Autonomous vessels replace crews in hazardous mine hunting operations

The deployment of uncrewed robotic systems is transforming the dangerous task of sea mine hunting, particularly in conflict zones such as the Strait of Hormuz. As traditional naval vessels face increasing risks from missiles, drones and submerged mines, defence forces are turning to autonomous technology to keep personnel out of harm’s way. These systems, which have been under development for two decades, are now being tested in active combat environments, offering a safer and often more cost-effective alternative to conventional mine-hunting ships that typically require crews of around 80 sailors.

Transiting the Strait of Hormuz remains one of the most perilous journeys for any vessel. Despite assistance from the US Navy, ships continue to face attacks, and the threat of mines lurks beneath the surface. Modern mines can rest on the seabed, detonating when they detect acoustic or magnetic signals, or they can float and be powered towards a target. The mere presence of these devices can halt tanker fleets, as the technology is inexpensive to deploy yet devastating in effect. Ian McFarlane of the French defence group Thales notes that mines represent a cheap method of waging naval war, a reality the Royal Navy is well aware of. To mitigate this risk, captains require evidence that mines are absent, a task traditionally performed by specialist vessels with large crews.

The shift towards autonomy is driven by both safety and recruitment challenges facing NATO navies. Autonomous systems can be monitored from shore, requiring only around 20 personnel working in shifts on land. This reduction in crew size is attractive given the difficulties in retaining naval personnel. The technology has evolved significantly since the 2003 Iraq war, when the US Navy used a torpedo-shaped robot called the Remus 100 to scan the seabed with sonar, sparing divers from dangerous tasks. Today, more capable systems are being employed in the Gulf, although the US military has been sparing with details about its specific mine-hunting craft.

A recent incident in early September highlighted the stakes involved when Iranian forces hauled an uncrewed US autonomous submersible out of the Strait of Hormuz. The Pentagon stated that the device, an Extra Large Uncrewed Underwater Vehicle from Anduril, was a malfunctioning older model with no classified equipment on board. William Lupton, a naval analyst with the Shephard Group, emphasised that while the capture was a setback, no sailors were imperilled, which he described as a significant advantage over taking prisoners. NATO navies are reportedly equipped with mechanisms to remotely wipe or destroy computer drives in such vessels to protect sensitive data, a measure that may have been employed in the seized XLUUV.

Collaboration between Thales, the Royal Navy and France’s Marine Nationale has produced the Thales Uncrewed Surface Vehicle, a robot motor launch packed with sensors. This system uses sonar technology originally developed for the oil and gas industry to detect mines. It tows a five-metre rectangular box that scans the seabed in high resolution, creating a three-dimensional picture refined by artificial intelligence. This software is designed to identify mines that are engineered to blend into their surroundings. Autonomous systems are not only cheaper than conventional minehunters but can also be deployed by air, along with containerised control centres.

Steve Prest, an associate fellow at the RUSI defence think tank and the Royal Navy’s first fleet robotics officer, argues that while robots cannot prove the absence of mines, they significantly reduce risk. He notes that US robot minehunters can either detonate mines or mark them for avoidance. Prest predicts that the use of autonomy will expand, with artificial intelligence analysing data on the spot rather than after the vessel returns. He advocates for a hybrid navy approach, where drones and conventional warships operate as a single distributed force sharing data through a cognitive architecture. Prest warns that focusing on individual uncrewed assets is a mistake, as they are applications running on a broader operating system rather than the system itself.

Despite the technological advancements, the human element remains critical. Neil Roberts, who speaks for insurers at Lloyd’s of London, points out that the psychological impact of the mine threat is inescapable, compounded by uncertainty over the number of mines present. The US claims to have cleared the Omani route and believes the threat is being managed, with shipments running at approximately 75 per cent of pre-conflict levels. The fear of the unknown remains the most potent aspect of the sea mine threat, and autonomous robots are increasingly becoming the primary tool used to confront that fear.