^ William Beebe (left) & Otis Barton near the Bathysphere
Image Courtesy of the National Oceanic and Atmospheric Administration (NOAA) at http://oceanexplorer.noaa.gov/explorations/05stepstones/logs/aug15/aug15.html
Retrieved From https://en.wikipedia.org/wiki/File:WCS_Beebe_Barton_600.jpg
Submarine Drones: A Rising Star
Just over a year ago, in April 2015 to be precise, the U.S. Navy created a position titled First Deputy Assistant Secretary of the Navy for Unmanned Systems. By October 2015, they appointed Brigadier General Frank Kelley to the post.
Lest you wonder what the fuss is all about, the appointment is representative of a paradigm shift in the approach of the U.S. Navy. Or the approach of any other top class naval force and shipping company in the world. Shipping is migrating towards greater use of submarine drones.
Submarine drone provide decision makers with a viable alternative to deploying humans for perilous and cumbersome missions such as detecting and neutralizing sea mines, patrolling disputed territories, and surveying war and conflict ravaged areas. Precisely why they elicit so much interest.
Consider this. The U.S. Department of Defense may well spend $232.9 million in fiscal year (FY) 2016 for procuring unmanned underwater vehicles (UUVs). This is $86.7 million more than the amount spent in FY 2015. And, this does not include the research funding.
Not that the world is too far behind. Apparently, the Russians are building a long range submarine drone with nuclear capacity. If we ever needed evidence of the gravity with which the world is looking at drones, it is this.
That apart, the Chinese government is financing fifteen separate university research programs on surface and underwater drones with a focus on UUVs. Back in 2014 itself, Japan and the U.S. joined hands to make a 33-foot UUV that uses SONAR to patrol along pre-programmed routes.
Estimates by Business Insider place global spending on drone procurement at a stunning $98 billion for the 2014-24 period. And, drones are not merely about navies. Of the $98 billion, $11.78 billion will go into purchasing commercial drones. The spending on research is in addition to this amount.
Evolution of Underwater Exploration & Underwater Drones
Much like the space is to us today, the ocean was for the ancient people – an infinite stretch of wilderness hiding in its gut tons and tons of unknown elements. It is so even today, for a great part of it remains unexplored. Definitely, an area of intense curiosity!
There was a time when the span of underwater exploration was limited to the duration a diver could hold his breath under water. The creative genius of Leonardo da Vinci is known to have sketched a diving suit with a breathing tube resting on a cork float.
Although Karl Klingert invented the Helmet Suit as far back as 1797, the real breakthroughs came in the early 20th century. Between 1930 and 1934, William Beebe and Otis Barton used the unpowered Bathysphere to explore the depths around the Bermuda coast.
Then in 1943, Frenchmen Jacques Cousteau and Emile Gagnan devised the Aqua-Lung that enabled divers to breathe underwater by supplying air as needed. Continuous flow of air in earlier underwater breathing devices exhausted oxygen supply and limited the underwater duration of divers.
First launched in 1964, the U.S. Navy owned and operated submersible Alvin has collected data that was
subsequently used in 2,000 scientific papers. It explored the Cayman Tough, the deepest point of the Caribbean Sea in 1964.
Now, the director of blockbusters such as Titanic and Avatar, James Cameroon, has another side. He is a diving enthusiast with 72 submersible dives to his credit. In 2012, as an explorer with the National Geographic he dived solo in the Mariana Trench using a submersible.
Technology is valuable. Agreed. But life is precious. While these submersible devices are technically accomplished, they still require a human inside them. There is a limit to human endurance in the cold, dark, high-pressure, and creepy environs that the underwater world presents.
Please note, static water pressure increases with depth at the rate of around 0.1 bar per meter of seawater if we take the average density of seawater as 1027 kg / m3. The density of pure water is 1000 kg / m3. Seawater is denser because of dissolved salts.
Enter, submarine or underwater drones. These can be:
- Remotely Operated Underwater Vehicles (ROVs): are tethered to the surface support ships and operated by the pilot team
- Unmanned Undersea Vehicles (UUVs): are free of wired connections and operate autonomously
SPRUV or the Special Purpose Underwater Research Vessel was among the first UUVs. The Applied Physics Laboratory at the University of Washington developed it in 1957. It had an endurance of 4 hours and could dive up to 10,000 feet.
When the SPRUV program ended in 1979, there were many UUVs around. Of particular note was the Argo that discovered the wreckage of the famous Titanic in 1985. Four years later, it uncovered the German warship Bismarck that the Allied forces sunk so resolutely during World War II.
For the U.S. navy, UUVs are important for mine detection. Traditional minesweeping using special ships called minesweepers has its own sets of limitations as the mine-caused damage to two U.S. warships during Operation Desert Storm amply demonstrated in the early 1990s.
Responding quickly, Northrop Grumman developed the Near-Term Mine Reconnaissance System (NMRS) in 1996. This was a two-vehicle device launched from a submarine’s torpedo tube and connected to a vessel using a fiber optic tether.
Soon the Long-Term Mine Reconnaissance System (LMRS) replaced the NMRS. The product of LMRS was Boeing’s 20-foot AN/BLQ-11 drone, the details of which we shall see later in this article.
In 2003, submarine drones got their first opportunity to operate in a war zone when Remote Environmental Monitoring UnitS (REMUS) UUVs cleared sea mines in the waterways around the port of Umm Qasr in Iraq.
REMUS submarine drones are among the most widely used UUVs. The Woods Hole Oceanographic Institution and the Massachusetts-based drone maker Hydroid initiated the REMUS program.
MK18 Mod2 Kingfish, a variant of REMUS 6000 – the highly useful, torpedo-shaped drone that can carry a great payload of diverse sensors to extreme depths – costs $1.3 million per piece.
It will soon replace sea lions and dolphins for detecting underwater mines. The U.S. Navy employs these creatures for mine detection under its Marine Mammal Program.
Unmasking sea mines with drones is a U.S. Navy priority under its Unmanned Undersea Vehicle Master Plan 2004. This is far safer than sending out humans and minesweeping vessels for such a life and limb threatening job.
With the Sea Dragon helicopters and Avenger class minesweepers inching towards retirement, the U.S. Navy has stepped up its efforts to replace them. They are therefore looking to integrate submarine drones with existing manned vessels such as the Littoral Combat Ships (LCS).
Some of the other popularly used, anti-mine submarine drones / drone systems include:
- Remote Multi-Mission Vehicle (RMMV) by Lockheed Martin
- Knifefish UUV by General Dynamics
- Bluefin-21 by Bluefin Robotics
- Battleship Preparation Autonomous Vehicle
- Surface Mine Countermeasures
Of particular interest here is Lockheed Martin’s Remote Minehunting System (RMS). The U.S. Navy has allocated as much as $87.6 million for the primary product of the above system, the Remote Multi-Mission Vehicle (RMMV).
But with the cost of a single unit of RMMV more than doubling from $13 million in 2007 to $27.7 million in 2015, the RMS has come under fire from certain Senators who have even called for scrapping the program altogether.
Likewise, the Knifefish UUV comes at an exorbitant $17.4 million apiece. And, there is the Large Displacement UUV (LDUUV) available for $38.8 million. Apart from detecting mines, the LDUUVs also deliver payloads, and gather intelligence. These too, are in the eye of a political storm.
Acquisition apart, research and development of submarine drones is another area of interest for the U.S. Navy. Some of the interesting developments include:
- Silent NEMO looks to create biometric UUVs that can swim like a fish. The Department of Defense has earmarked $4 million for Silent NEMO
- Hydra will create a network of assets that can respond rapidly to evolving hazards. The Defense Advanced Research Project Agency (DARPA) has reserved $32.7 million for the same
- Upward Falling Payloads (UFP) is a $22 million DARPA program that aims to build cost effective UUVs that can be deployed at numerous locations
When activated remotely, they will surface and deliver a waterborne or airborne payload of explosives or supplies
- Distributed Agile Submarine Hunting (DASH) is a $8.5 million DARPA mission that seeks develop UUVs that can effectively track submarines
Popular Naval Submarine Drones
Lockheed Martin’s Remote Minehunting System (RMS) is the most mature autonomous, semi-submersible vessel of its kind with the Navy. It is the primary component of the mine reconnaissance ability of the Navy’s Littoral Combat Ship (LCS) Mine Countermeasures (MCM) Mission Package.
Consisting of a Remote Multi-Mission Vehicle (RMMV) and an AN/AQS-20A variable depth sensor, the RMS bridges a treacherous pitfall in mine detection by eliminating the need for exposing sailors and expensive ships to the hazards of underwater mines.
RMS does this by enabling unmanned detection, classification, localization, and identification of bottom and moored mines in littoral regions. Its main merits include:
- Superior Detection Rate: that is more than twice that of the average historic rates
- Endurance: 24-hour endurance for continuous surveillance
- Versatile Control: remotely controlled from diverse maritime platforms and shore-based facilities
- Remarkable Communication System: loaded with real-time, encrypted line-of-sight and over-the-horizon communications mechanisms to control the vehicle
- Robust: can operate in heavy seas and at great distances over the horizon
General Dynamics’ Knifefish is a heavyweight MCM UUV and is an adopted version of the Bluefin-21 – the civilian UUV that made waves in 2014 for its pivotal role in hunting the ocean floor for the wreckage of the luckless Malaysia Airlines Flight 370.
Contoured like a torpedo and driven by a propeller, the Knifefish UUV is expected to start sweeping out mines by working with Littoral Combat Ships (LCS) from 2017.
Its synthetic aperture sonar detects and locates buried and floating mines. After receiving data from Knifefish, the LCS destroys the mines. Lithium ion batteries lend it an endurance of 16 hours on pre-programmed search missions.
Each LCS can operate two Knifefish UUVs that may be armed with real-time data transmission capacity before final deployment. Its modular design allows for quick and flexible reconfiguration to deal with rapidly changing mission requirements. Chief merits include:
- ability to detect, classify, and identify proud, volume, and buried mines even in highly cluttered environs
- plug and play integration with ship systems and mission modules
- fast mission turnaround times
- compatible with numerous ship types
- intelligence support to other mine neutralization mechanisms
Bluefin-21 is a highly modular AUV that can accommodate diverse payloads for a whole range of missions including detection and location of mines and unexploded ordnances.
It can dive up to 1,500 m. At 3 knots and carrying standard payload, its endurance hits 30 hours. The Bluefin-21’s top speed is 4.5 knots. Sterling features include:
- accurate navigation with the Inertial Navigation system (INS)
- simple operations through intuitive software
- scalable, modular, and versatile
- can be conveniently transported via aircrafts
First deployed in 2012 by the U.S. Navy, the MK18 Mod2 Kingfish is a variant of the proven REMUS 6000 technology. Its Small Synthetic Aperture Sonar Module (SSAM) configuration offers better detection of buried targets, higher image resolution, and wider swath.
REMUS 6000 drones can explore depths of up to 6,000 m while 4,000 m depth variants are also available. They are
easy to operate, carry a wide spectrum of sensors, and can execute littoral as well as deep sea operations.
In December 2014, the U.S. Navy completed testing of GhostSwimmer, a 5-foot drone that swims like a large fish – by oscillating its tail fin. This improves its stealth. The Rapid Innovation Cell of the chief of naval operations developed the GhostSwimmer under its project, Silent NEMO.
This is another example of the rapidly rising use of biomimicry, the imitation of the techniques used by birds and animals in designing machines. At 100 pounds, the GhostSwimmer bears striking resemblance with a tuna.
Quieter than similarly-sized, propeller-driven drones, the GhostSwimmer can undertake reconnaissance, intelligence collection, and friendly hull inspections up to 300 feet. It can operate with or without a tether.
Created in 1958, the Defense Advanced Research Project Agency (DARPA) is an agency under the U.S. Department of Defense that looks into developing emerging technology for military applications.
Developed by DARPA, Hydra aims to act as a force multiplier by making capabilities independent of the platforms that have traditionally delivered them. This will put in place a distributed network of unmanned platforms and payloads that can be launched remotely as and when needed.
Each payload module will include numerous payloads and will be stored underwater inside a standard enclosure. When activated, the module will launch the specific payload. This will minimize response times and operational costs.
Navies will deliver the Hydra system via submarines, ships, and aircrafts. Hydra overcomes an inherent limitation
of any asset – it can be present at only one location at a time.
Upward Falling Payload (UFP) is also a DARPA’s initiative and is quite similar to Hydra. UFP will deploy unmanned, non-lethal systems far and wide over the ocean floor. These can lie dormant for years before activation makes them come to the surface i.e. they will fall upward.
These systems will be more cost effective and provide better results than long-range, unmanned naval systems. And with nearly half of our oceans over 4 km deep, there are great many places to hide these.
Distributed Agile Submarine Hunting (DASH) is another of DARPA’s projects. It seeks to place submarine detection nodes at various locations on the ocean floor. With large fields of view, these nodes can detect submarines moving over them.
Submarines are an immense threat to ships and maritime infrastructure simply because they operate from under the water and are hard to detect. Plus, their acoustic signature has come down to unbelievably silent levels. The DASH program aims to counter this silent, deep sea killer.
Boeing AN/BLQ-11 is a 20-foot UUV capable of running ahead of the Seawolf, Los Angeles, and Virginia class submarines for detecting mines. Equipped with a forward looking and a side-scan synthetic aperture sonar, it has an endurance of 120 miles.
It was part of the U.S. Navy’s Mission Reconfigurable UUV System (MRUUVS) program that ended in December 2008 on account of the AN/BLQ-11’s engineering and technical limitations.
Like all other technologies, drone technology will take its own time to mature. As the heated debate over Lockheed Martin’s Remote Minehunting System (RMS) has demonstrated beyond any reasonable doubt, creating viable alternatives is an exceptionally tough and snail-paced task.
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