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Anti submarine warfare
Anti submarine warfare is slowly taking the center stage of naval warfare as the world is getting dependent on sea for trade and commerce which makes it important to keep vital sea lanes of communications open even during the height of any tension or conflict.

But the ASW is a game changer for any navy and this initiates rounds of ‘cat and mouse’ game as who wins and who loses while securing the SLOC open and minimize the damage to naval assets.    

The US Navy emerged from World War II victorious in two undersea warfare campaigns. In the Battle of the Atlantic, US and allied antisubmarine forces beat back the challenge posed to their sea lines of communication by Doenitz's U-boats, while in the Pacific, a pro-submarine campaign was waged by American submarines that cut the sea lines of communication within Japan's Greater East Asia Co-Prosperity Sphere.

In the years immediately after the war, the US Navy confronted a major challenge to its undersea warfare dominance.

German submarine development, driven by the rigors of waging the Battle of the Atlantic against the Allies' increasingly potent ASW forces, had leapt forward during the course of WWII.

By the end of the war, using snorkels, greater battery capacity, and better hull forms, the Kriegsmarine had deployed Type XXI submarines with vastly improved offensive performance while submerged.

These came too late to influence the outcome of the war, but they were a harbinger of things to come, since their designs also fell into the hands of the Soviet Union.

Soviet submarines based on these German designs threatened to render obsolete much of the US Navy's ASW posture, which had been focused on dealing with submarines that lost a substantial portion of their offensive capabilities when forced to submerge.

At the same time, the Soviet Union, being a continental power, threatened to make the US Navy's victorious submarine force irrelevant, since submarines were primarily useful as an anti-surface weapon against merchant shipping, and the Soviet Union could easily survive without merchant shipping.

Early innovations

Out of this challenge grew two initially separate innovations which, when brought together, formed one of the cornerstones of the US Navy's Cold War ASW posture.

The first innovation involved the exploitation of passive acoustics to detect and track submerged submarines, using the sounds they generated as a signature.

Passive sonars significantly increased the range at which submerged submarines could be detected compared to active sonar, allowing for very wide area searches by ocean-wide sound surveillance systems, which in turn could be used to accurately cue ASW platforms to localize and prosecute the submarine contact.

The second innovation began with the embrace by the US Navy's submarine community of ASW as its primary Cold War mission.

Although this focus on ASW predated the introduction of nuclear power, its full potential was realized in the early 1960s when quiet nuclear submarines were developed that could hear their louder Soviet counterparts at much greater ranges than they themselves could be heard.

This acoustic superiority lasted almost through to the end of the Cold War. Submarines were certainly never the only ASW instrument during the Cold War. Maritime patrol aircraft also played a key role as undersea surveillance systems became fully operational in the early 1960s.

Patrol aircraft offered speed that submarines lacked, making them particularly useful in the initial localization of a contact which could then be handed off to a platform with more endurance, like a nuclear submarine.

The surface warfare community was slowest to change its traditional ASW methods, remaining dependent on active sonar and short range ASW weapons until the late 1970s.

Then, in response to the deployment of more capable Soviet submarine-launched antiship missiles, surface combatants also embraced passive acoustics and long range, shipborne ASW helicopters.

By the early 1980s, all of the Navy's platform communities were being used successfully in ASW operations against Soviet submarines, and increasingly these operations demanded a high degree of coordination as Soviet submarines became quieter.

Earlier in the Cold War, when U.S. acoustic superiority was still unchallenged, each platform community's ASW operations had been relatively independent of each other.

This independence reflected a fairly natural division of labor based on the strengths and weaknesses of each ASW platform.

Thus, submarines went forward into contested waters where other ASW platforms could not operate, maritime patrol aircraft used their speed to prosecute long range contacts generated by underwater surveillance systems, and surface combatants utilized their endurance to provide a local screen for battle groups and convoys.

The key to success in these relatively uncoordinated operations was maintaining a high degree of acoustic superiority over Soviet submarines. Ironically, that superiority began rapidly waning in the 1980s, just as the Cold War was ending, in an echo of the end of World War II.

This saved by the bell ending to what was the third battle of the Atlantic was fortunate, but current trends in America's external security environment may confront the US Navy with new ASW challenges not unlike those it avoided when the Soviet Union collapsed, albeit on a smaller scale.

Security concerns

First, the threat to American acoustic superiority resulting from the first Soviet deployments of the Akula in the mid 1980s may recur in today's security environment with the increasingly wide proliferation of modern non-nuclear submarines.

Deployed relatively close to their homes, in or near littoral waters through which the United States may need to project power from the sea, these submarines pose a potentially formidable threat.

With a competent crew and the kind of advanced weapons that are now widely available in global arms markets, a modern nonnuclear submarine deployed in its own backyard might become a poor man's Akula.

Of even more concern is the fact that modern weapons, like wake homing torpedoes for example, tend to reduce the demands on submarine crews, making even less competent crews too dangerous to ignore.

Second, important elements of the American response in the mid 1980s to very quiet Soviet nuclear submarines are likely to be relevant to dealing with modern non-nuclear submarines.

The key element of this response was to coordinate the efforts of the historically independent ASW platform communities.

In coordinated ASW, a very quiet opposing submarine might first be detected as a transient contact at long range by off board ocean surveillance systems like SOSUS or SURTASS.

This information might then be used to cue maritime patrol aircraft to rapidly search the possible contact area and localize the submarine within it.

The prosecution of the contact might continue with platforms of higher endurance like submarines or surface ships, with the latter using its unique command and control capabilities to orchestrate a combined air, surface, and sub-surface effort culminating with the threat submarine being localized by several ASW helicopters, a tactical situation that even the best nuclear submarines cannot normally escape.

At the same time, in the background, the off board sensors comprising the ocean surveillance system would be constraining the threat submarine's offensive capability by forcing him to keep his speed down and limiting his ability to communicate.

These sensors could also be reverse cued by the prosecuting forces in case the latter lost contact with the target, creating higher probabilities that the target could be reacquired and the prosecution continued.

If such a coordinated approach to ASW has continuing relevance today, it needs to be a focus of both current training and future research and development.

Concerns about the trends in these areas have recently provoked enough debate over ASW within the Navy and DOD to warrant a fresh look at this mission area.

Nowadays, Chinese and Russian submarine forces are flexing their prowess in the undersea domain by operating further from their respective country’s homeport-in some cases within striking distance of the United States.

Given the expansion in operations, anti-submarine warfare (ASW) platforms on both coasts of the United States will be required to monitor and defend the nation more frequently.

Foreign submarine operations near the homeland are not necessarily immediate threats, but do require careful thought as the Navy prepares to execute future ASW missions.

As budget and US naval policymakers continue to plan for the future, ASW must remain a high priority for either homeland or overseas defense. The US Navy has new platforms and technology coming online that can provide a significant advantage in the undersea domain.

China possesses a large and increasingly capable submarine force. China has expanded their undersea reach as evident in the deployment of a Chinese nuclear submarine in the Indian Ocean.

The deployment demonstrates extended submarine operations and the capability for China to deploy nuclear submarines within ballistic missile launch range of the United States, within the exclusive economic zone (EEZ), or potentially closer to territorial waters.

As China continues sustained undersea operations, proficiency will likely improve with time as well.

The expansion of China’s nuclear submarine fleet will also allow operations further from the Asia Pacific region in the coming years.

China is in the process of building four new improved variants of the Shang class nuclear submarine and working on a robust diesel submarine fleet.

Given China’s submarine capability to transit and operate in the Indian Ocean and with continued submarine growth, a future nuclear submarine deployment off the West Coast of the United States may occur in the next five years or possibly sooner.

The purpose of future submarine deployments may serve as a deterrence, presence or collection mission against the United States-creating an increased requirement for naval assets to monitor and ensure security for the nation.

As China increases their submarine role in maritime operations, Russians are simultaneously increasing their Navy’s importance.

It is expected that in the next two years, Russia will begin construction of nine submarines.

Russia has already commissioned two Borei class nuclear submarines and plans to build six more. This new submarine is a notable threat carrying sixteen SS-NX-32 Bulava intercontinental ballistic missiles (ICBMs) and six SS-N-15 cruise missiles.

In addition, the Russian navy plans to add seven Severodvinsk class nuclear attack submarines by 2020 with intentions for reaching a total of sixteen.

With Russia’s construction of new submarines and leadership touting naval strength, more submarine operations near the United States are possible.

Since the end of the Cold War, Russia for the most part has been non-existent in operating nuclear submarines near the United States, but that may change.

Russia recently increased rhetoric against possible US submarine operations. Russia publicly stated an IL-38 ASW aircraft chased away a US nuclear submarine that was operating in the Barents Sea.

A future increase in submarine construction and operations by both countries are not the only development of concern in the undersea domain.

UUV deployment

Internationally, the development and use of unmanned underwater vehicles (UUVs) for military, education, and commercial use are expanding. In the military realm, developed countries are exploring UUV deployment from submarines that will create a new dynamic in the undersea domain.

As autonomous technology becomes more mature, UUVs will also operate independently in areas of potential crisis or strategic importance.

With a future increase in UUV operations, the ability to track UUVs in the undersea will be equally difficult and require improved sensor and processing capability.

To meet expanded foreign submarine operations and UUV technological advancements, the U.S. surface naval force employs state of the art ASW technology aboard numerous Arleigh Burke class destroyers.

The SQQ-89A(V)15 Combat System, which will be aboard 64 destroyers by 2020, and the new Multi-Functional Towed Array (MFTA) are game changers in ASW operations.

The combined capabilities alter how the surface navy searches and tracks submarines. With enhanced sensor capability and data processing, the surface naval forces have an increased role in integrated ASW operations.

ASW surface ships can remain longer on station in comparison to aircraft and also provide real time command and control capability beyond that of a submarine.

In stride with the surface US navy’s technological advancements, the aviation community has new platforms to meet the ASW mission.

The MH-60R Sea Hawk helicopter and the P-8A Poseidon aircraft are to be fully integrated in the fleet by 2020.

The new platforms are already providing an improved ASW capability in fleet operations. The MH-60R has been forward deployed in Japan and operating in the Asia Pacific region since 2012.

However, recently six P-8A aircraft completed an inaugural and successful deployment to the Asia Pacific.

The P-8A adds an improved sensor search capability by utilizing a multi-static active coherent (MAC) system, which is comprised of sonobuoys (source and receiver) and advanced processing.

In addition to the new platforms and technological advancements, all ASW ships and aircraft in the future will employ the Mk 54 lightweight torpedo, which integrates several years of weapons technology.

By 2020, these new improvements collectively in the surface and aviation communities will create a powerful ASW capability.

However, the US Navy is building a fleet (sensors and platforms) with enormous ASW capability that will create an integrated ASW machine.

ASW is a complicated warfare area, and proficiency can only develop through extensive textbook and practical training, at both the officer and enlisted levels.

However, submarines are like steel sharks – quiet, silent, and deadly. They are designed to hunt and kill.

Occasionally, it becomes necessary to find and destroy them-to keep open sea-lanes of communication, to sweep an area and make it safe for Allied shipping.

Destroying a submarine is the hardest task in naval warfare. Learning ASW takes time, training, and experience to fully understand how to plan and execute ASW operations.

Of all the topics associated with ASW, oceanography (undersea environment) is the most difficult to grasp and essential in dominating the undersea domain.

When comparing the undersea with other warfare area such as anti-air warfare, the science and understanding of the ASW operating environment is a more complex tactical problem.

Given the complexity of ASW, training personnel in mastering oceanography and anti-submarine operations must remain a high priority.

For the last twenty years or more, ASW has not been a significant operational requirement as a result of the Cold War ending and a decade of fighting in the war on terrorism.

A culture change from a primarily air warfare centric navy to an emphasis more in ASW must occur to improve proficiency among naval personnel at all ranks. This culture change must occur from the top down led by the Navy’s senior officers afloat and ashore.

Another consequence of multi-mission pull is operational, and will grow in significance to the extent that the Navy embraces new net-centric warfare schemes that seek to exploit the Revolution in Military Affairs at sea.

NCW capability

Net-centric warfare exploits the fact that platforms and sensors can be netted together with wideband communication links to form a system or net that is greater than the sum of its parts.

A good example is the US Navy's Cooperative Engagement Capability (CEC) which links together air and missile defense assets in ways that allow one platform to guide a missile launched by another at a target first detected by a third.

The CEC and other systems like it are easiest to imagine for operations by widely dispersed platforms on the surface and in the air, where detection ranges extend out to the horizon and supporting wideband communication links are relatively easy to arrange, neither of which is a characteristic of the undersea environment, where detection ranges against a very quiet target are short and wideband communications all but non-existent.

Thus, above the surface, the trend is for platforms to disperse, while ASW operations against quiet submarines still require a higher degree of concentration.

This does not mean that a net-centric approach to ASW will not eventually be developed, but it may mean that in the interim the operational commander at sea will increasingly face a dilemma about how he deploys his platforms, since the demand for the many missions they each perform is likely to arise concurrently rather than sequentially.

Since the beginning of the 20th Century, submarines have been the weapon of choice for weaker naval powers that wish to contest a dominant power's control of the seas, or its ability to project power ashore from the sea.

This is because submarines have been and are likely to remain the weapon system with the highest leverage in a battle for control of the ocean surface.

No other individual platform compares to a modern submarine, whether nuclear or non-nuclear, in its ability to combine a potent offensive punch with the ability to evade counterattack by opposing forces.

Today, the steady proliferation of modern, non-nuclear submarines, fueled by export or die imperatives in Western defence industries, and the cost-averse politics of fighting distant wars over less than vital interests conspire to make it both important and difficult for the US Navy to maintain a robust ASW posture in the post Cold War security environment.

This fundamental reality of naval warfare creates a series of challenges for the US Navy. The biggest challenge is to explain the threat posed by even small numbers of modern non-nuclear submarines.

ASW practitioners instinctively understand this threat but often founder in making it credible to a wider audience in comparison to the Cold War threat, which consisted of more than 100 Soviet nuclear submarines.

The key variable left out of this comparison concerns the willingness of the United States to incur costs in a conflict.

Under such circumstances, even one opposing submarine has the capability, if unchecked, to frustrate the Joint Force Commander's intent.

Another challenge for the Navy is to communicate to its consumers in the other services how different ASW is from other warfare areas.

Even when successful, as the Royal Navy was in the Falklands, ASW is usually a protracted, platform intensive exercise in which the threat is not eliminated but simply held at bay.

The trend towards net-centric warfare schemes in support of the strike, expeditionary, air, and missile defence warfare areas needs to be leavened by the potentially countervailing demands of the antisubmarine warfare area.

Indeed, better coordination among the platform communities is important in order to limit the political costs that can occur when multiple constituencies vie for the same, limited resources.