Tuesday, June 20, 2017

The Allure of Supercavitating Torpedoes

Appears 230mph super-torpedo tech is making comeback.


Dr. Gareth Evans, Naval Technology
20 June 2017

Alongside directed energy weapons and electromagnetic rail guns, supercavitating torpedoes repeatedly feature at the top of the wish list of must-have capabilities for any self-respecting navy of the future – and it is easy to see why. The allure of a rocket propelled super-weapon capable of delivering a nuclear or conventional warhead at speeds in excess of 200 knots is pretty self-evident, unless, of course, you are the one on the receiving end.
First developed into a workable design for the Soviet navy during the Cold War, the concept of supercavitating torpedoes has fascinated military engineers ever since, although little practical headway seems to have been achieved subsequently, aside from a number of stalled projects and aborted attempts over the years.
Now that may be about to change with the news that Russian scientists are once again looking at supercavitation and Iran is apparently getting in on the act, too. Back in October 2016, accounts began to appear of a program to develop a new weapon named Khishchnik (‘Raptor’), while on 7 May this year, Iranian forces reportedly test fired a Hoot high-speed torpedo – thought to be a reverse-engineered version of the original Soviet design – in the Strait of Hormuz.
It seems 230mph super-torpedo technology could be set for something of a revival.

What a drag

The speed of any torpedo is constrained by two fundamental factors – its method of propulsion and the laws of physics. Conventional versions are driven by propellers or pumpjets and although the fastest of these are undeniably swift, and considerably quicker than most ships, in the world of weapons where even the humble bullet flies supersonic, they are definitely more tortoise than hare.
One obvious way around that is to change the method of propulsion; swap electric motors and propellers for a rocket engine, and at a stroke you turn your torpedo into an underwater missile. The only problem is, doing that runs you headlong straight into the laws of physics, and that is a drag – quite literally.
Drag is the counter force that acts against any object moving through the water, and the greater the velocity, the greater the drag, which means that the constraints of fluid dynamics impose an effective speed limit of around 50 knots. Now, while as the Starship Enterprise’s fictional chief engineer Montgomery Scott was wont to say, “you cannae change the laws of physics”, you can sometimes get around them, and in this case, that involves wrapping your torpedo in a giant bubble of gas.

Supercavitation

The fundamental idea behind supercavitation is surprisingly simple. When water is forced around an object, such as a ship’s propeller, at high speeds the pressure drops around the trailing edge, and if it drops below the water’s vapor pressure, bubbles are formed in a process known as cavitation. Traditionally, it has been a problem for engineers because when the bubbles strike the propeller itself they then implode, damaging the material and leading to serious cavitation erosion over time.
However, in the late 1940s Soviet scientists began to wonder if by deliberately manipulating this effect to create a huge, sustainable mega-bubble, and then encasing a torpedo body within it as it hurtles through the water, hydrodynamic drag could be largely overcome. Two decades and six prototypes later, their work was to see practical supercavitation realized, and the emergence of a new weapon class, capable of remarkable submerged speeds.

Soviet Squall

For the Shkval (‘Squall’), which entered service in 1977, this was achieved by a specially designed flat nose cone, which deflects water outwards and initiates the supercavitaiton bubble. The envelope is then further extended and sustained by gases from the torpedo’s engine. Fired from standard 533mm torpedo tubes at a conventional 50 knots, the Shkval’s solid fuel rocket booster subsequently ignites and accelerates it to supercavitating speed, before a hydrojet sustainer kicks in to propel it on the final part of its way to the target.
Despite the obvious appeal of the technology, supercavitating torpedoes do have some major limitations. The need to keep as much of the torpedo body as possible out of contact with the water means that steering surfaces cannot protrude far out of the cavity, so course corrections are difficult, and any major change of heading would force part of the body out of the bubble, instantly increasing drag, and risking collapsing it altogether. Although with a maximum range of just 15km, the short transit time to target mitigated this potential problem in the Shkval, it could be more challenging for any torpedo intended to be fired from further away.
Additionally, rocket and hydrojet propulsion at velocities in excess of 200kts involves a huge amount of vibration and a great deal of noise. While a submarine firing a torpedo capable of that kind of speed probably has little to fear from a counterattack from its target, it will have betrayed its position very loudly to any other enemy vessels in the area and moreover, all that background racket renders the weapon itself as deaf as the proverbial post.
Using any type of sonar guidance at supercavitating speed is clearly a complete non-starter.

Enduring appeal

Nevertheless, the appeal of this submarine super-weapon is proving to be an enduring one for countries on both sides of the old Cold War divide.
In 2004, Diehl-BGT Defense announced the start of a supercavitating technology demonstrator program in cooperation with the German Navy. Barracuda was intended to have both submarine and surface launch capabilities, and be able to travel along both straight and curved attack paths, although ultimately the program ended without producing a deployable weapon.
Two years later, the US Defense Advanced Research Projects Agency (DARPA) commissioned General Dynamics to look into the technology. It seems that they were exploring the possibility of overcoming the sonar limitations by changing the design of the cavitation disc, altering the location of the transmitters and developing special noise-cancelling filters to cut out interference from the engine. Just how far they got along that particular track remains unknown, except to say that the project folded after a year, and US research into the technology effectively came to a halt five years later, in 2012.

Rise of the Raptor

Little is officially known about the new Russian Khishchnik, but there has been speculation that it will set out to overcome two of the principal shortfalls in the previous Shkval design – range and guidance.
Developing the Shkval’s hydrojet – essentially an underwater ram-jet burning a hydro-reactive metal fuel – back in the 1960s was arguably then as difficult a technical challenge as managing the supercavitation itself. While it enabled the weapon to outrun even the fastest conventional torpedoes four or five times over, it left it with less than a third of the range enjoyed by the best American versions. Hailed as the ‘killer of aircraft-carriers’, in reality Shkval required a launching submarine to penetrate so far into the carrier group’s anti-submarine coverage area that its own survival would have been put in question.
Roll on fifty years, however, and improved motors and better fuels could give the next generation of supercavitating torpedoes perhaps ten times that range, and possibly ten times the speed. Add to that a guidance system along the lines of what the DARPA/General Dynamics program envisioned and the Khishchnik would be a very potent beast indeed.
It remains to be seen whether this latest Russian project ultimately succeeds, or falters like others before it, but if it does, there will be some very big ticks appearing on those wish lists, as the world’s navies set out to arm their warships of tomorrow.

Sunday, June 18, 2017

Boeing Testing Cutting-Edge Submarine Off Palos Verdes Coast

The unmanned, ocean-spanning craft can reach a depth of 11,000 feet.

Staff, ABC 7
8 June 2017

RANCHO PALOS VERDES, Calif. – There's been a strange sighting off the Palos Verdes coast. It looks a little like a futuristic version of the Loch Ness monster.
But upon closer examination, it turns out to be a 50-ton, 51-foot-long monstrous underwater robot. It's the Boeing "Echo Voyager."
The unmanned undersea vehicle is now going through several months of trials at sea before setting off on its own with no crew and no tether to a support ship.
Powered by a hybrid electric battery system, it periodically surfaces to snorkel depth to recharge its batteries by raising a mast.
The Echo Voyager can reach an impressive depth of 11,000 feet.
It will be used for months-long surveillance and reconnaissance missions for defense, commercial and scientific customers.


Boeing, HII to Team on Unmanned Undersea Vehicles

Staff, Seapower Magazine
8 June 2017 

ARLINGTON, Va. — Boeing and Huntington Ingalls Industries (HII) are teaming on the design and production of unmanned undersea vehicles (UUVs) in support of the U.S. Navy’s Extra Large UUV program, Boeing said in a June 8 release.
“This partnership provides the Navy a cost-effective, low-risk path to meet the emergent needs that prompted the Navy’s Advanced Undersea Prototyping program,” Darryl Davis, president of Boeing Phantom Works, said in the release. “We are combining Boeing’s preeminent UUV maritime engineering team with our nation’s leading shipbuilder and Navy technical services company to get operational vehicles to the Navy years ahead of the standard acquisition process.”
Boeing currently is testing its newest and largest UUV, Echo Voyager, off the Southern California coast. The vehicle is designed for multiple missions and could include a modular payload bay of up to 34 feet, offering enhanced endurance and increased payload capacity over traditional UUVs. Echo Voyager is fully autonomous, requiring no support vessel for launch or recovery, enabling operation at sea for months before returning to port.
“We look forward to a long relationship with Boeing as we embark together to field this unmanned force-multiplier for the Navy,” said Andy Green, executive
vice president of HII and president of the company’s Technical Solutions division. “I am confident this team will continue redefining the autonomy paradigm for UUVs.”
The partnership will leverage design and production facilities in Huntington Beach, Calif.; Newport News, Va.; and Panama City, Fla., and will offer access to all the expertise and capability of Boeing and Huntington Ingalls Industries.

USM Makes History with First Graduating Class of Unmanned Maritime Systems Course

Erica Davis, WDAM 7
8 June 2017

The University of Southern Mississippi made history on June 1 with 15 students completing a first-of-its-kind certification in Unmanned Maritime Systems (UMS).
“This is akin to what NASA first did with spaceflight,” Rear Admiral Timothy Gallaudet said. “This class should be mighty proud because the national impact of this certification and the skills taught throughout the course will be felt for decades.”
The UMS program spanned over an intensive five weeks with students studying nautical science, 3-D positioning, ocean policy, and autonomous systems.
“This program was designed to provide a rigorous, hands-on academic program to introduce the students to unmanned maritime systems and the decision processes needed to operate them, “ said Monty Graham, Director of USM’s School of Ocean Science and Technology (SOST). “Students developed skills in disciplines such as electronics, programming, policy and application.”
The 15 students were made up of civilian and military personnel from the Naval Oceanographic Office, Fleet Survey Team and Naval Oceanography Mine Warfare Center based at the John C. Stennis Space Center; Submarine Development Squadron 5 based in Bangor, Washington; Naval Oceanography Special Warfare Center based in San Diego; the National Oceanic and Atmospheric Administration in based in Norfolk, Virginia; and the Naval Undersea Warfare Center based in Newport, Rhode Island.
The class’s instructor, SOST’s Dr. Vernon Asper, was challenged with packing 10 semester hours of teaching into just five weeks of class time.
“Scheduling was crucial because of how intensive the nature of the class is,” Asper said. “Seeing how quickly the students began to grasp the concepts and truly grow their understanding of the unmanned systems was incredibly gratifying as their teacher.”
In the five weeks, students learned core fundamentals of using gliders, powered unmanned underwater vehicles, and autonomous surface vehicles. Not only were students responsible for learning how to chart and pilot these vessels, but they also learned how to build them.
“Building the glider really brought a lot of the topics together for the class,” Asper said. “Seeing how the vehicle you’re using is made from inside to out put everything into perspective for them.”
Graham applauded the graduates as they received their certificates from USM President Rodney D. Bennett and Rear Admiral Gallaudet.
“In a normal academic world, 18 hours takes about 15 weeks,” Graham said. “These graduates worked every day, all day, for five weeks. Each of you should be very proud of the hard work you’ve put in to earn these certificates.
The UMS class is the first tier in a 3-tier program. Students going through the entire tier structure will graduate with a full graduate degree.
“Look around the room at your fellow graduates,” Gallaudet said. “Each of you has embarked on a journey no one else has attempted. The work you have put in for the last few weeks has advanced the defense of the United States immensely and we can’t wait to see what you do next.”


Russia’s Navy to Operate 7 Next-Generation Ballistic Missile Subs by 2021

Franz-Stefan Gady, The Diplomat
12 June 2017 

The Russian Navy is expected to operate seven Project 955 Borei-class (“North Wind”) aka Dolgorukiy-class nuclear-powered ballistic missile submarines (SSBNs) by 2021, Russia’s Defense Minister, Sergei Shoigu, told the upper house of the Russian Parliament at the end of May.
“By 2021 the naval strategic nuclear forces are expected to have 13 submarines in their combat structure, including seven promising Borei-class submarines with new Bulava missile systems,” Shoigu said, according to TASS news agency.
The modernization of the Russian Navy’s aging fleet of SSBNs remains one of the top priorities for the government and despite fiscal constraints and various technical challenges (and unlike other weapons programs) there have not been major delays in the floating out of Borei-class boomers.
“The Borei-class is the new sea leg of Russia’s nuclear triad and is slowly replacing obsolete Soviet-era Project 941 Typhoon-class and Project 667 BDRM Delta IV-class submarines,” I noted in March.
The first advanced variant of the Borei-class, dubbed Project 955A Borei II-class, is expected to be floated out in June of this year. The Russian Navy plans to operate eight Borei-class SSBNs–three Borei-class and five advanced Borei II-class subs–by the 2020s. As I explained elsewhere (See: “Russia Will Start Constructing New Ballistic Missile Submarine in December”):
In comparison to the Borei-class, Borei II-class submarines are fitted with four additional missile tubes, boast smaller hulls and cons, and feature improved acoustics and lower sound levels, next to a number of other technical improvements.
Both variants of Borei-class subs will be armed with Bulava (RSM-56) intercontinental ballistic missiles (ICBMs). The Borei-class will be capable of carrying up to 16 Bulava ICBMs, whereas the improved Borei II-class can carry up to 20 ballistic missiles.
The improved variant of the Borei-class will be capable of launching 96-200 hypersonic, independently maneuverable warheads, yielding 100-150 kilotons apiece. 
The exact status of the Bulava ICBM remains unclear as a number of tests of the missile system have ended in failure. “Since 2004, the missile has been tested 25 times, with varying degrees of success. The last five tests, conducted between September 2014 and September 2016, were reportedly all successful,” I explained in September of last year. However, Russia’s MoD acknowledged that of the two missiles fired during last year’s test, only one hit its designated target with the second missile self-destructing in midflight.
Three Borei-class submarines have been commissioned so far. One boomer, the Yuri Dolgoruky, currently serves with the Russian Navy’s Northern Fleet, while the remaining two–Alexander Nevsky and Vladimir Monomakh—have joined the Pacific Fleet. The first improved Borei II-class SSBN, christened Knyaz Vladimir, is expected to be commissioned in 2018, following a two-year delay due to contract disputes.

Is India's Submarine Fleet Defenseless?

Franz-Stefan Gady, The Diplomat
12 June 2017

With the recent cancellation of a $200 million contract for 98 Black Shark heavyweight torpedoes at the end of May, the Indian Navy’s new submarine fleet continues to lack adequate defense capabilities against enemy subs and surface warships in the event of a conflict.
India’s Ministry of Defense (MoD) has canceled the order for Black Shark heavyweight torpedoes, built by torpedo maker Whitehead Alenia Systemi Subacquei (WASS), a subsidiary of Italian arms manufacturer Finmeccanica, due to corruption allegations involving another Finmeccanica subsidiary, Agusta Westland. According to the Indian MoD, Agusta Westland representatives allegedly paid bribes for a 2010 purchase of 12 AW medium lift helicopters, which resulted in the termination of the contract in 2014 and the purported blacklisting of the company.
The recent cancellation of the torpedo order was a direct result of the corruption allegations involving the European defense contractor and the Indian National Congress political party. The Black Shark torpedo was specifically purchased for the Indian Navy’s future fleet of six Scorpene-class (Kalvari-class) diesel-electric attack submarines. A second batch of 49 Black Shark torpedoes was also to be installed aboard India’s domestically developed and built Arihant-class of nuclear-powered ballistic missile submarines.
According to Indian media reports, at least three of India’s future fleet of four to five Arihant-class SSBNs were expected to carry the new torpedoes. The cancellation of the order could mean a two- to three-year delay in the launching of the second sub of the class, the Aridaman, due to torpedo tube modifications. Alternatives to the Black Shark torpedo are the German-made SeaHake heavyweight torpedo and France’s F21 Artemis. Given the lack of transparency regarding the Indian’s MoD blacklisting policy vis-à-vis, the Black Shark torpedo could also participate in a new bid. Furthermore, the Indian Navy inducted the domestically-produced Varunastra 533 millimeter heavyweight torpedo last summer. The Indian-made weapon is currently adopted to fit the torpedo tubes of Indian submarines. (The Indian Navy has ordered 73 Varunastra torpedoes.)
Senior naval officials say that it will take time to select a new heavyweight torpedo and an interim solution will be sought. “There will be some alternate torpedoes as an interim solution. The heavy weight torpedoes will take some time. Those which are already in use in other platforms will be used in these (Kalvari-class) submarines,” a senior Indian naval official told The Economic Times in early June. However, the Indian Navy’s existing stock of Russian-made torpedoes (as well as the Varunastra) cannot be fired from subs of the Arihant-class or Kalvari-class without substantial hardware and software modifications.
As I reported last week, the second Scorpene-class (Kalvari-class) diesel-electric attack submarine, christened Khanderi, has recently begun sea trials off the coast of Mumbai. The lead submarine of the class, Kalvari, is expected to be commissioned in July or August following the successful completion of sea trials and weapons tests, which includes the test firing of a German SeaHake torpedo and French-made Exocet SM39 anti-ship missiles. As I explained elsewhere:
The acquisition of the Exocet came under intense scrutiny following the August 2016 disclosure of a data leak at French shipbuilder Direction des Constructions Navales Services (DCNS), which publicly revealed sensitive details on the anti-ship missile including launch details, the number of targets the missile is capable of processing, and how many targets could be downloaded before firing.
Nevertheless, the Indian MoD insisted that the leaked data does not constitute a security compromise and reiterated its intention to procure the missiles for the Kalvari-class.
The INS Arihant was secretly commissioned in August 2016. The lead ship of the Indian Navy’s new class of SSBNs primarily serves as a technology demonstrator. “In comparison to the lead ship of the class, subsequent boats will be larger (e.g., they will boast eight rather than four launch tubes), operate a more powerful reactor, and feature a host of other technical improvements,” I explained in October 2016. Arihant-class subs are expected to be armed with K-4 and K-15 Sagarika nuclear-capable submarine-launched ballistic missiles (SLBM).

Can The U.S. Afford Modern Nukes?

Matthew R. Costlow, Wall Street Journal
14 June 2017

When President Obama left the White House, he punted on a tough choice: how to modernize the U.S. nuclear force. In the coming weeks, the Congressional Budget Office is expected to release a report that estimates modernization as currently proposed would cost $1.2 trillion over 30 years, or about $40 billion a year. Congress and the Trump administration shouldn’t be intimidated by the ostensibly big number.
The plan analyzed by the CBO would replace the nuclear delivery systems of bombers, missiles and submarines with new ones that incorporate the latest safety and survival features. These changes would enable some systems to perform well into the 2080s. It’s ambitious, but this program isn’t the budget buster nuclear disarmament supporters describe.
Under the plan, spending on the nuclear arsenal would peak in the late 2020s at about 6.5% of the Defense Department budget, up from 3.2% today. Recall that military spending consumes only about 15% of the federal budget.
But determining whether modernization is affordable involves more than cost considerations. The Pentagon simultaneously has to consider its priorities and the costs of weapons systems when determining the best way to protect U.S. interests. According to the Defense Department, the two highest priorities of U.S. strategy are “the survival of the nation” and “the prevention of a catastrophic attack against U.S. territory.” The Pentagon’s Quadrennial Defense Review lists “a secure and effective nuclear deterrent” at the top of a list describing how to achieve such priorities.
Given that the U.S. nuclear arsenal helps to deter the only existential threat to the U.S., major nuclear war, its value can’t be measured by traditional dollar metrics alone. Budgets are about trade-offs and priorities. As the vice chairman of the Joint Chiefs of Staff, Gen. Paul Selva, testified earlier this year, “We are emphasizing the nuclear mission over other modernization programs when faced with that choice.”
Critics will cry that every dollar spent on nuclear weapons, which have not been set off in anger since World War II, is a dollar taken from those who are fighting wars right now. But as then-Defense Secretary Ash Carter explained in a speech last year, U.S. nuclear forces are the “bedrock” of American security and the “highest priority mission” of the Defense Department. They enable current war fighters to achieve their missions.
Even those in the military who could stand to miss out on spending increases because of nuclear modernization efforts, like U.S. Army Chief of Staff Gen. Mark A. Milley, support modernization: “It’s not even an Army system and it needs to be overhauled and brought back up to the level of readiness.”
The federal government can afford to spend less than 1% of its multitrillion-dollar budget on nuclear modernization. And with Russia, China and North Korea all upgrading their nuclear weapons capabilities, just about the only thing the U.S. can’t afford is to end its modernization efforts before they begin.