Naval Mine Warfare

Naval mines can have an impact far beyond their cost. Europe Editor Dim Jones brushes up on the topic during a visit to MCM1 at Faslane.

The first practical naval mine was invented by an American, David Bushnell, for use against the British in the American War of Independence. It was a watertight keg filled with gunpowder, which was floated toward the enemy, and detonated by a sparking mechanism if it struck a ship. It was used on the Delaware River as a drift mine, and was regarded as unethical. Arguably, however, naval mine warfare goes back many more centuries, in that the ‘Greek Fire’ of the 7th century, and the fireships of medieval times shared many of the same characteristics. Mine warfare played a prominent part in both World Wars and, despite advances in technology since then, many of the principles of both offensive and defensive mine warfare remain very much the same.

Two Squadrons

The Royal Navy’s Mine Countermeasures force comprises two squadrons, MCM1, equipped with seven Sandown Class minehunters and based at Faslane on the Clyde, and MCM2, with eight Hunt Class vessels, based at Portsmouth. Two of each class are currently permanently based in Bahrain. The Hunt Class ships first entered service in the 80s and, at 750t displacement and 60m long, they are the largest warships constructed from Glass-Reinforced Plastic (GRP), and carry a crew of 44. They were originally designed for both minesweeping and minehunting; however, minesweeping procedures – essentially the deployment of a towed device, either a non-magnetic wire sweep with an explosive cutting device, or an acoustic/magnetic influence sweep – required the ships to enter a potential minefield and, with the sweep deployed, restricted the manoeuvrability of the ship, thereby rendering it vulnerable. Advances in location, identification and destruction techniques have now rendered these hazards unnecessary: the sweep gear was withdrawn in 2005, although the ships remain equipped, and the sweep systems could be reinstalled within 30 days. The Hunt Class’s principal mine detection sensor is the Thales 2193 hull-mounted wide-band sonar, which can detect and classify an object the size of a football at a range of up to 1000m. For closer identification and disposal of mines, the ships are equipped with Seafox disposable Remotely Operated Vehicles (ROV), which replaced the much larger PAP-104 vehicles between 2007 and 2009. The crew also includes a team of mine clearance divers. The Hunt Class vessels are fitted with the BAE Systems Nautis 3 combat management system, which controls navigation, mine detection, classification, remote disposal and, through the main propulsion system and bow-thrusters, ship manoeuvring and position-keeping.

The seven Sandown Class vessels are some 10 years younger, and somewhat smaller at 600t displacement and 53m, with a crew of 40. They are also built almost entirely of non-magnetic materials, including a GRP hull and the extensive use of Seeman Composites Resin Infusion Moulding Process (SCRIMP) in the superstructure. This requirement for low-magnetic and acoustic signature pervades all parts of the ship’s construction and equipment, and comes at a cost – as witnessed by the £200 toaster in the galley! Sandown Class vessels are also equipped with the Nautis 3 and Seafox, and with the Ship Position Control System (SPCS), which can be operated either manually or automatically, and can maintain the ship’s position over the seabed – ‘hovering’ – to within five metres. The main armament on both classes is a DS30B 30mm Oerlikon gun, with a fire rate of 650 rounds per minute and, for self-defence, miniguns and Barricade decoy launchers, which can dispense IR decoys and chaff. The sonar equipment is the Thales Type 2093 multifunction system, which can be deployed from a well in the hull with any one of five arrays for mine detection and classification. The difference in the sonar fit renders the Hunt Class more suitable for shallow-water operations, and the Sandown for deeper work – although paradoxically the larger Hunt is better in rough weather.

Specialists

Mine warfare is part of the General Service branch of the RN, and ratings will remain mine warfare specialists throughout their careers, graduating from their basic training at HMS Collingwood, Fareham, as Able Seamen MW, and being streamed to either Sandown or Hunt at that point. Those selected as Clearance Divers will complete several diving courses at Horsea Island (Portsmouth), Portland and Oban in west Scotland, learning their trade using various equipments in different conditions and at varying depths (down to 60m), by day and night. The training culminates in a 14-week tri-service Explosive Ordnance Disposal (EOD) course, followed by a three-week Naval Weapons module. The personal diving gear weighs 60kg, and uses a mix of helium (rather than nitrogen) and oxygen, which allows for cleaning and rebreathing, giving an endurance of about two hours. A typical diving team will consist of: a Petty Officer, who acts as the Mixed-Gas supervisor; a Leading Diver, who is the Air Supervisor; and three or four Able Seaman divers, who do most of the actual diving. The MCMVs are all equipped with decompression chambers. The divers’ specialist capabilities are not required all the time, so they all have other jobs on board, both in peacetime and on operations.

Officers qualify as either Mine Warfare or Mine Warfare and Clearance Diving Officers, and will progress through a series of posts such Navigator, Operations Officer (OPS), responsible for ‘fighting’ the ship, and Executive Officer (XO), who runs the ship for the CO. At an appropriate point, they will complete the Principal Warfare Officer (PWO) course, following which they will rejoin the mainstream surface warfare branch as senior Lieutenants or junior Lieutenant-Commanders and be eligible for appointments in the destroyer (DD) or Frigate (FF) fleets. They may then either return to the MW branch, in which some might feel that their career and promotion prospects would be limited (although, in compensation, mine clearance divers receive specialist pay), or remain in the surface fleet, where there will be wider career opportunities. The CO of an MCMV will not necessarily be a Mine Warfare specialist, but his OPS will be.

The MCM force is somewhat unique in the RN, in that it operates constituted crews, who are not tied to a particular hull; a crew will stay together for about 18 months, during which time it will generally serve a six-month detachment in the Gulf, thus obviating the costly and inefficient rotation of hulls through the Gulf theatre. The crew live and eat on board, even when in port; the accommodation is less than palatial, and GRP is not particularly good in hot and humid conditions, so 6 months at a time is probably enough! During the crew cycle, there will be individual postings in and out, to accommodate personal circumstances and career management.

Mines

So what of the ‘enemy’. There are two basic types of mine: ‘moored’, which are tethered to the sea bed at a set height, and include the ‘spiky ball’ of film fame; and ‘ground’ which are free-lying on the sea bed, and are generally ‘influence mines’. A third variety, the floating mine is less common, although employed by Saddam Hussein during the Iran-Iraq War, equipped with a timer detonator. There are various triggering mechanisms: contact; acoustic; magnetic; and pressure (triggered by the bow wave of a vessel). Mines are often deployed covertly from the torpedo tubes of submarines, and these will conform to what appears to be an international convention on tube diameter of 21 inches. Mines are very easy to make, and have not changed much from WWII, other than in refinements, such as anti-handling devices. They are now better engineered, although it should be noted that the German mines of WWII were exceptionally well built from first-class materials, which results in them being found to this day still in excellent condition, while their Allied equivalents have long since rusted away. The Soviets made a lot of mines, and supplied their friends, so many potential adversaries could be expected to possess Russian stock, or home-grown variants.

A miniGun dinner engages the aggressor, while HMS Middleton takes evasive action

A typical scenario for MCM operations could be clearance of an area as a precursor to an amphibious landing. Depending on the task, MCMVs can operate alone or in teams, and their activities will be controlled by the Commander Task Group (CTG)’s MW battle staff, who will be either embarked (for instance, in a Royal Fleet Auxiliary (RFA)) or ashore, as circumstances dictate. MCMVs are not best-equipped against attack, and will require force protection, especially in terms of air superiority, again provided by ship- or shore-based assets. The MCMV will locate, and initially classify, mines using active sonar, and then maintain station on them, while deploying either an ROV (Seafox) or diver(s). The disposable ROV, made by Atlas Elektronik is small (1.3m) and, at only 40kg, can easily be manhandled, thus eliminating the need for heavy lifting gear. It is controlled from the MCMV’s Ops Room by fibre-optic, and is guided to a point downstream of the mine, whereupon it uses its high-frequency relocation sonar to find the mine, and echo-sounder and CCTV camera to positively identify it. Four independent reversible motors give high manoeuvrability, and ensure precise positioning for employment of a shaped charge warhead, either through contact or by manual detonation.

Should undersea conditions or the need for more positive identification require it, the MCMV can deploy a diver, who can quickly identify the mine or take measurements (using known personal dimensions such as hand’s breadth, length of forearm), report back to the Ops Room and, if necessary, place a fuse-operated charge next to the mine which will later be detonated at a safe distance from the dive boat, once the diver is clear.

Sea Training

During every 18-month crew rotation, and prior to proceeding on operations, the crew will undergo a period of Operational Sea Training (OST), conducted under the supervision of Flag Officer Seat Training (FOST)’s staff. The FOST staff responsible for the MCMV force is located at HMNB Clyde at Faslane, where I embarked in HMS Middleton, a Hunt Class vessel, to undergo a ‘Train for Mission’ evaluation exercise in company with HMS Pembroke, a Sandown Class MCMV. This was in Week two of a four-week training period, but represented a major milestone in the training programme. It was conducted in much the same way as (although on a smaller scale than) the ‘Thursday Wars’ which I observed aboard HMS Dauntless out of Devonport (see MS&T 2-2011), in that the ship was accompanied by a team of Sea-Riders (FOST evaluating staff), including ‘Wreckers’, whose task was to create realistic scenarios for evaluation. The ship’s company was Crew 8, and many notices around the ship bore witness to the ethos which the CO, Lt Cdr Andy Brown, wishes to engender in them.

The exercise started with the ship in port, at a state of readiness in Transition to War (TTW), and being tasked to proceed to an exercise area in the Firth of Clyde. The conditions, it has to be said, were not the stuff of the Arctic Convoys; it was a sunny day, with light winds, and the Clyde was like a millpond. Nevertheless, it is an exceptionally busy piece of water, with many vessels – ferries, fishing boats and pleasure craft – competing for limited space; this would have kept the bridge staff busy under normal circumstances – and these were not going to remain normal for long! As is standard practice, many of the crew had action-stations employment well-removed from their day jobs, such as the cooks, who became the medical staff. Real incidents can be distinguished from exercise injects by the use of the codeword ‘Safeguard’. While HMS Middleton was providing force protection for HMS Pembroke, both ships were shadowed by the aptly-named HMS Tracker, an Archer Class Patrol Vessel acting as an aggressor, which used the cover of other shipping to approach before attacking. There ensued a period of eye-watering manoeuvring, as the two MCMVs defended themselves with main and secondary armament and small arms, until the threat was beaten off. Next up was the air threat, often unavoidably simulated but, in this case, provided live by a DA20 aircraft of FR Aviation (see MS&T 6-2013). Its repeated attacks provided the Wreckers with the opportunity to generate all manner of incidents, including fire, flooding, structural damage, equipment failures, casualties, and smoke on the bridge, causing it to be evacuated, and the ship controlled from standby positions. Even the eventual return to port was not without incident, as we came under attack from an RPG7-armed ‘terrorist’ boat, thinly disguised as a harbour tug, a scenario which replicates a possible scenario in the Gulf. This had been a general - rather than MW-specific - exercise; for MCM2, these are conducted, at a generally less frenetic pace, from Campbeltown on the Mull of Kintyre, which affords deeper water than the Clyde.

Relatively little use is made of simulation during MW training. For the bridge crew, the generic Pathfinder bridge simulator is used to simulate entry and exit from various ports, under all conditions of weather, sea state and light. There is also a MW simulator at HMS Collingwood, which emulates the MCMV’s Ops Room environment, and can replicate both hull-mounted and towed-body sonar, although its simulation of Seafox is limited. As regards live exercises, MCMVs often work in teams, and UK-based ships operate regularly with the Navies of other NATO nations. As we go to press, The US 5th Fleet is gearing up to host the International Mine Countermeasures Exercise (IMCMEX) in the waterways of the Middle East; this is the largest exercise of its kind in the world, and will involve around 6,500 service personnel from nations spanning six continents. A possible exercise scenario could be a threat to the free passage of shipping through the Straits of Hormuz, a threat which certain nations in the area are quite capable of mounting. Crew 8 will arrive in the Gulf too late to participate, as they are scheduled to take over HMS Chiddingfold in November.

Thus far, this article has confined itself to the RN’s mine-hunting capabilities. As regards mine-laying, the official UK Government policy is that: ‘The Royal Navy does not have any mine stocks and has not had since 1992. Notwithstanding this, the United Kingdom retains the capability to lay mines and continues research into mine exploitation. Practice mines, used for exercises, continue to be laid in order to retain the necessary skills (Hansard).’ Indeed, during my observation of the ‘Perisher’ (the RN’s Submarine Commander’s Course, see MS&T 4-2012), minelaying was among the tactical exercise objectives. BAE Systems manufacture Stonefish, an influence mine deployable from fixed-wing aircraft, helicopters, surface vessels and submarines, and using acoustic, magnetic and pressure sensors. There are four versions, Warstock, Drill, Assessment and Exercise.

A Fire crew prepares to tackle a blaze below decks. In the background (left) is a Seafox ROV, and (right) the divers' decompression chamber.

What of the future for MW? It would be easy to say that, in view of the lack of change in the threat, it will be ‘more of the same’. However, increased use of more capable ROVs would reduce the hazard to both MCMV and divers, although the safety record of the latter is already exemplary. Autonomous vehicles could survey programmed areas, returning with detailed reports to be decoded on board; this would obviate the requirement for the MCMV to go near a minefield, and would eliminate the need for costly GRP construction and low-signature engineering. More esoterically, the US, arguably, has never been ‘into’ MW in the same structured way as the RN, is not tied down by set paradigms, and is, therefore, more open to innovations, such as the Marine Mammal Program, which trains marine mammals, principally bottle-nose dolphins and California sealions, to perform military tasks, including ship and harbour protection and mine detection and clearance.

Meanwhile, one thing is certain; as long as there are mines, there will have to be mine countermeasures.