Tracking submarines

Robotic technology is making anti-submarine surveillance stealthier, cheaper, and a lot more effective — advances that are driving new naval tensions between China and the US. 

Last month, the US Navy announced plans to spend more than $220m on 18,000 new-generation sonobuoys — expendable air-launched underwater acoustic sensors — to help it detect, track and, if required, torpedo-attack enemy submarines. 

Leading weapons contractor, Lockheed Martin, meanwhile, has also recently contracted technology group Thales to supply 55 advanced anti-submarine dipping sonars, which can be deployed from helicopters, to be supplied to the navies of India, Greece and Denmark. 

Both contracts reflect the escalating commitment by navies around the world to invest in new, inexpensive, and operationally flexible, unmanned anti-submarine warfare technology. 

The US Navy already uses an extensive, and rapidly growing, range of robotic anti-submarine assets, including the CARINA undersea glider and the SeaGuardian aircraft — a drone that can link up remotely and electronically with surface warships and widely dispersed sonobuoys to execute long-range, over-the-horizon, guided-missile targeting. 

Earlier this year, the US Navy revealed details of yet another autonomous device, the Snakehead Large Displacement Unmanned Undersea Vehicle (LDUUV) — a long-endurance drone that can be deployed from the dry deck shelter of a nuclear-powered submarine. 

Chinese copies 

This determination by the US and western navies to push ahead with sophisticated robotic anti-submarine technology is known to be causing concern amongst China’s military elite.  

The country’s state-controlled national TV news channel recently broadcast footage of a US-built Wave Glider device said to have been found off the Chinese coast by local fishermen.  

Built by the Boeing subsidiary, Liquid Robotics, the Wave Glider is an autonomous surface platform, the size and shape of a surfboard, that trails a 26ft (8m) umbilical tether which can be fitted with specialist sensors for scientific research or intelligence gathering. 

The winged float beneath the Wave Glider (Credit: Liquid Robotics) 

China says it has also found several other types of unmanned marine drones and sensors in its waters, which, it believes, have been sent into its waters on secret military missions.  

The discovery of the Wave Glider has, however, inspired China’s own naval technologists, at the country’s Institute for Advanced Ocean Study in Qingdao, who are now reported to have developed two copied versions of the device — the Sea Sentinel and the Black Pearl. 

Dolphin success 

In fact, China has been deploying its own underwater drones throughout Indo-Pacific waters for some time now, ostensibly to gather environmental data, but increasingly with a capability of eventually taking on a direct role in future naval combat operations. 

According to observers, the country’s most advanced new underwater acoustic glider — the Dolphin — recently underwent extensive sea trials in the South China Sea.  

Based on earlier scientific underwater gliders, the Dolphin is reported to be able to dive to tremendous ocean depths with up to five months’ autonomous duration. 

During the sea trials, it successfully identified and tracked the movements of a 50m (164ft) research ship traveling at eight knots, at a range of 3.5nm; a 60m (196ft) merchant ship at 11 knots, at a range of 6nm; and a 99m (325ft) salvage ship at 14 knots, at a range of 7.5nm. 

The SeaGuardian drone can execute long-range, over-the-horizon, guided-missile targeting (Credit: General Atomics Aeronautical)

Kursk catastrophe 

Submarine tracking technology has evolved dramatically over the past couple of decades. 

Back in August 2000, the Russian navy found itself unable to locate one of its own nuclear-powered submarines, the Kursk, even after it had exploded and sunk 108 m (354 ft) to the bottom of the Barents Sea, killing all 118 crew on board, during a naval exercise.  

Ironically, a Norwegian spy ship that was shadowing the exercise managed to record the explosion and pinpoint the position of the distressed vessel immediately from a distance of 15nm. The information was offered to the Russians, but they refused to accept it. 

Last year, Norway’s Institute of Marine Research reported that the cables on seabed sensors used to track submarine activity off the country’s northern coast had been severed and removed — raising suspicions about deliberate sabotage by the Russian navy.  

Antarctic discovery 

Modern robotic submarine tracking technology is, though, thankfully, also being used in a much more scientific way than simply trying to track and destroy deep sea assets.  

The marine robotics company, Ocean Infinity — which deploys autonomous robots in fleet formations to obtain information from the seabed and ocean environments — played a major role earlier this year in the discovery of Ernest Shackleton’s ship, Endurance, which was crushed by sea ice before sinking 3,000m (9,800ft) to the bottom of the Antarctic’s Weddell Sea, more than 107 years ago. 

See the skills required to design and race a human-propelled submarine at the IMarEST's eISR submarine race and catch-up on recent naval engineering webinars and events on IMarEST TV (for IMarEST members only). 

Dennis O’Neill is a freelance journalist specialising in maritime