Maritime Mine Counter Measures
Our Navies came out of the Second World War with quite an important inventory of minesweeping equipment and techniques. And that was necessary because minesweeping operations to clear mines in our waters went on until 1969. The last such operation was called “New Broom 2” and took place in 1969 in the German Bight on the Elbe – Texel route. It is only afterwards that “Shipping Insurance Companies” were prepared to cover ships sailing outside the Nemedri* routes in that area.
Again, during this operation, the limitations of the efficiency of influence mine sweeping were encountered: it proved to be impossible to determine the most effective technique against a given mine firing system and lack of detailed knowledge of the environment prevented the accurate prediction of the performance especially of acoustic and magnetic electrode minesweeping techniques. These limitations will in the nineties of last century lead to the “target simulation approach” in influence sweeping.
Another handicap was the poor navigation accuracy combined with a very low speed and difficult manoeuvrability of the large gears some 500-yard-long and 200 yards wide. The standard deviation of navigational errors, that was never really accurately measured, was estimated at up to 200 yards, this as well for visual, for radar as for Decca navigation. The inaccuracy in navigation resulted in thousand or more yards wide channels to be cleared.
Mechanical sweeping of moored mines had found a satisfactory solution using techniques derived from those used in the fishing world. Yet during the Korean War a number of minesweepers were lost due to moored contact mines. That is the reason why most of the Mutual Defence Aid Program (MDAP) minesweepers of the Coastal and Ocean types delivered to the West European Navies by the United States in the fifties were equipped with a sonar: a “moored mine avoidance sonar”.
It is with those moored mine avoidance sonars on board of the Ocean Minesweepers that the first dedicated mine hunting was carried out: detection and classification by clustering method and identification and neutralisation by conning run and divers. A great number of runs in a thousand-yard-wide channel through a supposed minefield resulted in clusters of encountered sonar contacts, the existence of the cluster lead to the classification “mine like”. The subsequent conning run for the identification and neutralisation by divers was hindered by the poor performance of the sonar who had the greatest difficulties to detect and track the sonar reflector under the dingy of the divers.
The late sixties saw the advent of the first purpose transformed British minehunter HMS Shoulton around the 193 sonar and the first purpose build French minehunter FNS Circe with the DUBM20B. In the early seventies, the Belgian and Italian Navies were installing US SQQ 14 VDS sonars on board Ocean Minesweepers.
Mine hunting coming to maturity resulted in a number of new types of hunters such as the CMT (FR, NL, BE), the Lerici (IT), the Sundown (UK), the Frankenthal (GE), the Oksøy (NO) and others. All these ships were equipped with double frequency sonars for the detection and the classification and with remotely controlled underwater vehicles for the identification and the neutralization of detected/classified mines. Data bases of preparatory route survey on the planned war routes was supposed to assist future mine hunting operations but also this was handicapped by poor navigation accuracy and by the limited range of the classification sonars.
Minesweepers and minehunters all operated in the supposed minefield. A large effort is made to protect them by reducing their magnetic and their acoustic signature and minehunters stay out of the danger radius of the mine they are dealing with. Still it remains highly dangerous. The German Navy therefore developed in the late seventies the Troika System with up to four unmanned radio controlled minesweeping drones (Seehund) operated from a mothership that stayed outside the danger area. The mothership cannot take the drones on board and for delicate manoeuvres, such as leaving and entering port, a three-man crew was put on board.
Over a quarter of a century ago the arrival of worldwide satellite navigation provided an acceptable solution to the navigation challenge. It remains to be seen however, if accurate satnav will always be available in times of war or conflict.
During the Cold War, there was a three-MNC Concept of Maritime Operations and each Major Nato Commander had his own General Defence Plan. As far as Maritime Mine Counter Measures were concerned the idea was to detect minefields by intelligence or reconnaissance MCM operations and to clear channels through them within 72 hours after disclosure.
The enormous amount of civil off-shore activities and the development of unmanned vehicles and their tools, the improved electric power storage capacity, the possibility of mass data collection, the improved acoustic imaging, the possibilities of light detection and ranging (Lidar) in certain areas, the improved accuracy of also underwater navigation, the overall more accurate knowledge of the underwater environment and the resulting better overall situation awareness brings the MCM community to reconsider its overall concept of operations.
It has now become possible to take the human out of the minefield without penalizing the deployability, by having all the tools on board of a single ship with sufficient space speed and range. To detect, classify, identify and neutralize in a single action can produce the desired effect of reduced mine threat in a shorter time. Remotely controlled target simulation sweeping can take care of buried or difficult to detect mines. Acquiring, storing, transferring, integrating and handling huge quantities of environmental data increases the quality of the planning and of the evaluation, this clearly is a task where the Mine Warfare Centre of Excellence has a role to play and where overall coastal security is to benefit from.
Having control of the North Atlantic and its approaches being of vital importance also in the future, it is up to the Navies and the Firms here represented to define and to realize those new solutions, to increase the performance of the capabilities, to reduce cost and weight of new equipment and to install trust and confidence in those new unmanned approaches.