Today's Minehunting Technology

Traditional minesweeping consumed resources of ships, men and materiel on a grand scale; a squadron of six or more sweepers, employing between two and five hundred sailors, could take several days to clear a minefield of (say) 40 mines; even longer if the trigger mechanisms were fitted with counters, requiring up to 20 passes before the mine would actuate/explode and adverse weather resulted in breakages and replacements of gear. This would not have been an unusual scenario at any time from 1916 up to the introduction of effective minehunting in the mid 1960’s.

The balance began to swing when reliable high definition sonar such as the Plessy 193 became available. Technology began to overtake seamanship in combatting naval mines, and  the need for precise navigation became even more acute, leading to exploitation of SATNAV and active rudders. Factors such as water temperature and salinity were imported from the world of SONAR and, as CCTV went underwater, visibility could become significant; murky waters ensured continued use of divers for the really tricky jobs …

The minehunting vessel illuminates the water column with its sonar and guides a workboat (Geminini dinghy) to a position vertically above the Mine Like Object and a diver descends to identify it.

If the object is considered to be a hazard to navigation, the GPS position is recorded and a diver returns with a demolition charge (Mine Disposal Weapon) to destroy or disable it.

Minehunting significantly reduces the risk to the crews of mine counter measures vessels, by enabling them to stay outside suspected dangerous waters and to investigate, classify, then dispose of, the threat of “Mine-Like Objects”, ideally from a safe distance. Current research aims to improve the economics of this concept by replacing the vessel that ventures into the minefield by an “intelligent remotely operated underwater vehicle” (ROV). Historical and marine researchers, the oil and gas industry, salvage engineers, hydrographers and treasure seekers began to take TV and mechanical grabs underwater in the mid-1960’s, so it was not surprising that this technology was soon also applied in the world of mine countermeasures.

Typical of the first generation of naval ROVs was the French PAP [Poisson Auto-Propulsé - self–propelled fish] which was used by several NATO navies, including the RN and USN, (pictured left, being launched by a Dutch minehunter) , and the German PINGUIN.

Second generation ROVs have even more capability, combining a greater variety of senor systems including video, sonar and magnetic anomaly detectors, with warheads that may be shaped charge or armour piercing.

The German SEAFOX (pictured right ) used by the RN and several other navies, COBRA and the Norwegian MINESNIPER are typical of this type of system; all remotely controlled from a mother ship via an umbilical, through which TV pictures, GPS positioning and environmental information may be sent to the ship’s Operations Room, which responds by sending manoeuvring instructions to the ROV.

One of the issues with minehunting is that it has to be conducted at low speed. typically 4-6 knots, so the minehunter becomes a target for the hostile forces that laid the mines. Current practice in the Gulf is to assign a frigate to cover the minehunting operation.

Miniaturisation of electronic components allows newer ROVs to carry a greater payload with greater capabilities and the accuracy of placing the explosive charge allows that, too, to be reduced (remember the bulk of the Mine Disposal Weapon employed by TON minehunters), all of which results in a decrease in the physical size of the ROV. These are typically now under two metres in length and weigh less than 40 kg. Range, speed and depth are also increasing. An ROV such as the French K-STER (below), also used by the Singapore Navy, can operate to greater than 3000 metres range, 200 metres depth, at six knots for several hours and is effective even in a tidal stream.

The next logical step is to remove the umbilical cable and to build into the ROV sufficient computer power that it can follow a pre-programmed mission profile, take video, sonar or magnetic readings as required, transmit this data to its mother ship and finally use GPS to find its own way home, having monitored how much battery power it has remaining.

REMUS, (Remote Environmental Monitoring System), is one such Autonomous Undersea Vehicle (AUV). It was first developed in the late 1990s for the Woods Hole Oceanographic Institute by Hydroid, a subsidiary of Kongsberg Maritime. It is reported to be in use by the U.S. Japanese & Polish navies for shallow water mine countermeasures and hydrographic reconnaissance . REMUS has been taken to the Gulf by the Royal Navy Maritime Autonomous Systems Trials Team (RN MASTT – photo courtesy of RN website ).

Improved capabilities in seabed mapping have civilian applications in environmental and archaeological surveys but the next step in military operations for an intelligent autonomous underwater vehicle is Intelligence, Surveillance & Reconnaissance.

From the same stable as K-Ster, the A9-M, is a small AUV with long endurance for stealthy special operations. Launched from the sea by a small boat or canoe, it is able to reach its target undetected and undertake reconnaissance of a harbour, beach, offshore installation or even a ship’s hull, by Side Scan Sonar and high definition video.

An ideal way to probe harbour defences and to record what has been discovered ! Research in Europe has tended to concentrate on operations in relatively shallow seas, perhaps because our MCM doctrine has been heavily influenced by the ground mine and our wide continental shelf. By contrast the USN is experimenting with using roboticdevices to counter buoyant mines, especially the deep laid variety (remember EDATS).

The Lockheed Martin system (photo below) operates just below the surface and deploysits own side scan sonar in a tethered pod (white device in the photo ). This 6-ton, 23-foot long monster is launched from the stern of a Littoral Combat Ship and driven through the suspected minefield by an operator on board the ship. Initial reports say it is proving cumbersome on trials. Its role is to identify mine like objects, so presumably other techniques are used to dispose of them.

Experiments are being conducted in Austria into the behaviour of “swarms” of unmanned underwater vehicles; half a dozen or more very small craft, each less than a metre long, and each equipped for a specific role, such as magnetic, video or sonar detection and able to communicate with each other via data links, so that they can act in concert to conduct a survey of say a hull, oil rig, harbour bottom or lock gate and then, maybe, place an explosive charge; think Exercise Awkward, with tadpoles ! The significant feature of the swarm is thatif one vehicle is damaged another can take over its role, automatically as they all share a command/nervous system,

The mission would be programmed into the shared data base of the swarm aboard a mother craft which itself might be a stealth vessel some miles offshore, or a commando unit closer to the scene.

IN April 2020 the Royal Navy declared the Automated Remote Control Influence Minesweeping System (ARCMIS) to be operational. The system has been designed and manufactured by Atlas Elektronik UK under a £13 million contract, signed in 2015, working with DE&S and the RN’s Maritime Autonomous Systems Trials Team (MASTT).

The Unmanned Surface Vehicle (USV) is controlled from ashore and utilises radar and GPS to enable it to detect and avoid other vessels and surface obstacles. The same technology directs the craft in the laps when clearing a minefield.

The USV tows three or more Coil Auxiliary Boats (CABs) which emit electronic signals to detonate acoustic and magnetic influence mines.

A variant can tow a buoyant magnetic cable, similar to the LL sweep of our time.   

The robot “tug” is 11 metres long, displaces ten tons, (akin to an inshore fishing vessel) and YES ! that is an Oropesa float acting as tail end marker – the technology of our era can still come in handy.

The modern sea mine is an even more devious device than the iron eggs and ground   mines equipped with  multiple triggers and ship counts of our day. Many have plastic bodies, shaped to resemble rocks on the sea bed, which do not respond to the searching sonar beam of the minehunter.

Most have micro-processor controlled trigger mechanisms – just think of the computing power of the chip in your digital watch or palm computer and envisage how it could be used for offensive purposes e.g. only trigger when the precise sound of QE (or a super tanker) doing 20 knots, plus appropriate magnetic signature, is detected.

Modern explosives are more powerful and compact than MINEX or TORPEX, enabling the devices to be made smaller but produce a bigger bang and, in place of a main charge, some even have the equivalent of an Exocet in a watertight tube, waiting for the signal to fly 20 km or more to the specific target. All of which are good reasons for letting automation undertake the dull, dirty and dangerous aspects of mine detection and   destruction and keep the sailor and his/her ship outside the minefield.

A complementary autonomous mine-hunting system is to be developed jointly with France, whereby the USV will deploy unmanned underwater vehicles (UUVs) and sonars to find and destroy mines. It is anticipated that Hunt class MCMVs may be modified to deploy two of the new USVs, although the timing is unclear.

ARCIMS will form part of the RN’s Mine CounterMeasures and Hydrographic capability (MHC) project and, since the components fit into ISO containers,  can be transported to the area of operations by land, sea or air.

The autonomous system could be deployed from a “mother ship”, but the precise form that will take is still far from decided. Potentially the mission bays of the Type 26 and Type 31 frigates or a hybrid OPV / minehunter could be utilised, along with auxiliaries or amphibious vessels. Whether the RN will ever again require dedicated minehunters is debatable.

In 2012 the MoD announced that unmanned systems will feature prominently in the RN’s new Type 26 frigate. “… Along with a UAV-compatible flight deck, the ship will have a flexible mission bay including a ramp to allow deployment of rigid-hulled inflatable boats, unmanned surface vehicles, or towed-array sonar. Unmanned naval systems extend the ship’s sensor range, provide persistent intelligence coverage, and reduce crew risks for certain missions such as mine-clearance …”

It is possible that the days of the dedicated mine countermeasures vessel may be coming to a close. It will probably not happen for some years, but a future generation of MCM specialists may find themselves aboard a steel or composite hulled, multifunctional, stealth mother ship with an ISO container load of intelligent unmanned underwater vehicles and instrumentation which link into an Action Information System shared between other ships and aircraft in a task force and gridded-in to a Maritime HQ ashore.

Let’s hope that Future Jack and Jenny may still occasionally be able to taste the salt sea spray and enjoy a good run ashore.