it as posing a substantial threat,” he said. Financial Times