The future of Royal Navy mine hunting

The 13 Royal Navy mine countermeasures vessels (MCMV) that remain active are ageing ships but a series of ongoing incremental upgrades will ensure they are able to remain in service into the early 2030s. Here we examine some of the upgrades and a take an overview of the complex plans for the RN’s future mine hunting capability (and attempt to navigate the confusing set of associated acronyms!).

Mines are a cost-effective way an adversary can deny access to ports, anchorages, and offshore structures. Mines are an attractive asymmetric weapon, particularly for weaker naval powers, they can be laid relatively easily and the technology continues to develop. A few well-placed mines can have a potentially strategic impact, keeping a fleet in port, strangling commercial shipping or preventing an amphibious assault. A new generation of smart, autonomous mines will to complicate the hunter’s job further. Neutralising mines is slow and painstaking work that requires practice, preparation and the best tools available. The RN is still a world leader in this specialism and is working hard to keep at the forefront of developments. At any one time, a significant part of the RN’s mine warfare strength is devoted to the Persian Gulf, ready to counter the threat of Iranian-laid mines.

Doing the same with less

Despite the undiminishing threat from mines and underwater improvised explosive devices (UWIEDs), financial pressures have seen the MCMV force halved since 2000. Just 6 of the original 13 Hunt class are left in service after HMS Quorn and Atherstone were prematurely decommissioned in 2017. Under the 2015 SDSR plans, another Hunt is scheduled to go before 2025, leaving a total of just 12 MCMV. The Single Role Mine hunters (SRMH) of the Sandown class are down to 7 left in service of the original 12 built for the RN. Despite the cuts to MCMVs, personnel numbers in the Mine Warfare and Diving branches are now actually rising slightly for the first time since WWII.

The remaining Hunt class vessels which date from the 1980s have all recently completed a major upgrade package. Starting with HMS Chiddingfold in 2012, the main work consisted of fitting new gearboxes and propellers and an upgrade to the hydraulic bow thruster system. Two new Caterpillar C32 ACERT engines replaced the old Deltics and have already proven very much more reliable in service. Great care has been taken to minimise the magnetic and acoustic signature of the new commercial off-the-shelf engines, while the chilled water plants have been improved and mess decks refurbished. The Hunt class are also being fitted with an improved new degaussing system that neutralises their modest magnetic signature.

The SRMH are also having propulsion upgrades. The first ship to undergo the Sandown Volvo Generator Programme (SVGP) was HMS Bangor in 2014. The two Perkins CV8 diesel-generators are being replaced with more efficient Volvo Penta D13s.

A replacement for the NAUTIS MCM command-and-control system fitted to all the minehunters is under development. The new Ocean Reconnaissance Combat Architecture (ORCA) will be fitted between 2019-22. The glass reinforced plastic (GRP) hulls of the MCMVs have a life expectancy of about 60 years and require less maintenance than steel-hulled warships. With recent upgrades to propulsion and mine hunting equipment, there should be no problems operating these vessels well into the 2030s, provided they can survive continual rounds of funding cuts.

  • Sonar 2093 display (left), Sonar body schematic (Centre) and during manufacture (right). (Photos: Thales)

  • The Variable depth Sonar 2093 body being embarked into the stowage position on SRMH.

  • Mine Warfare Officer in the operations room of HMS Atherstone, Persian Gulf 2009.

  • HMS Bangor deploys Sea Fox remote mine disposal system, Persian Gulf, 2015.

  • HMS Brocklesby begins major upgrade in the Minor War Vessels Centre of Specialisation, Portsmouth, 2015. (Photo: BAE Systems)

  • HMS Chiddingfold receives her first replacement Caterpillar C32 ACERT Diesel engine.

  • HMS Grimsby Rosyth

    HMS Grimsby emerges from the shed and onto the ship-lift in Rosyth. looking immaculate after a six month £3.9m Support Period (Docking) in October 2012.

Sonar 2093

At present, searching using ship-mounted sonar is the primary way mines are located. In 2015 Thales UK was awarded a £33.5M contract to deliver the Sonar 2093 Capability Sustainment Programme (CSP). This will increase sensitivity and definition of the sonar, using wideband pulse compression technology, improving its performance in detecting low signature mines. HMS Grimsby was the first of the SRMH to receive the ST2093 CSP and has been conducting trials this year, with the system formally accepted into service in August 2018.

Sonar 2093 was developed in the 1980s and is a multifrequency variable-depth sonar capable of search and classification operations down to depths of about 200 metres. The receiver and transmitter are lowered below the ship by cable so it can penetrate oceanic temperature layers. Broadly speaking, the SMRH are deployed in deeper waters while the Hunt class work in shallower areas, utilising their Type 2193 hull-mounted sonar which has very good definition up to about 80m depth. The ST2093 CSP will help the SRMH match the Hunt’s performance but in deeper waters.

MAS to defeat the mine

In May 2018 the first unmanned minesweeping system was accepted by the RN. The ATLAS Remote Combined Influence Minesweeping System (ARCIMS) uses towed Coil Auxiliary Boats (CABs) that simulate acoustic or magnetic signatures of ships in order to trigger mines or confirm none are present.

By 2022 there should be an established Maritime Autonomous Systems (MAS) based route survey and mine sweep / destroy capability in UK waters. Route survey is gathering seabed data for shipping lanes in advance, making it easier to spot newly laid mines. This is especially important in areas where the seafloor is very uneven with lots of Non-Mine, mine-like Bottom Objects (NOMBO) where it is easier for a potential adversary to lay and disguise mines. Route surveys of the entrances to key ports and naval bases is an important and ongoing requirement.

  • Atlas Electronik ARCIMS offers a variety of modules for detection and classification of submarines, mines and underwater objects. They can be operated fully autonomously, by remote control or be manned. Some of these capabilities will ultimately be delivered by the MMCM programme. (Images: AEUK)

  • ARCIMS (ATLAS Remote Combined Influence Minesweeping System) is an 11-meter long platform that can carry a payload of 4 tonnes. Water jet propulsion offers a top speed of up to 40 knots or around 15 knots with minesweeping gear in the water. Pictured here with the Northrop Grumman AQS-24 Synthetic Aperture minehunting sonar. The RN has two of these Vessels RNL Hazard (delivered 2014) and RNL Hussar.

  • The Halcyon C-Sweep USV jointly developed by ASV Global and Thales UK. Displacing over 8 tonnes with a range of over 230nm, it can achieve a top speed of 25 knots with a full payload. Pictured here with a Remote Operated Vehicle (ROV). (Photo: Thales)

  • ASV Halcyon II “Apollo” has greater efficiency, stability and an increased payload capacity over the Halcyon I. (Photo: via MASTT)

  • ARCIMS and Halcyon seen together during Exercise unmanned Warrior in 2016. The success of this technology demonstration exercise gave confidence for the RN to develop initial UK-based autonomous MCM capability (delivered under ‘Project Wilton’).

It is unclear if there will be funding for the Hunt class MCMVs to have major modifications to their quarterdeck so they can launch, recover and secure an 8-tonne USV and its payload, which would offer a world-wide capability. From 2020, it is expected the MCMVs will at least begin to be fitted with command facilities for controlling MAS, even if USVs cannot be embarked on board.


The Maritime Autonomous Systems Trails and Training unit (MASTT) is a small Portsmouth-based team tasked with testing and developing autonomous MCM systems on behalf of the MHC Project Team. The work done by this unit is building RN experience with MAS and will help and define future technical solutions and costs. MASTT were involved in the trials of ARCIMS prior to its acceptance in May and will continue to test the system well into next year. They have previously conducted autonomous USV launch and recovery trials using the Remus 600 UUV and various ROVs and collect data on navigational accuracy, and mine detection probability. Trials are conducted from a variety of locations; Falmouth, Portland, or the ranges at the British Underwater Test and Evaluation Centre (BUTEC) in Scotland. MASTT personnel also embarked in HMS Enterprise during her deployment as the Command Ship for NATO Mine Countermeasures Group 2 in 2017 and developed procedures for launching, recovering and operating the REMUS 600 UUV.

The Royal Navy Mining Unit (RNMU) is integrated into MASTT. The RN, perhaps unwisely, dispensed with its own offensive mine-laying capability long ago but and the mining unit is responsible for laying and recovering dummy mine shapes for training and trials purposes in UK waters. (You can follow the work of MAAST on Twitter: @MASTT12 )

Mmmm… MMCM

The Maritime Mine Countermeasures (MCMM) project is an ambitious collaborative effort with the French to use a variety of autonomous systems to dispose of mines. Based on boats built by ASV, it will be capable of operations up to 30 miles away from controllers in the Portable Operations Centre (POC). The system is complex and will potentially integrate the USVs, UUVs, a mothership, data centres, the POC and use satellite communications. Theoretically, a controller in the UK could conduct a minehunting operation in the Northern Gulf using MAS launched from the mothership 30 miles away from the minefield.

The MMCM concept (image: Thales)

A consortium led by Thales Underwater Systems and BAE Systems and including ECA (France) and ASV, Wood & Douglas and SAAB (UK) were awarded the contract in 2016. The MMCM system is in a demonstration and assessment phase until 2024, the French Navy and Royal Navy will each be provided for a system for two years of evaluation and testing. If successful, further contract awards would be made for the production phase, ready for initial operating capability around 2028.

The MHC programme – goodbye MCMVs

The Mine Countermeasures and Hydrographic Capability (MHC) project is a 10-year, multi-faceted assessment to decide exactly how the existing MCMV and Hydrographic survey ships will be replaced. In broad terms the expectation is that mine warfare in the 2030s will not be conducted by GRP-hulled specialist minehunters. The intention is to almost remove the human from the minefield entirely and use unmanned off-board systems (OBS). There will almost certainly be steel-hulled mine warfare ‘motherships’ to deploy this capability but procurement is some way off, expected between 2026 – 2033. They could be cheap second-hand merchant conversions such as oil rig support ships. A sizable working deck for launching and recovery is the primary requirement above basic sea keeping and habitability. Alternatively, the RN could consider dual purpose platforms such as BMT’s Venari-85 hybrid OPV/Minehunter. The Type 26 and Type 31e frigates will have a mission bay that can embark a mine hunting package of OBS, offering another potential platform for delivery. In some instances, there may be no need for a ship at all. The new way of minehunting can be done using MAS controlled from ashore using containerised command modules.

The current planning for the MHC programme appears to offer a flexible, incremental procurement strategy. Dividing the project into stand-alone items reduces technological risk and the size of individual investment decisions. The various USV, UUV and UAVs, together with their control and transport systems should deliver a coherent set of capabilities to defeat all kinds of sea mines in different environments. Instead of buying a few expensive MCMVs, investment will be made in a lot of different small modules and capability packages. The technology is evolving fast and there is flexibility to bring forward or defer purchases, depending on the maturity and effectiveness of each solution. This seems is a sensible policy but there is a greater potential vulnerability to ‘salami slicing’ cuts than that already experienced by the much-reduced MCMV fleet. Deferring the purchase of a few unmanned boats is politically a lot easier than axing a minehunter. Let us hope the MHC programme, primarily in the shape of the MCMM project, is able to deliver the full suite of mine countermeasures systems and important elements are not lost along the way.

Replacement of the two very successful Echo class Survey Vessel – Hydrographic Oceanographic (SVHOs) are also part of the MHC project. Their successors may also follow the simple/cheap mothership concept but with a greater reliance on OBS such as oceanographic gliders, UAVs and other MAS.

  • More than just a minehunter, HMS Hurworth shadows the Russian ship Yuri Ivanov, through the English Channel, August 2018.

  • The BMT Venari-85 OPV-Minehunter hybrid concept.

  • SD Northen River is operated by Serco Marine Services and is under contract to support RN trials and training, she can also embark the NATO Submarine Rescue System (NSRS). Vessel of similar design may be ideal potential MCM motherships.

  • HMS Ledbury and Blyth escorted by HMS Monmouth in the Northern Arabian Gulf, 2017.

  • HMS Middleton and Chiddingfold on exercise in the Gulf of Oman, 2010.

  • HMS Brocklesby on NATO duty in the Mediterranean Sea, 2010.

  • HMS Pembroke returns to her homeport of Faslane with family and friends on board after 3 years in the Gulf, April 2015.

  • Ex-HMS Atherstone awaits her fate in Portsmouth, August 2018. The MoD has yet to dispose of any GRP MCMVs by scrapping or recycling. Those disposed of so far have either been sold to foreign navies or are static training vessels. Prototype GRP minehunter, HMS Wilton serves as a yacht club HQ in Essex. (Photo: Steve Wenham)

A suite of unmanned systems should ultimately be a cheaper and safer way to counter mines than current solutions. There should be a lower manpower requirement and no need for expensive and highly specialised MCMVs but it is important that the RN manages to procure the sufficient motherships needed to carry the MAS to wherever they are needed in the world. No matter how effective unmanned systems may become, there may still be occasions when the complexity of the underwater situation demands intervention from a diver. Delivering divers and their equipment to the scene will still be a consideration.

The Hunt and Sandown class vessels have a wider utility beyond mine hunting for general patrol duties. In a very recent example, HMS Hurworth was employed to shadow Russian warships transiting the English Channel. Both HMS Echo and Enterprise have conducted lengthy deployments in the Mediterranean conducting maritime security and migrant patrols along with their core hydrographic work. These vessels also provide an important platform in the development of young officers, for whom an MCMV will probably be their first major sea going-command opportunity. There are also some personnel who tend to thrive in the close-knit MCM community in a way that they might not amongst the larger ships companies of major warships. Clearly, the phasing out of MCMVs and SVHOs will need careful consideration and the case for hybrid multi-role vessels perhaps makes a lot of sense.