Unmanned Underwater Systems
THOMAS WITHINGTON
© 2010 FrontLine Defence (Vol 7, No 5)

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Naval mines may be perceived as an antiquated weapon which brought destruction to ports and coastal areas during the Second World War, but reality is quite different. Underwater mines remain a potent threat in this era of asymmetric warfare. It offers a cheap weapon, sometimes costing as little as $1, 500, which can inflict millions of dollars’ worth of damage on a naval vessel or commercial ship. Witness the effect of Iraqi mines on the U.S. Navy’s USS Princeton Ticonderoga-class cruiser and the USS Tripoli Iwo Jima-class amphibious support ship during the 1991 Persian Gulf War. Both hit mines and suffered crew casualties and significant damage during the conflict. The French Navy alone pulls over 50 tonnes of old world war two ordnance out of the sea every year and a report from the Russian Emergencies Ministry last week indicates that over 150,000 sea mines and other explosives from World War Two still litter the Baltic Sea. For a nation or an insurgent organization anxious to close their coastline or littoral waters to naval shipping, the mine is an attractive weapon. Moreover, mine clearance often requires the skills of dedicated underwater demolition experts who perform the painstaking and highly dangerous work of making such ordnance safe.

For a nation (or insurgent organization for that matter) anxious to close their coastline or littoral waters to naval shipping, the mine is an attractive weapon on many levels. Moreover, mine clearance often requires the skills of dedicated underwater demolition experts who perform the painstaking and highly dangerous work of making such ordnance safe.
 
Decades after the invention of the modern naval mine by American engineer David Bushnell during the American War of Independence, it is no surprise that such mines present a continuing risk to shipping around the world. Taking the human out of the mine disposal equation has become an increasingly important con sideration in this day of robotic expertise. As has been the case on land, vis-à-vis Improvised Explosive Devices (IEDs), robotics in various forms have come to the aid of navies around the world when dealing with the mine menace. This threat not only includes ordnance that navies may face in future hostilities, but also the detritus of conflicts past in the form of unexploded World War II naval mines.
 
It is no surprise that, since the invention of the modern naval mine by the American engineer David Bushnell during the American War of Independence, taking human beings out of the disposal equation has become an increasingly important consideration. As has been the case on land, vis-à-vis IEDs, robotics in various forms have come to the aid of navies around the world when dealing with the mine menace. This not only includes ordnance that navies may face in future hostilities, but also the detritus of conflicts past, in the form of unexploded World War II naval mines.
 
Fortunately, a range of Unmanned Underwater Vehicles (UUVs) are available which can remotely deal with such mines at a safe distance without placing a person in harm’s way. As it looks to the future, Maritime Command has a range of UUV products available for the future modernization of its anti-mine warfare capabilities.
 
The two challenges of mine warfare are to locate the ordnance and then cause its destruction.
 
Help is at hand from Atlas Elektronik’s Sea Otter Mk II UUV. In late September, the company announced its successful demonstration of a Synthetic Aperture Sonar. This sonar technology can penetrate the underwater murk to provide an image of what maybe on the sea bed in almost photographic quality. It can even show shadows around an object, allowing mine clearance experts to determine whether they are seeing a mine or a shipping container which has fallen from a cargo vessel, for example.
 
 
Sea Otter (Atlas Elektronik)
 
Another unit from Atlas Elektronik is the Sea Fox, which comes equipped with a sonar, television cameras and searchlights. The destruction of the mine is achieved by the 1.5 kilogram (3.3 lb) shaped charge carried by the UUV. The Sea Fox is available in several variants including the Sea Fox-A which is an autonomous design, without a tether, that is connected to a surface vessel for its command and control. The Sea Fox-A comes equipped with the integral sonar, TV cameras and lights. The Sea Fox-C adds ordnance and sensors, whereas the Sea Fox-1 lacks the shaped charge and has been designed for training. Sea Fox has been acquired by the Royal British Navy and the Deutsche Marine (German Navy) and several other navies around the world.
 
Another European company, ECA of France has emerged as a leading force in the development and production of UUVs for mine warfare. ECA produces a number of UUVs and claims a host of navies around the world as its customers; International Submarine Engineering of British Columbia is ECA’s agent in Canada. Carrying television cameras, advanced sonar and search lights, ECA’s Alister can be used not only for mine warfare, but also for general reconnaissance below the ocean. With the Alister’s 20-hour endurance, operators can make a thorough search under the water and on the sea bed for mines. In fact, this UUV can work at depths of up to 300 metres (984 feet) and can travel at speeds of eight knots (14 kilometres per hour).
 
Joining Alister in ECA’s catalogue is the K-Ster, which is designed as a ‘one-shot’ UUV for mine countermeasures work and is equipped with an explosive warhead that can be tilted towards a mine to ensure that the blast is directed in such a way as to ensure the ordnance’s destruction. A searchlight and built-in sonar allow the craft to detect the mine while a fibre optic link transmits pictures from the K-Ster’s video cameras back to operators who can trigger the explosives once the mine is located. The UUV is able to perform its mission at depths of up to 300 metres (984 feet), although a version of the craft is available which can perform the same mission at depths in excess of 600 m (1,968 feet).
 
Explosive charges are also used by ECA’s PAP (Poisson Auto-Propulsed/Self-Propelled Fish); the first of which entered service in 1975. Low-light television cameras and sonar allow the PAP to locate the mines which can then be destroyed using its integral 100 kilogram (220 lb) charge. Alternatively, rather than using its own warhead, the PAP can carry a remote-controlled mine destruction charge, allowing the PAP to swim out to the mine, place the explosive near the ordnance, and be recovered to the ship before the detonation is performed.
 
ECA has also collaborated with Thales on the Asemar autonomous underwater vehicle, along with IXSEA, a French-based multinational company producing inertial navigation systems, and several academic institutions. Asemar is essentially a next-generation multi-role unmanned submarine which can perform general surveillance of underwater areas and the sea bed, or look for specific objects such as submerged mines. The advantage of this design for Canada is that this vehicle can effectively perform a number of roles using one platform, thus saving the procurement costs of having to purchase two UUVs; one to perform general undersea surveillance, and another dedicated to the mine warfare mission. Moreover, the Asemar operates without a tether providing impressive freedom of movement and reducing the amount of support equipment such as cable winches that a mother ship requires on its deck to operate a UUV.
 
Another multi-mission option is Saab’s Double Eagle. This remotely-operated underwater vehicle uses a tether and is designed for flexibility of missions. The rationale behind the Double Eagle design was to provide a modular unit that would easily accept new payloads. This was intended to make the craft ‘future proof’ to the extent that it could accept more advanced payloads as and when they are developed, removing the need for a navy to acquire a new UUV every time an advance in sonar or underwater electro-optics is achieved. To this end, the craft has a number of configurations, including the ROV-M mine warfare capability which adds a mine disposal charge and a sonar. Meanwhile, the ROV-S configuration allows the craft to be used for general mine-hunting and to sweep an area in front of a task group for mines. Furthermore, the SAROV configuration removes the craft’s tether and adds an autonomous capability.
 
Like ECA’s PAP, Kongsberg also uses explosives in their Minesniper product, which been acquired for mine countermeasures by the Armada Española (Spanish Navy). The standard warhead in the Minesniper is a shaped charge designed for mines with so-called ‘insensitive munitions’ which are built to withstand impacts, and fire to prevent accidental detonation. With the shaped charge, Minesniper sends a high energy beam into the mine, piercing the outer armour and triggering the munition. Using Kongsberg’s patented navigation technique, the vehicle is guided towards the target using the MCM sonar or proprietary acoustic positioning system. The system processes the sonar image and guides the vehicle automatically to the target. Operator intervention is only needed in the very last phase of the mission for manual control, inspection and disposal of the mine. Minesniper is able to attack anchored and floating mines as well as either partially or totally buried mines.
 
Products such as these are designed to be operated from a surface ship. Boeing, on the other hand, has developed the AN/BLQ-11 Long Term Mine Reconnaissance System. The design of the AN/BLQ-11 is such that it can be deployed from a submarine’s torpedo tube to search the surrounding locale for bottom contact and tethered mines. Bottom contact mines are placed on the sea bed and are designed to be triggered by deep draft vessels operating in shallow coastal waters. Tethered mines, meanwhile, float below the surface and are kept under the water by an anchor. Boeing’s product offers up to twelve hours’ endurance and, once ongoing testing is complete, the AN/BLQ-11 is expected to enter service with the US Navy as the world’s first submarine deployed UUV.
 
Boeing has a second option. After more than three years of use for oil and gas surveys in the Gulf of Mexico, Boeing has completed a full refurbishment of the Echo Ranger LDUUV for military purposes. With a re-machined frame structure, new motor windings and fin actuators, a new pressure vessel, adaptable hull penetrators and state-of-the-art computers, this 5.6m long, 127cm diameter workhorse is now demonstrating UUV utility for Navy long-endurance ISR and ASW missions. Echo Ranger boasts a 452kg payload capacity, COTS-based modularity, and proven autonomy.
 
 
Echo Ranger (Boeing)
 
BAE Systems has returned to the more familiar ‘one-shot’ approach with their Archerfish UUV which is designed as a single-shot mine clearance system.
 
Archerfish can be launched from a boat or from a helicopter when a suspected mine is detected. Once in the water, the UUV is guided to its quarry using fibre-optic cables. The UUV has a short-range sonar system to locate its target and can send back video pictures to its operators across the fibre optic cables. Highly manoeuvrable, Archerfish is able to navigate around a target to provide a detailed picture, allowing operators to ascertain exactly what type of mine they are confronting. When ready, a command is sent to Archerfish to detonate the mine using its warhead – this can be directed in such a way to ensure the maximum destructive effect.
 
Craft like the Archerfish or the Sea Otter certainly won’t make naval mine warfare obsolete; underwater mines will almost certainly retain their appeal as low cost ordnance giving ample ‘bang for the buck.’ However, for today’s governments, taking the human out of danger is a crucial factor. As Canadian Maritime Command contemplates how it will execute mine warfare defence in the future, these products offer several options in terms of unmanned technology that can be used to ensure that their own ships, and those of their allies, remain at low risk from mine attack.

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Thomas Withington is a defence journalist and writer based in France.
© FrontLine Defence 2010

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