Should the Royal Navy rebuild its minelaying capability?

The RN currently has no stock of sea mines or dedicated minelaying platforms. Here we look at whether regenerating this capability would be worthwhile and the options available.

Background

At the end of the Cold War, the UK rapidly divested its stock of sea mines has not possessed any since 1992 (unless there is an undeclared ‘black’ stock). Mines have traditionally been seen as a weapon of weaker naval powers and also have some legal and ethical restraints that complicate their use. Successive British governments since the 1960s have been lukewarm about the use of both sea and land mines by UK forces. With a diminishing threat in the post-Cold War period there seemed to be little need for mines to protect the UK mainland or for offensive use against adversaries.

The RN’s last minelayer was HMS Abdiel, built in the late 1960s. Officially designated as an ‘exercise minelayer’ she was primarily used to train RN personnel in the art and for laying practice mines for MCMVs to hunt or sweep. The very dated RN instructional video below filmed on board Abdiel gives an insight into the techniques used to lay tethered mines and the basic nature of the ship.

Despite her training ship designation, it was intended Abdiel could be used to lay live mines in wartime. She also was deployed in support of mine clearance operations around the Suez Canal following the Yom Kippur War (1974-75). Her final task was ‘supporting’ modern minehunters in the Persian Gulf (1987-88) but as an old vessel with very limited facilities, she was more often the ship needing the support. This rather unique ship was decommissioned and sold for scrap on her return to the UK in the summer of 1988 and was not replaced.

The news that Australia plans to invest the equivalent of £500 Million in new sea mines raises an interesting question about whether the RN should also consider re-acquiring these weapons. The RN has always maintained healthy mine countermeasures forces and a developed concept of operations for defending UK ports and harbours and strategic overseas waterways. Since countering mines is much more difficult and expensive than laying them, perhaps the UK should not content itself with being on the side of asymmetric disadvantage and develop its own mine-laying abilities as part of a broad deterrence posture. It should be noted that any new mine warfare capability would be likely to look very different to the legacy weapons and methods of the HMS Abdiel’s era.

Essentially there are 4 main factors. (1) The global situation is now much changed and there is undoubtedly a greater threat to the UK mainland itself as well as wider maritime interests. (2) There is a particular threat to undersea infrastructure that could be partially countered by mines or mine-like weapons. (3) A new generation of smart mines and autonomous delivery methods offers new ways to employ mines. (4) Acquisition of a small stock of sophisticated mines could be a relatively quick and low-cost route to increase RN lethality.

Matching peers

The Russian submarine threat is obviously of the most immediate concern to the RN, but mines could potentially be used to help defend Pacific allies from Chinese naval activity or counter Iranian forces in the Persian Gulf.

The best way to win a battle is to not have to fight at all. If your adversary can be bottled up in harbour at a critical time by the threat of inexpensive mines, it is a far more effective and cheaper way to achieve victory. For example, UUVs could be used to penetrate the territorial waters of adversaries to lay small numbers of mines near naval bases designed to target submarines or warships. Restricting operations from the Russian Northern Fleet bases on the Kola peninsula or the Baltic Fleet bases in Kaliningrad and St Petersburg would be a huge strategic advantage. The RN makes substantial mine countermeasures efforts in the Firth of Clyde and approaches to Faslane in response to known Russin submarine-minelaying capabilities.

Precise numbers are hard to come by but it should be noted that the Russian navy is thought to have around 250,000 mines of various vintages while the Iranians have somewhere between 3-6,000. The Chinese have an active offensive mining development programme and are thought to possess at least 80,000 consisting of up to 30 types, including sophisticated encapsulated torpedo mines and rising mines.

Seabed warfare

The battle for supremacy in the underwater domain is now in a period of very rapid change as the world becomes ever-more reliant on subsea pipes and cables while developments in maritime autonomous systems open up new vectors for attack and defence. Growing concerns about the vulnerability of seabed infrastructure demand solutions for protecting these critical assets.

Increased vigilance and fleets of patrolling UUVs maybe the first line of defence but mines could play a deterrent role. Potentially a CAPTOR-type mine could be developed that releases a small torpedo to attack any unrecognised UUV or ROV detected in the vicinity. It would not be possible to protect the thousands of miles of cables and pipework but knowing that these ‘sentry’ mines had been deployed in a few places would create uncertainty in the minds of adversaries. Should a more open conflict erupt, there could also be a case for laying less sophisticated tethered mines along particularly vulnerable parts of the network.

New technology

New technology has blurred the line between the dumb sea mine and sophisticated torpedoes and smart weapons that can discriminate precisely between targets and be activated from long ranges. More intelligent mines can be delivered in much smaller numbers for precise and calibrated effects in specific locations in contrast to the barrages of tethered and floating mines laid in past conflicts.

The RN does not need dedicated minelaying vessels. The SSNs have a theoretical minelaying capability but XLUUVs are a much lower risk and stealthier solution for covert and sensitive missions. Where stealth is less important, containerised minelaying solutions are being developed that can be secured to the deck and dispense mines over the stern. Alternatively, merchant ‘vessels of opportunity’ or motherships (such as RFA Stirling Castle) could be employed to lay mines directly or launch XLUUVs for more covert tasking. The Type 26 frigates also have a mission bay and a handling system, potentially capable of launching and recovering XLUUVS up to 15 tonnes.

The RN has already started on the path towards XLUUV operations with the Manta and Cetus programmes. The first or second generation of these platforms is very unlikely to be equipped to launch torpedoes due to the difficulties of keeping humans in the decision-making loop. Their ISR capabilities are obvious but if they are to be used for more offensive purposes, they would appear to be very well suited to minelaying which can be precisely preprogrammed before they begin the mission. XLUUV payloads are limited to a small number of mines but to some extent, this is offset by their ability to lay mines with precision in areas that would be inaccessible or too high risk for an SSN or a surface vessel.

Options

UK domestic mine manufacturing capability disappeared sometime ago, with the last being the Stonefish series manufactured by BAe in the 1990s but only for export. If the RN was looking to acquire a modest stock of mines quickly, then off-the-shelf weapons from overseas would probably the most viable option. There are a few European sea mine manufacturers, notably Rheinmetall Italia, SAES Spain and DA Group of Finland. In the US good progress is being made regenerating its offensive mine warfare capability primarily as part of its Pacific tilt to contain the Chinese threat.

The US Hammerhead programme is similar to the CAPTOR mine originally developed during the Cold War. It is primarily an anti-submarine weapon with a sensor that can detect and classify target. Sitting in an upright tube on the seabed, when it detects a valid target, a Mk-54 lightweight torpedo is released that rapidly rises to attack the submarine or underwater vehicle. Hammerhead is being developed specifically for deployment by the USN’s Orca XLUUV.

Summary

The RN frequently talks about increasing it’s lethality but progress in this direction is very slow. Although minelaying is often perceived as ‘playing dirty’, acquisition of a small stock of sea mines would provide a genuine increase in offensive power, quickly and at relatively low cost, requiring minimal supporting infrastructure and training. This does not to be a £half billion procurement on a par with the Australian initiative, but would demand resources which would inevitably come at the expense of something else. Some will take the view that we should focus fully on ensuring the new autonomous mine countermeasures systems are effective but a small investment in Hammerhead or equivalent to equip future RN XUUVs would be an affordable first step.