Transiting the Strait of Hormuz remains one of the most dangerous voyages a ship can make, and despite assistance from the US Navy, vessels are still being attacked. The threat comes from the air as well as from below the surface.
Steve Cameron, a former merchant navy officer who now works as a maritime consultant, says crossing the strait requires agreement between a captain and the crew to accept the risk, war risk insurance, and a final decision by the master. Missiles and drones are the visible danger; mines may be lurking underwater. “If you’re a captain, you’d like to see evidence mines aren’t present,” Cameron says.
Modern mines rest on the seabed and detonate when they detect an acoustic or magnetic signal, triggering a pressure wave that will break the keel of a passing vessel. Others can rise through shallow waters or float, or be powered toward a target. The technology itself is neither difficult nor costly, but the mere threat can stop a tanker fleet from sailing.
“Mines are a very cheap way of waging a naval war, as the Royal Navy is acutely aware,” says Ian McFarlane, a naval architect with the French defense group Thales who knows mine warfare well.
Taking sailors out of the danger zone
Finding sea mines has traditionally been the job of specialist mine-hunting vessels with crews of around 80 sailors. An increasing share of the work is now done by autonomous systems monitored from the shore, which may need only about 20 personnel working in shifts on land. With the recruitment and retention problems facing NATO navies, these highly portable robot systems have become especially attractive.
The technology has been under development for two decades. During the 2003 Iraq war, the US Navy searched the seabed with a torpedo-shaped robot called the Remus 100. Sweeping with sonar and operating down to around 100ft, the little machines spared divers a difficult and dangerous task.
Newer systems tested in the Gulf
The latest conflict in the Gulf is putting far more capable systems to the test. The US military is sparing with details about its mine-hunting craft, but glimpses have emerged. In early September, Iranian forces hauled an uncrewed US autonomous sub out of the waters of the Strait of Hormuz. The Pentagon claimed the robot, an Extra Large Uncrewed Underwater Vehicle (XLUUV) built by US autonomous defense technology venture Anduril, was a malfunctioning older device carrying no classified equipment.
Whatever its mission, no sailors were imperiled. According to William Lupton, a naval analyst with Shephard Group, that outcome “was a drop in the ocean compared to having prisoners taken” — and that is part of the point of uncrewed vessels.
What happens when a robot is seized
NATO navies are reluctant to discuss what happens if an uncrewed vessel is captured, but computer drives can be wiped or destroyed remotely by various means. Such a step may have taken place inside the circuit boards of the XLUUV seized by Iran.
Sonar, AI and a 3D picture of the seabed
Autonomous technology is being embraced by forces around the world. Cooperation between Thales, the Royal Navy and France’s Marine Nationale has produced a robot motor launch. The Thales Uncrewed Surface Vehicle (USV) is packed with sensors programmed to detect mines using sonar originally developed for the oil and gas industries. It tows a 5m long rectangular box, similar to a large torpedo, that takes a high-resolution look at the seabed and builds a 3D picture refined by artificial intelligence. The newest mines are designed to blend into their surroundings, and the software flags anything that looks like one.
Autonomous systems are cheaper than conventional minehunters, and they can be deployed by air together with containerized control centers.
A hybrid fleet that shares data
Steve Prest, an associate fellow at the RUSI defense think tank, introduced uncrewed mine hunting into the Royal Navy and became its first fleet robotics officer in 2014. “There is a bunch of ways to look for a mine using robot boats or robot subs, and while you can’t prove the negative, that no mines are there, you can reduce the risk,” he says. US robot minehunters, he notes, can either blow up a mine or simply mark the spot as somewhere to avoid.
He expects the trend to widen. “We’ll see more use of autonomy but also the missions and capability will expand. And AI will be analysing data from those vessels on the spot as opposed to data being analysed when a drone returns.”
The Royal Navy recently announced its concept of a hybrid navy that mixes drones with conventional warships. For that vision to succeed, Prest argues, the fleet must operate as a single distributed force sharing data within what he calls a cognitive architecture. Robots only make a real difference as part of that scheme, and focusing on individual uncrewed assets is a mistake. “Uncrewed or autonomous vessels are not the operating system. They are applications running on it,” he says.
Fear of the unknown
Robots may be on the rise, but people remain central to what happens in the strait. Neil Roberts, who speaks for insurers at Lloyd’s of London on marine matters, says the psychological impact of the mine threat is inescapable, as is uncertainty over how many mines, if any, are actually out there. In his account, the US says it has cleared the Omani route and believes the mine threat is being managed, with shipments running at about 75% of pre-conflict levels.
Fear of the unknown is the most potent aspect of the sea mine threat, and robots are now the weapon of choice for confronting it.