How US could clear mines from Strait of Hormuz

As the United States embarks on clearing mines from the Strait of Hormuz, it could draw on an arsenal of drones, explosive-laden robots and helicopters to reduce risks, though de-mining crews could still be vulnerable to Iranian attacks. The US is trying to secure the strait from mines as part of efforts to end Iran's disruption of shipping, which has severely curbed global energy ⁠supplies since the US and Israel launched strikes against Iran at the end of February.

But while the US can draw on modernised technology to remotely check for and remove mines, ⁠clearing a strategic waterway such as the Strait of Hormuz will still be a slow, multi-step process, former naval officers and industry ‌specialists say. The US military said over the weekend it had ​started the mine-clearing operation, sending two warships through the strait, but offered few details about the equipment involved. It said on Saturday that additional forces, including underwater drones, would join the effort in the coming days. Iran had recently deployed about a dozen mines in the Strait of Hormuz, Reuters reported last month, citing sources familiar with the matter. It is not publicly known where mines may have been laid.

US President Donald Trump said over the weekend that all of Iran’s minelaying ships had been sunk. But there is a risk Tehran could deploy additional devices, ​some specialists said. Mine warfare is effective because the devices ⁠are cheap, are costly to clear and “even the threat of a minefield is enough to stop ships, especially commercial ships," said Jon Pentreath, a retired British navy rear admiral who is now a consultant.

MODERNIZING MINESWEEPING

Traditionally, the US Navy relied on manned minesweeping ships that physically entered minefields, using sonars to locate the devices and mechanical gear dragged behind the vessel to clear explosives, sometimes supported by human divers. Much of that aging fleet has been retired.

They are being replaced by lighter vessels ⁠known as littoral combat ships, which ‌carry modern mine-hunting equipment such as semi-autonomous surface and underwater drones as well as remote-controlled robots that enable crews to distance themselves from the minefield. The navy has three of these in deployment. Two of those ships were undergoing maintenance in Singapore, a senior US official told Reuters ‌in late March. At the time, the US minesweeping capacity in the Middle East included unmanned undersea vehicles, four of the traditional Avenger-class vessels, helicopters and divers, according to the official. The US Navy did not respond to a ⁠comment request on the mine-clearing capability it currently has in the Middle East. US Central Command declined to provide further details.

Tehran is believed to possess several types of maritime mines, former naval officials and other specialists say. These include bottom mines that ‌rest on the seabed and detonate when ships pass above, tethered mines that are anchored but float closer to the surface, drifting mines that ‌move freely on the water, and limpet mines that attach directly to a ship’s hull. The US operation will likely involve searching for mines using ‌unmanned surface and underwater vehicles equipped with sensors. Once a mine-like object is detected, the data is typically transferred to crews operating outside the minefield, who identify the ‌device. They then determine how it should be neutralized.

The Navy’s search capability now includes sonar-mounted unmanned surface and undersea vehicles, as well as helicopters that are used to spot mines near the surface, former naval officials say. To destroy mines, the Navy can deploy systems such as the torpedo-shaped Archerfish, a remotely operated device about 2 metres long that carries an explosive charge and transmits video back to operators ⁠via cable, according to its ⁠manufacturer, BAE Systems. Designed to be expendable, it costs tens of thousands of dollars.

The US could also use unmanned boats towing mine-sweeping sleds that trigger detonations or gather mines, said Bryan Clark, a retired US naval officer and senior fellow at the Hudson Institute. Human divers are also sometimes used, including for intelligence gathering, specialists say.

SLOW PROCESS

Clearing the strait could take two or three weeks, Clark said, and Iranian attacks on mine-clearing crews could slow the process and raise risks. As a result, he said, the US military may deploy defensive measures like ships and airborne drones to defend crews and equipment.

“Finding and destroying mines is very time consuming,” US Admiral Daryl Caudle, chief of naval operations, said in March. That leaves mine-clearing capability “vulnerable,” he added.

New technologies are being developed to speed up mine clearance, particularly through advances in sensors used for detection, specialists say. French technology ​and defence group Thales says its latest sonar can scan a suspected mine from three different angles in one pass, a process that typically requires multiple sweeps.

Advances in ​artificial intelligence are also enabling more data analysis to be carried out ​onboard unmanned vessels.

Longer term, the ambition is to deploy groups of unmanned systems that can search for, identify and destroy mines, rather than it being a multi-step process.

“That doesn’t exist today,” said Mark Bock, a retired US Navy ​captain who is now vice president of business development at Thales’ US Navy business. “But it is what all nations are trying to achieve now.