Naval Doctrine Command

1 May 1998

Table of Contents

Executive Summary


Anticipated Battlespace and Adversaries "The ASW Challenge

Littoral ASW

Littoral ASW into the 21st Century

Recommendations and Epilogue


List of Figures

Figure 1. Mission Support Pyramid
Figure 2. Strategic Foundation
Figure 3. The Relationship of ASW to the Tenets of Joint Vision 2010
Figure 4. Asymetric Threat Risk Analysis
Figure 5. Littoral ASW Mission, Operational tasks and Infrastructure Tasks
Figure 6. Defense-in-Depth Options
Figure 7. Future Missions, Operational Tasks and Infrastructure Tasks

Executive Summary

"He who will not apply new remedies must expect new evils." Sir Francis Bacon

Purpose and Scope.

This paper provides a Fleet perspective for development of future operational capabilities for littoral anti-submarine warfare (ASW). It is an ASW warfighting concept. It is directed at flag and civilian leadership within the DoN, scientific, technological and acquisition communities to provide Navy ASW goals. These goals must then be assessed, modified and attained through a concept implementation process.

This concept reflects the fusion of both the operational and technical communities to define future operational methods and capabilities to conduct successful ASW. It recognizes that new warfighting capabilities result from the co-evolution of innovative technology, doctrine and training.

The description focuses on operations about 15 years from today (years 2010 to 2015). This time frame required the analyses to consider present-day technology, operations, and scenarios, but permitted inclusion of new concepts, capabilities and likely mandates. It looks beyond current Navy plans and the program of record, focusing on future operational capabilities required by the U.S. Navy to enable and support future joint operations beyond 2010.

Many ASW capabilities and assets are applicable to both littoral waters and the open-ocean. The challenges of each area are different, and in some cases, require unique capabilities. This paper limits its discussions to the littoral environment, forces and operations. However, the narrow scope of this concept is not intended to imply that open-ocean ASW is a solved problem. Open-ocean ASW remains a difficult task with many issues in common with littoral ASW and also many issues unique to open-ocean operations.

The concept focuses on those capabilities required by the US Navy to conduct littoral ASW missions. Complementary capabilities required of allied or joint forces are not detailed. When mentioned, specific systems are described only to help illustrate an idea or the effect a system’s capability might have on the ASW concept described.

Littoral ASW

Littoral ASW operations protect naval forces, commercial and logistics shipping from enemy submarines, and thereby enable naval forces to project power ashore, conduct strategic sealift operations, and control or interdict sea lines of communications (SLOCs) that affect littoral objectives. In the context of US joint force operations, successful littoral ASW clears the undersea battlespace of hostile submarine influence and permits US and combined forces to maneuver at will to best employ their assets at the time and place of their choosing. In limited regional conflicts, the loss or crippling of a key ship could unacceptably disrupt joint or naval force operations. The political realities of many regional conflicts could allow an adversary to equate a stalemate at sea with a strategic victory.

The ASW systems and practices employed in the open-ocean are not necessarily those that work best in littoral waters. Littoral ASW requires a complementary set of capabilities that address the special circumstances of naval operations in littoral waters. The littoral battlespace’s complex, noisy environment undermines the effectiveness of acoustic ASW sensors optimized for deep water, open-ocean ASW. In this environment, increasingly quiet and capable submarines operated by potential adversaries further erode the position held by open-ocean ASW forces. Quiet threats operating in harsh environments increase the utility of non-acoustic and active acoustic sensor systems. To be effective, sensors must be able to automatically adapt to the environment.

Principles of Littoral ASW

  • Understand and prepare the battlespace for joint force's maneuvering upon the sea.
  • Deny enemy submarines influence in the joint operating area.
  • Prosecute enemy submarines as close to their operating bases as possible.
  • Emphasize integrated information connectivity and flexibility at all levels.
  • Adapt sensors and weapons to the operational environment to optimize effectiveness.

The accelerating rate of technological innovation gives increasing advantages to the navies that most quickly introduce appropriate new technologies into their fleets. This introduction process must be rapid, focused and include all aspects of procurement, training, operations, maintenance and support infrastructure. Close coordination of US Navy ASW concepts, programs, systems and operations will optimize the ASW force’s capability in a period of declining resource allocations.

Coordinated, Multiplatform ASW Concept

Littoral ASW operations during periods of armed conflict should exploit defense-in-depth to maximize the flexibility of joint forces. These operations could occur against enemy submarines at their base (preemption), as they exit or return to port (port interdiction), as they approach the area of operations, threaten littoral sea lines of communication (SLOCs), and within the area of operations.

Preemption prevents the employment of enemy submarine forces by neutralizing submarines at their piers, and by attacking fixed support facilities essential to the effective employment of submarine forces. Because preemptive attacks deny adversary forces the ability to maneuver, preemption, if politically permitted, may offer the best balance between ASW effectiveness and economy of force.

Port interdiction offers opportunity to engage, monitor or tag adversary submarines before they can submerge. However, harbors and harbor entrances are particularly demanding environments for the employment of ASW systems. Thus, coordinated employment of appropriate sensors and weapon systems will be required to achieve optimal effectiveness in port interdiction operations.

Outside the area of operations, ASW forces have the flexibility to exploit maneuver and mass to defeat adversary submarines. This permits commanders to employ techniques such as barrier defense, defensive minefields and denial of logistic support opportunities. It also permits placing ASW forces at points along the threat axis where sensors and weapons may enjoy the benefits of more favorable environment, resulting in a higher probability of success.

SLOC protection may require ASW forces to protect large areas while placing a special premium on the effectiveness of coordinated ASW operations near chokepoints. These areas have noisy, cluttered environments that geographically concentrate both friendly naval forces and adversary submarines.

Within the area of operations, finding and neutralizing enemy submarines will demand the assignment of significant forces to the ASW effort. Effective operations in the area of operations require numerous, coordinated ASW assets. Mêlée and flaming datum situations will fully stress our ASW systems.

Each scenario relies on coordinated, multiplatform ASW. The range of possible threats places a premium on timely and accurate information about adversary submarine operations, thus ASW commanders will require a responsive command and control architecture to effectively coordinate their forces. The concept requires commanders to balance the operational capabilities of available assets with mission objectives. These operational capabilities will depend on the assigned forces’ combat systems and materiel, training, doctrine, organization and leadership.

The mission objective of forward operating area ASW battlespace dominance directly supports the national military strategy. Successful achievement of this mission rests upon properly shaping and employing the manpower and equipment provided to implement the national military strategy.

Capabilities and Constraints

Task Imperatives. To conduct littoral ASW, naval forces must be able to:

Programmatic Realities. Continuing ASW program budget constraints, and the increasing capabilities of the evolving submarine force threat, place additional imperatives upon all ASW programs. ASW programs must:

Within these constraints and in the most challenging ASW operations, coordinated, multiplatform ASW operations promises to provide the capabilities required of littoral ASW.

Coordination and Command, Control, Communications, Computers and Intelligence (C4I). Coordinated, multiplatform operations ensure the most effective sensors and weapons are used when and where they are most needed. Continuous awareness of the common tactical picture among ASW assets is essential to this concept. Assured C4I connectivity enables ASW forces to respond to fleeting contacts, integrate their collective knowledge to form this common tactical picture to best exploit their weapons’ capabilities.

All sensors, including those not historically associated with ASW, must be integral to the C4I network. For example, surveillance systems previously associated with only strategic indication and warning missions must also provide tactically useful information directly to ASW platforms.

Materiel and Weapon Systems. Optimization of materiel assets capable of capitalizing in a "plug and fight" environment is essential to coordinated, multiplatform ASW.

Coordinated, multiplatform littoral ASW draws from the experiences and knowledge gained through open-ocean ASW. When appropriate, the equipment and practices employed in open-ocean ASW must be used in littoral operations.

The best sensor and weapons systems are those operated
outside the target's sphere of influence on our forces.

Training and doctrine. Effective training and doctrine are required to achieve the close coordination and responsiveness necessary for successful littoral ASW. The training must be challenging and focused to develop and maintain ASW expertise. Many area specific, political, warfighting and environmental differences make littoral ASW noticeably different from open-ocean ASW. This mandates littoral ASW doctrine be continually developed, evaluated, revised and promulgated as the Navy’s experience, systems, operations and goals evolve. Successful execution of both new and existing doctrine requires proper training to develop and maintain proficient operators.

(New Equipment) x (Zero New Doctrine and Training) = ZERO

Organization and leadership. The organizational leadership structure required to support littoral ASW may also require modification from that of parallel open-ocean ASW structures. Organizations must be able to work towards the visions of the leaders while maintaining or improving an operational capability.


Conclusions and Recommendations

This concept addresses the capabilities required to conduct successful ASW and broadly defines the enabling capabilities required to achieve the mission objective of forward operating area ASW battlespace dominance. Much innovation is required to attain this goal of conducting fully integrated, multiplatform, ASW concurrently with power projection and other military operations. The limitations of current day systems and doctrine restrict today’s ASW to platform-centric operations conducted as an enabling phase distinct from the main warfighting effort to prevent unacceptable losses to enemy submarines.

As improved equipment and updated tactics, techniques and procedures are developed, the state of ASW will evolve from the sequential, platform-centric reality of today to the concurrent, network-centric construct of the future. To accomplish this evolution, we must:


Anti-Submarine Warfare:"Operations conducted with the intention of denying the enemy the effective use of submarines." Joint Pub 1-02

Battlespace: "All aspects of air, surface, and subsurface, land, space, and the electromagnetic spectrum that encompass the area of influence and area of interest." NDP-1

Battlespace Dominance: "The degree of control over the dimensions of the battlespace that enhances friendly freedom of action and denies the enemy freedom of action. It permits power projection and force sustainment to accomplish the full range of potential missions." NDP-1


"A notion or statement of an idea, expressing how something might be done or accomplished, that may lead to an accepted procedure." Joint Pub 1-02

A concept is a recommended solution to an opportunity or challenge. "Concepts provide the foundation for evolution." Joint Vision 2010

Littoral: "Those regions relating to or existing on a shore or coastal region, within direct control of and vulnerable to the striking power of naval expeditionary forces." NDP-1

Littoral Anti-Submarine Warfare: as used in this paper, refers to issues pertaining to the neutralization of the littoral submarine threat.

Undersea Battlespace Dominance: The ability to deny threat submarine operations in the joint forces maneuver areas and their associated sea-based logistics support."

Undersea Warfare: "That segment of naval warfare which involves sensors, weapons, platforms, and targets in the subsurface environment." NWP 1-02





This paper provides a concept for conducting anti-submarine warfare (ASW) in the littorals. It broadly defines the capabilities necessary to conduct successful littoral ASW operations in the 2015 time frame. The discussion provides a framework for the actions and innovations of many people whose work will turn this evolving concept into tangible changes in organization, training, materiel and weapon systems, doctrine, and leadership. It is directed at the flag and civilian leadership within the DoN, scientific, technological and acquisition communities. The littoral focus of this concept is not intended to imply that open-ocean ASW is a solved problem. Open-ocean ASW remains a difficult task with many aspects common with and some unique from littoral ASW.


ASW, as defined in Joint Pub 1-02, is "operations conducted with the intention of denying the enemy the effective use of submarines". ASW is a subset within the broader Navy definition of Undersea Warfare, defined in NWP 1-02 as, "that segment of naval warfare which involves sensors, weapons, platforms and targets in the subsurface environment". ASW is one of the warfare areas crucial to the success of any military operation that includes the use of maritime forces and logistics.

The ASW systems of today have been optimized for operations in the open-ocean environment. The limitations of these systems currently restrict ASW to small areas centered about the individual platforms conducting the operation. Protracted sanitization operations, requiring a significant operational pause in advance of the main military operation are required to prevent unacceptable losses to enemy submarines. As warfare moves into the 21st century, ASW must evolve from the platform-centric, sequentially phased reality of today. Advances in technology, tactics and doctrine will produce an integrated, network-centric architecture capable of denying enemy submarine influence throughout any joint operating area concurrently with power projection and other military operations. The transition to network centric ASW requires a plan that provides a path from current and near-term capabilities through mid-term improvements, to the far-term to achieve the necessary future operational capabilities.

National Objectives.

As a maritime nation, the United States has continuing vital economic, political, and military interests around the globe. Forward...From the Sea describes US naval forces’ enduring contributions of strategic deterrence, sea control, maritime supremacy, and strategic sealift in support of the national military strategy. It points out the unique contributions of naval forces to power projection and forward presence. Figure 2 describes how national objectives form the basis for the translation of ASW missions that ultimately establish manpower and equipment requirements.

Joint and Naval Objectives.

The Navy’s essential contributions to the accomplishment of the national military strategy are defined in the core competencies developed by the Commission on Roles and Missions of the Armed Forces. While the Navy contribution to any joint military operation includes many things beyond the core competencies, these are the areas where the Navy has primary responsibility. The importance of successful ASW as an enabler to military operations is underscored by its inclusion as one of the four core competencies assigned to the Navy. Figure 3 illustrates how dominant maneuver, precision engagement, full dimensional protection and focused logistics are enhanced by information superiority to achieve full spectrum dominance. Successful ASW provides US and combined naval forces the ability to maneuver at will and protects seaborne combined forces and logistics critical to achieving the joint commanders’ mission. While successful ASW alone will not ensure successful completion of the mission, the disproportionate effect of a single enemy submarine may be enough to ensure failure. The reality or merely the threat of enemy submarine operations undermines the ability of joint forces to project power ashore. Some examples of the potential impact of enemy submarine operations include the loss of or delays in the arrival of:

Core Competencies

Core Competencies are the set of specific capabilities or activities fundamental to a Service or agency role. They define the Service's or agency's essential contributions to the overall effectiveness of DOD and its unified commands. The Joint Roles and Missions Commission determined in their May 1995 report "Directions for Defense" that the Navy's core competencies are:

  • Carrier-based air power projection
  • Amphibious power projection
  • Sea-based air and missile defense and
  • Anit-Submarine Warfare
  • The lack of tolerance for such losses could transform a rapid deployment or strike operation into a long, protracted evolution. As a result, the political realities of many regional conflicts could allow the adversary to equate a stalemate or operational pause at sea with a strategic victory. Future ASW capabilities must ensure that all power projection efforts are supported concurrently without the protracted, sequential ASW operations required today.

    Littoral ASW Objectives.

    In order for joint and/or multinational forces to succeed, littoral ASW must prepare the battlespace for other seaborne forces by denying enemy submarine influence in an operating area. Today this area is relatively small and centered about individual ASW capable platforms. As a result, ASW today focuses on clearing adversary submarines from the operating area before the arrival of the high value platforms and providing escort services to those platforms throughout the operation. This deliberate, sequential method of operation is contrary to goals of Joint Vision 2010 and Forward...From the Sea.

    Littoral ASW of the future requires the ability to deny adversary submarine influence over the entire joint operating area and supporting seaborne logistic routes without lengthy preparatory operations. ASW operations must be integrated with and conducted simultaneously with special force, mine countermeasure, theater missile defense, and high-paced naval power projection operations.

    Principles of Littoral ASW

    • Understand and prepare the battlespace for joint forces' maneuvering upon the sea.
    • Deny enemy submarines influence in the joint operating area.
    • Prosecute enemy submarines as close to their operating bases as possible.
    • Emphasize integrated information connectivity and flexibility at all levels.
    • Adapt sensors and weapons to the operational environment to optimize effectiveness.

    Anticipated Battlespace and Adversaries
    "The ASW Challenge"

    Diesel-electric submarines constitute a growing threat, one that can be difficult to detect and defend against in shallow water. Uncountered, these submarines can disrupt shipping and shut down vital sea lanes in littoral areas. Many navies now operate diesel submarines, and additional countries could well follow suit.

    William J. Perry, Secretary of Defense
    Annual Report to the President and Congress
    March 1996


    The submarine is a critical element of military strength -- for major powers projecting global might, for nations intent on projecting regional influence, and for any nation determined to defend its coast. Many countries consider submarines a cost-effective option for conducting a broad range of vital maritime missions. Adversaries are likely to employ submarines in any of the following missions:

    The asymmetric effects of some potential adversary warfighting capabilities are discussed in The Concept For Joint Operations, Expanding Joint Vision 2010, issued in May 1997. Figure 4 illustrates that while it is relatively difficult to develop a capable submarine force, once it is developed, as several potential adversaries have done, it poses a high threat to US forces. As a result, the US may find its forces deployed against a capable submarine threat in a variety of regions and environments around the globe. Because submarines may operate almost anywhere in the world’s oceans it is not possible to predict the battlespace exactly. The future threat will increasingly include diesel-electric or air independent propulsion submarine designs operated by potential adversaries for coastal defense and regional influence. Nuclear-powered submarine procurement by adversaries is expected to remain less common, but still poses a threat.

    The Environment

    Successful ASW operations in littoral regions will require the ability to adapt to the battlespace environment to maximize sensor and weapon performance. The environment exhibits greater variability in many littoral regions as compared to that of the open ocean. As a result, more parameters are of concern in properly characterizing and exploiting the environment in these regions. New ASW technologies such as electro-optical, laser, and chemical detection may require critical environmental support not available today. Environmental parameters that will be exploited in littoral regions include those:

    Understanding and predicting meteorological conditions are required to design and employ effective visible, electro-optical (EO), electric field (EF), infrared (IR), and electro-magnetic (EM) systems against these portions of a submarine’s signature.

    Within the nonhomogeneous littoral environment, understanding and adapting to a range of oceanographic conditions will be necessary. Critical environmental parameters include:

    The highly variable environment in the littorals directly translates to a complex ASW environment. Since acoustics will not be the sole detection mechanism, an environmental assessment will need to address the requirements of non-acoustic detection systems as well.

    Development of sensors and weapons that have the ability to dynamically and automatically adapt to the environment will require:

    Threat Assessment

    Although a submarine threat could come from any country that possesses at least one submarine and a desire to disrupt shipping, the growing threat is that more countries can readily acquire diesel-electric submarines. The worldwide trend is toward fewer, but more lethal submarines. While the total worldwide submarine order-of-battle is decreasing, the technology available in new and backfit submarine systems is advancing. On average, the cost of diesel-electric submarines has remained about the same, even though more advanced technology is being incorporated into each unit. Ten years from now, many potential adversary submarines will be equipped with state-of-the-art systems.

    Even without sophisticated technology, an adversary’s submarines may be able to perform their desired missions effectively. The mission success of a submarine depends upon several elements including stealth; mobility and endurance; sensor and weapon systems; operational proficiency; sustainability and maintainability; and command,

    control, communications, and intelligence. By making trade-offs between these elements, a threat nation can choose a combination of technologies that maximizes the "bang for the buck." For example, a nation concerned with a coastal defense role for its submarines may choose reduced mobility and endurance to gain enhancements in other elements, such as stealth and weapon firepower.

    "One who knows the enemy and knows himself will not be endangered in a hundred engagements. One who does not know the enemy but knows himself will sometimes be victorious, sometimes meet with defeat. One who knows neither the enemy nor himself will invariably be defeated in every engagement."

    Sun Tzu
    The Art of War

    A submarine force composed of a few relatively unsophisticated submarines is capable of conducting coastal defense or sea denial missions. Such a force can attack merchant and logistics shipping, conduct covert offensive mining, support special operations forces, attack amphibious ships, and hold regional naval forces at risk.


    Traditionally, a submarine’s ability to avoid detection is defined in terms of its acoustic signature. There are many sources contributing to a submarine’s acoustic signature. Machinery and other propulsion-related vibrations enter the water through the hull and radiate in all directions. The propeller resonates when turning, and cavitation (noise generated by bubbles collapsing) can develop. Additionally, the turbulent flow of water around the ship can excite the hull itself. Each type of noise has a unique pattern, which can differ with speed, depth, and water conditions.

    Quieting technologies continue to improve and are increasingly available to backfit older submarines. Hull coatings, improved propeller design, and quieted propulsion plant equipment reduce the submarine’s overall noise levels, especially at high speeds. Future incorporation of Air-Independent Propulsion (AIP), advanced batteries, and improved quieting measures will reduce the submarine’s vulnerability to acoustic detection even more. All these pose challenges for US ASW capabilities.

    In littoral regions, non-acoustic signatures will become increasingly important. A submarine exhibits various non-acoustic signatures, some of which are highly dependent on the submarine’s speed or depth. Chief among these are the magnetic and electrical fields generated as a result of the materials used in the construction of the submarine. Systems are currently available to reduce a submarine's magnetic and electrical signatures. Other non-acoustic signatures include the submarine’s wake, contamination within the wake from bubbles or chemicals, radar reflectivity, and the heat generated by the submarine’s propulsion plant.

    Mobility and Endurance

    Most potential adversaries will use low-speed, low-endurance diesel-electric submarines for coastal defense and limited regional influence. These submarines must periodically surface or snorkel to run diesel-driven generators to recharge their batteries.

    Earlier submarine batteries allowed slow-speed submerged operations for about 12 hours. In contrast, modern battery designs allow the submarine to increase its submerged endurance to as much as 3-4 days, and reduce the duration of its vulnerability when charging batteries. Advanced submarine battery designs are under development worldwide and could increase endurance up to 10-12 days of submerged operations.

    AIP technology is becoming more prevalent in the conventional submarine export market. Currently, only the Swedish GOTLAND class SS has an AIP capability. However, several other AIP designs, which include fuel cells, closed-cycle diesel engines, and nuclear battery chargers, have been successfully tested. The expense of these systems is considerable and only a small number of potential adversary navies will have this technology. Those nations incorporating AIP, however, will increase their submarine’s submerged endurance at slow speed by up to five-fold.

    For a nation with global or large-scale regional commitments, only nuclear-powered submarines have the endurance required for sustained long-range, high-speed operations. Relatively few countries have commitments that justify the expense, technical infrastructure, and political determination required to develop and maintain a nuclear submarine force. The nuclear submarine programs of countries like Russia and China will continue to produce capable nuclear submarines that will operate in both the open ocean and littoral waters.


    Rapid developments in computer and signal processing will result in increasingly capable sensor suites and tactical information systems with more automated functions, making it easier to detect, classify, and engage targets successfully with fewer operators.

    Future sonar suites include advances such as flank arrays, towed passive sonar arrays, real-time self-noise monitoring, and advanced signal processing capabilities. A low-end diesel submarine is likely to have a system equivalent to the present KILO SS class sonar suite, which has a capable array married to simple processors. With enhanced signal processing and displays coupled to the existing array, a low-end diesel submarine could become ASW-capable.

    Several nations have shown an interest in submarine-mounted non-acoustic ASW systems to complement their acoustic sensors. Such systems may appear in the market place at some future time, but none are currently available.


    Torpedoes increasingly have greater destructive power. Eight major producers offer at least 21 models of submarine-launched torpedoes for export. The spectrum of torpedo systems and technologies spans from simple straight-running weapons to wake-homing and sophisticated acoustic homing torpedoes. Heavyweight torpedoes, produced in 14 countries, are the principal submarine-launched weapons. Modern submarine-launched heavyweight torpedoes can literally break some warships in half. The proliferation of relatively inexpensive wake-homing torpedoes has put "fire and forget" weapons, which are highly lethal and difficult to counter, into the hands of any potential adversary’s submariners.

    Cruise missiles will further complicate the future threat picture. Russia, France and the US market submarine-launched anti-ship cruise missiles. Modern anti-ship cruise missiles can be difficult to detect and allow little reaction time. China is developing more advanced systems and is expected to market a submerged-launch anti-ship cruise missile after the year 2000. Although some of the newest missiles advertised for export could be launched from standard submarine torpedo tubes, others require specially designed launchers. However, even with anti-ship cruise missiles in their inventory, a country must also develop the over-the-horizon targeting architecture to effectively use the long ranges of these weapons. Future technologies that will be incorporated into cruise missiles include improved stealth, guidance systems, seekers, digital processing, and high-performance propulsion systems.

    Russia is currently the only country that possesses a submarine launched anti-submarine cruise missile capability. However, China has expressed an interest in developing its own submarine launched ASW missile and may be required to seek Russian assistance to accomplish this endeavor.

    Mines may be a particularly efficient method for an adversary to shape the battlespace. Minefields can restrict or deny the maneuverability of ASW forces, or create relatively safe corridors and areas through which enemy submarines can operate. Command activated minefields, turned ‘on’ or ‘off’ by the adversary as the conflict situation requires, may be particularly threatening to littoral ASW forces. Even relatively unsophisticated mines can cause extensive damage and are notoriously difficult to detect and remove. Most naval mines are dual-purpose, able to target submarines or surface ships. Mobile mines have a torpedo after-body used to propel them a considerable distance into shallow waters or harbors where they function as standard mines.

    Submarine-launched, anti-air missiles continue to be marketed. Systems presently available are limited to shoulder-fired variants, providing limited self-defense utility to submarines. Future systems will likely incorporate some form of internal mounting and fire control system to support submerged launch of these weapons.

    Command, Control, Communications, Computers, and Intelligence (C4I)

    The technology is available today for potential adversaries’ navies to develop low cost, commercial off the shelf (COTS) command and control architectures suitable to support operations within their littoral areas. Some potential adversaries will undoubtedly acquire such C4I systems by 2010. Today’s technology can support a third party command and control network through satellite or cellular networks. In the future, adversary nations may have access to satellite communications, over-the-horizon targeting nets, and satellite imaging.

    Operational Proficiency

    The operational proficiency of the potential adversaries’ submarine forces varies greatly. At present, Libyan submarines are inept and essentially non-operational, but the Indian and Chinese submarine forces are large with a core group of submarines that are relatively well maintained and operate routinely at sea.1 An Argentine Type-209 diesel submarine (San Luis) operated 800 NM from its base and made two attacks on British warships during the Falklands war.2 Faulted Argentine torpedo fire control maintenance caused these attacks to fail. San Luis demonstrated considerable proficiency, however, when it eluded the best ASW efforts of the Royal Navy. Over 200 items of ASW ordnance were employed against this one submarine, mostly against numerous false contacts.

    Clearly, the general operational proficiency of most potential adversaries’ submarine forces has not yet reached the level of developed countries, such as Russia and various NATO countries. Nevertheless, detecting and tracking a submarine in the littorals will remain a significant challenge.


    Littoral ASW operations will be conducted in a complex environment against a quieter, more capable submarine threat. These operations require the ability to adapt to the environment. Since a wide range of mission and cost options exist, submarines operated by different countries will have differing levels of proficiency, stealth, mobility and endurance, sensor and weapon systems, and C4I systems.

    Most potential adversaries will likely employ their submarines for coastal defense and regional influence, including sea denial and power projection. The littoral ASW battlespace of the future will be defined by these more capable threats operating in their littoral waters and strategically important choke points. It is important to remember that submarines are capable platforms and an adversary will not necessarily operate them as we expect.

    "...Submarines will allow the consolidation of Iranian Naval
    superiority in the entire Persian Gulf and the Strait of Hormuz."

    Admiral Shamkani
    Head of the Iranian Navy 1994


    Littoral ASW

    The primary focus of maritime forces has shifted from global to regional threats.

    Secretary of Defense Annual Report February 1996


    Missions and Tasks

    This section describes the missions and tasks of ASW as they apply to operations in the littorals.

    ASW Missions

    An ASW mission is a collection of tasks that support the Navy’s core competency of ASW. Each ASW mission is defined in a littoral context, and refers to current ASW capabilities. The ASW-related missions supporting forward-deployed, joint littoral warfare operations are:

    Inherent to each of these missions are the tasks associated with developing and maintaining battlespace awareness, to include environmental data, force locating data, and sensor/weapon performance predictions.

    Littoral ASW Tasks

    Littoral ASW tasks are actions required to successfully complete an ASW mission. These tasks are categorized as operational or infrastructure support. Operational tasks are accomplished through the application of sensors, weapons and decoys, using doctrine and tactics. Infrastructure support tasks are accomplished through a support system that develops and tests equipment, trains operators for their proper use, and provides associated operational and materiel support for their employment.3

    Operational Tasks. These tasks directly support an ASW operation and can be performed by any asset available to the ASW commander, including ships, submarines, aircraft, IUSS or other sensor systems, and many ASW weapons delivery vehicles.

    Infrastructure Support Tasks -- Infrastructure support tasks provide the foundation upon which the Navy builds and maintains operationally ready ASW forces:

    Figure 5 depicts the capabilities currently required to accomplish littoral ASW. The littoral ASW pyramid is based on the manpower and equipment provided to implement the ASW in support of the national military strategy. Infrastructure tasks enable operational tasks to be performed. The operational tasks provide the means to dominate the forward operating area battlespace.

    The large size of the ‘Training and Proficiency’ and ‘Manpower and Equipment’ blocks represent their importance to ASW. ASW cannot be done without properly manned, equipped, or trained personnel. No task will alone accomplish the mission. Mission success currently requires all tasks be completed.

    Littoral ASW Today

    "At the same time we address the problems of today,

    we must prepare now for tomorrow’s uncertain future."

    NSC National Security Strategy for a New Century, May 1997

    Since the significant impact of submarine warfare was first demonstrated during World War I, the goal of ASW has been to provide a seamless, in-stride denial of adversary submarine influence on political and military objectives throughout an area of interest. The nearly 100 years of incremental improvement in ASW has been matched by similar improvements in submarine capabilities. Today, ASW operations are inefficient as they are sequential, asset intensive and require operational pauses (sometime lengthy) to prepare a limited area to support naval force operations with acceptable risk. Thus, the submarine continues to be one of the most effective methods of influencing the Navy’s ability to execute operations from the sea.

    Furthermore, today’s ASW capabilities are optimized for the open ocean environment. As the mission focus moves to the littorals, the typically harsher environment limits the technical performance of existing ASW tactical sensors and weapons, making it difficult to detect, localize and neutralize submarines. Additionally, the lack of environmental data bases, remote and in situ sensors, real-time tactical sensors and weapons performance assessments that can automatically adapt to changes in the environment degrade an ASW commander’s battlespace awareness and ability to achieve battlespace dominance in the force operating area.

    Near-term and mid-term ASW capabilities in the current program of record reflect historical analysis and limited, incremental improvements in today’s systems to better match them to the operating environment. Most of these improvements focus on acoustically based sensor and torpedo systems and C4I related data processing. While these improvements may result in an improved ASW capability, they primarily support sequential operations.

    Only far-term improvements offer the potential to conduct effective ASW concurrently with a naval force’s primary mission. These improvements will only be achieved through the integration of innovative concepts into rigorous future operational capability planning. Areas requiring enhancement for successful littoral ASW have been identified by several studies and include:

    • Cueing (acoustic and non-acoustic)
  • ASW Combat ID/Undersea IFF
    • Acoustic and Non-Acoustic Sensor Systems
  • Coordinated ASW Tactics
    • Weapons
  • Coordinated ASW Training and Proficiency
    • Torpedo Self Defense
  • Environmentally Adaptive Capabilities for Sensors
    • ASW C4ISR Applications

    (Improvements in any or all of these areas will also enhance open-ocean ASW capabilities.)

    The Navy must develop a plan and investment strategy to transition ASW from current capabilities, through near and mid term improvements and far-term innovations, to achieve the future operational capabilities necessary to deny adversary submarines influence on maritime forces supporting joint or combined operations.

    New Technology Insertion. Current procedures for the introduction of new ASW technology inadequately address the issues generated by the accelerating rate of technological innovation. Specifically, present acquisition policies are too inflexible to permit the rapid insertion of the newest technologies on ASW capable platforms. These procedures result in ASW assets that are prematurely obsolete and significantly less capable than is technologically possible. Further, such delays in procurement generate no cost savings since the need for replacement systems is accelerated.

    ASW Community. Successful littoral ASW requires proficient operators employing effective and reliable sensor systems to detect, classify and localize submarines, and weapons capable of neutralizing threat submarines. Presently the US uses a variety of platforms for ASW and attempts to coordinate their efforts at sea such that each complements the actions of the other. A synergetic, systems approach in a Navy ASW strategy is needed to drive cross-community coordination and focus in the development and procurement of new or improved ASW capabilities.

    Close coordination of ASW concepts, programs, systems and operations promises to optimize the ASW force’s capability in a period of declining resource allocations. Coordination that focuses effort across platform and community resource sponsors could match improvements and tasks to platforms to optimize overall ASW capabilities.

    Realities & Imperatives

    The littoral ASW operational concept for the future must be focused to accomplish missions within the context of enduring realities:

    Given these realities, it is imperative that:

    The realities and imperatives are directly related. They provide the basis for measuring success or failure. Satisfying the imperatives will demand adaptation of existing resources and infrastructure along with rapid integration of new technologies. Cost efficiencies in existing programs are needed to make resources available for the coherent application of new technology to support this operational concept.

    Future Operational Concept

    Littoral ASW is an enabler for joint and combined force power projection objectives including operations other than war. A phased approach to the successful implementation of this operational concept requires dedicated peacetime action for deterrence and conflict prevention to enable a smooth transition from crisis to war, if required. Littoral ASW supports forces operating in the relatively confined waters of an adversary’s littoral to:


    Peacetime: Deterrence and Conflict Prevention

    During peacetime, sensors monitor environmental data in littoral regions of interest, adversary submarine capabilities, including force readiness, infrastructure and operating patterns. The peacetime sensor system must integrate remote sensors with national sensors to monitor locations and activities that identify a potential adversary’s submarine operations. Such assets conduct port surveillance, identify critical submarine infrastructure nodes, and contribute to the overall assessment of an adversary’s submarine capability. A combination of remote, autonomous and manned sensors will be used to detect, localize and monitor submarines that are underway. The goals of peacetime operations are to assess the threat and:


    A range of options must be available to conduct littoral ASW operations. These operations could occur against enemy submarines at their base (preemption), as they exit port (port interdiction), as they approach the defensive perimeter of the area of operation, and within the area of operation.

    As the focus of the ASW effort moves forward towards the adversary’s piers and support facilities, the number of assets required to neutralize adversary submarines decreases, while the difficulty in obtaining approval of the required ROE increases. A full range of options will provide the ASW commander the flexibility to accomplish his mission within the applicable rules of engagement.

    Preemption. The goal of preemption is to prevent the employment of enemy submarine forces by attacking submarines at the pier, and those fixed facilities that are essential to the effective employment of submarine forces. Preemption could include airstrikes with stand-off munitions, cruise missile strikes, Special Operations Forces, torpedo attacks, attacks by Unmanned Undersea Vehicles (UUV), offensive mining, and Information Operations (IO). Both the adversary submarines themselves and key submarine manpower and infrastructure elements such as munitions, command and control nodes, logistics depots and refit/repair facilities could be targeted. A combination of real-time remote sensing and a fully interconnected command and control network can provide operational commanders with refined targeting information, the ability to coordinate attacks, and accurate battle damage assessment.

    Rules of Engagement

    As is true of any military operation, the decision to emply preemptive attacks must be based on both political and military considerations. Prior to the commencement of hostilities, preemption may not be compatible with the strategic objectives of the National Command Authorities (NCA). Even during armed conflict, use of available weapon systems may pose an unacceptable risk of collateral damage. The NCA must reconcile the magnitude of the submarine threat to littoral operations with these considerations and appropriate recommendations from the military forces when formulating Rules of Engagement (ROE) for military commanders.

    Preemption exploits an adversary’s need to base submarine forces and their associated infrastructure at fixed geographic locations. Preemption may employ both lethal and nonlethal technology, and may seek to either deny adversary submarines the ability to operate or to deny them the stealth on which their effectiveness depends.

    The political implications of preemption dictate National Command Authority (NCA) level approval of the ROE and possibly the operations plan. Since preemptive attacks deny adversary forces the ability to maneuver, preemption may offer the best balance between ASW effectiveness and economy of force.

    Port interdiction. The goal of port interdiction is to neutralize enemy submarine forces after they sortie but before they leave their home port harbors. A secondary goal is to deny submarine forces already at sea the opportunity to resupply. Port interdiction includes attacking enemy submarines with torpedoes, UUV delivered weapons, Special Forces or offensive mines, or tagging them with covert or overt means to deny their stealth.

    Denying Stealth

    Submarines depend on stealth for both mission effectiveness and self defense. ASW forces perform "tracking" using acoustic sensors, non-acoustic sensors, and non-traditional techniques (such as tagging) in order to deny adversary submarines the opportunity to employ stealth. Overt tracking seeks to influence submarine operations by making it clear that stealth has not been achieved, while covert tracking seeks only to hold submarines at risk of destruction pending attack authorization.

    Commanders must balance these competing objectives. Choosing to track adversary submarines covertly limits the commander's choice of sensor and weapon systems while increasing the degree of surprise that can be achieved if destruction of the adversary submarine is subsequently authorized.

    The geography and bathymetry of harbor entrances often provide natural chokepoints that geographically concentrate the targets, facilitating detection and localization of underway submarines by autonomous, manned and remote sensing systems. coordinated employment of appropriate sensors and weapon systems will optimize the effectiveness of port interdiction operations with available forces.

    Due to the larger area involved, port interdiction requires employment of more assets than preemptive tactics to neutralize enemy submarines.

    ASW outside the area of operations (including SLOCs and Choke Points). Depending on the relative locations of port facilities and the area of operations, adversary submarines may need to transit between the two before being able to influence naval operations from the sea. Additionally, adversary submarines may approach the area of operations from other directions if they were deployed before the arrival of the naval forces or if third party submarine forces are committed to the conflict by a government sympathetic to the principal adversary’s goals.

    Conducting ASW at several discrete locations, such as chokepoints and SLOCs, or in a large area outside of the joint force maneuver area imposes a greater requirement for a robust, responsive command and control architecture to effectively coordinate the ASW forces. Additionally, a distributed network of environmental, tactical and national sensors must be integrated into this command and control architecture to provide a theater-wide ASW picture to the warfare commanders.

    Operating outside the area of operation offers ASW forces the flexibility to exploit maneuver and mass to defeat adversary submarines. This permits commanders to employ techniques such as barrier defense, defensive minefields and denial of logistic support opportunities.

    ASW in the area of operations. The mere threat of an adversary submarine operating inside the area of operations can adversely affect the mission effectiveness of naval forces. This potential demands the assignment of significant forces to the ASW effort to neutralize adversary submarine threats within the area. Conducting effective ASW within the maneuver area imposes the most pressing requirement for an integrated ASW system of sensors, weapons, information processing, and personnel to capitalize on moments of fleeting contact to neutralize or destroy enemy submarines before they can achieve their mission objectives.

    Figure 6 depicts the range of defense-in-depth options. Each option is enhanced by the synergistic combination of sensor and weapon capabilities achieved through coordinated, multiplatform ASW. This enhancement becomes increasingly important as a force multiplier to offset increasing asset requirements as the focus of the ASW operation moves towards and into the joint area of operation. Projecting the focus of ASW forward toward the enemy submarine’s bases will reduce the assets required to neutralize the enemy submarine’s influence. While economizing the force required, the forward projection of ASW reduces the warfare commander’s responsiveness to changes in the situation by driving the level of approval for the enabling ROE to higher levels of the chain of command. The political implications of preemptive tactics will most likely require NCA level approval and control of the ROE.

    Littoral ASW into the 21st Century

    "Undersea warfare remains a tough business where the only acceptable position is one of absolute operational primacy . . . We must ensure that the capabilities of our undersea warfare team are robust and effective against a full spectrum submarine threat which is increasingly diverse and technologically sophisticated"

    ADM Jay Johnson, USN
    Chief of Naval Operations, 1997

    Quoted in "Worldwide Submarine Challenges 1997"

    Operational maneuver at sea capitalizes on naval forces’ tactical mobility to thrust, feint, and drive home to a decisive point—often from a great distance. It uses the vast reaches of seas to stretch the enemy, forcing him to defend thinly or create gaps in his defenses. When necessary, maneuver at sea uses movement itself to control the depth of the battlespace, closing and opening the enemy as needed. The naval force circa 2015 will be a networked force with distributed sensors and weapons providing full battlefield coverage of both information and fires. Integral to this force is an integrated ASW system capable of locating and quickly neutralizing enemy submarines, as even a single unlocated submarine could result in a disproportionately significant operational impact. This ASW system is composed of a coordinated team of proficient operators, ships, aircraft, submarines, remote sensors, unmanned autonomous or remotely piloted vehicles with capable weapon and sensor packages. This system must be continually optimized to the environment to maximize its capabilities.

    This ASW system will be able to deny adversary submarine influence over the entire joint operating area and supporting seaborne logistic routes without lengthy preparatory operations. ASW operations will be integrated with and conducted simultaneously with special force, mine countermeasure, theater missile defense operations and high-paced naval power projection operations.

    ASW program constraints and the capabilities of the emergent submarine threat, levy on ASW programs additional imperatives. These programs must:

    Coordinated, Multiplatform ASW

    The challenges of the littoral environment and increasingly sophisticated submarine adversaries, coupled with the multiple, concurrent mission requirements, demand an ASW force that can respond rapidly and decisively. Funding constraints common to all military programs argue strongly for versatile assets that meet ASW commanders’ needs with the least expense. Coordinated, multiplatform ASW operations best meet these missions, challenges and constraints of littoral ASW.

    Coordinated operations ensure the immediate availability of the most effective ASW sensors and weapons for use when and where they are most needed. Continuous awareness of the common tactical picture among ASW commanders is essential to this concept. Effective C4ISR connectivity enables ASW forces to respond to fleeting contacts, integrate their collective knowledge and best exploit their weapons’ capabilities. Tactically significant information must be continuously distributed so as to:

    Multiplatform operations optimize available sensors and weapons, regardless of the platform from which they are employed. Enabled by a common tactical picture and robust C4ISR, ASW commanders will be able to employ detection sensors to best effect, ensuring enemy submarines are located reliably and quickly. Further, ASW commanders will be able to coordinate various sensor platforms to provide targeting information to the weapon system best able to attack successfully.

    Future Operational Capabilities

    The future operational capabilities described below are provided as examples and are a point of departure for further analysis as part of the concept implementation process. These analyses must:

    Materiel and Weapons

    Command, Control, Communication, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR). A survivable, real-time, joint C4ISR system architecture is central to coordinated, multiplatform ASW operations. This system must be capable of providing a clear, complete picture of the undersea battlespace. A commander must be able to assimilate the current status within a short time, one minute or less, of walking into the operations space. A Cooperative Undersea Engagement (CUE) system can provide an integrated picture of the battlespace to optimize the coordinated engagement of any undersea threat. This system must be based on a modular, common components for ASW systems that can be married with platform specific input/output front ends to maximize the commonality in a "plug and fight" environment. Key elements of the CUE system are:

    Environment. Detailed and thorough assessment of the battlespace environment can give warfare commanders a significant advantage. One component of this assessment may be provided by improved METOC tools, the other may be provided by "through the sensor" automated signal processing. US METOC advantages will aide in:

    Littoral ASW must incorporate search techniques, sensors and systems that exploit non-acoustic and active acoustic signals in addition to the passive acoustic signatures currently preferred in open-ocean ASW.

    METOC assessments and in situ analysis capabilities are required to support rapid appraisal and prediction of sensor and weapon performance. In sufficient numbers, remote autonomous sensors could complement the capabilities of tactical assets to collect environmental data. Remote sensors such as drifting data collectors, overhead systems, unmanned autonomous vehicles and expendable devices may provide a cost-effective means of increasing sensor coverage within an ISR network, even though few dedicated ASW platforms may be present. Real-time integration of all METOC sensor assets into the C4ISR architecture would provide an enhanced assessment of a region’s spatial and temporal variability. A complete future sensor system must be able to adapt itself to the changing tactical and environmental situation. For example, if local passive acoustic conditions deteriorate during a search, the sensor system might shift its processing power and sensors to concentrate resources on an alternative signal, for example, the EM signature.

    Rapid and accurate environmental assessment is important, but combat sensors and weapons systems must also be environmentally adaptive. These sensors should be able to sense the environment, collect the observations for input to models and plans, and adjust the system accordingly, either automatically or through operator interaction. Collected environmental and direct sensor response data will be processed with tailored computer models that consider the small-scale effects associated with near-shore, littoral operations. Coupling these computer models with tactical decision aides will enable intelligent systems to recognize patterns and present their information in ways most useful to the operators, for example through high-resolution, three-dimensional displays. In the cluttered background of the littoral’s environment, such processing and display methods gain increased importance.

    Cueing Sensors. Ideally, locating information from cueing sensors will be of fire control target solution quality. Attacks on enemy submarines require initial detection of the covert enemy as it operates anywhere in a large area (thousands of square miles). If US or allied naval forces maneuver or operate in dispersed formations (as they are likely to do), the required ASW search area will increase several-fold. ASW barriers designed to deny enemy submarines access to the area of operation rely on cueing to trigger tactical prosecution. Cueing sensors that pass information to other platforms for prosecution could also detect enemy submarines departing port. Alternately, the cueing sensor may set off an attack by torpedoes, mines or non-lethal devices.

    Cueing Technologies

    In addition to passive acoustic sensors, new alternative technologies may improve cueing capabilitites. These technologies include:

    Bio-Indicators -- In-water organisms, activated by a passing submarine, generate organic substances detectable by remote (perhaps spaceborne) sensors. Some organisms adhere to the submarine and continue to reveal its presence.

    Shallow Water Trip Wire -- A sensor or line of sensors (covertly) deployed across the enemy's transit routes could incorporate acoustic and non-acoustic sensors to detect and identify submarines. The real-time target information would be passed to other tactical platforms or could trigger (lethal or non-lethal) weapons against the sub.

    National I & W sensing systems' communications links to tactical commanders could be enhanced to ensure real-time detection of submarine movements from port are automatically relayed to ASW commanders. In many scenarios, real-time intelligence communication links could provide operating forces with positioning (and potentially targeting) data.

    Non-acoustic ASW sensors -- Continuing advances in non-acoustic signature detection and processing may permit satellites or long duration unmanned aerial vehicles (UAV) and unmanned undersea vehicles (UUVs) to find enemy submarines.

    Targeting Sensors. The range limitations of current sensor systems determine the employment of existing platforms. The harsh environment of littoral waters (when compared to deep, open-ocean environments) degrades the effectiveness of most traditional ASW targeting sensors. Successful prosecution of enemy submarines requires environmentally adaptive targeting and cueing sensors.

    Targeting Sensors

    Some new sensors, or improved methods of distributing existing sensors, may afford new capabilities and thereby affect littoral ASW concepts.

    Remote Unmanned Sensor Vehicles might be used to deploy sensors or active sources. These 'sensor dispensers' could operate in areas unacceptably threatening to manned platforms (e.g., close ashore). Aerostats, UUVs, USVs, or UAVs might be employed.

    Bi-static Resonant Acoustics -- Active acoustic sources may casue submerged submarines to reflect or resonate modulated frequencies back into the water column or to the surface. Advanced signal processing techniques may be able to recognize these acoustic signals (underwater ) or the resultant modulation of ocean surface waves (in spite of the action of wind and wave).

    Multiple, wide-angle electro-optic spectrum sensors may provide continuous 360o coverage, automated to increase detection confidence.

    Submarine tagging (see box on non-lethal weapons) can be employed to help friendly forces maintain continuous track of enemy submarines.

    At a harbor’s exit, acoustic targeting sensors may be least effective. Here a cluttered acoustic environment and generally poor sound transmission paths make sensors designed for deep waters far less effective. Shallow depths and shoreline restrictions may limit the maneuverability of the search and enemy platforms, further degrading sensor effectiveness.

    Along ASW barriers, targeting sensors optimized for littoral waters could be used to trigger activation of dormant minefields, or provide firing solutions to other weapon platforms.

    Weapons. Existing ASW torpedoes (designed for attacks in deep water) are generally far less effective in the shallower, coastal waters. Here the need for rapid, decisive responses with weapons almost certain to achieve their goals, argues strongly for new weapons systems.

    Lethal torpedo attacks are a required capability. Because contact with the enemy is often fleeting, these attacks will likely be most successful when launched as soon as possible. Closely coordinated ASW operations may increase the number of weapons that can be quickly targeted without creating mutual interference between weapons. This hard lesson was learned by the British in the Falklands crisis.

     Lethal Weapon Technology

    A number of emergent technologies may improve the probability of achieving "hard kills". Taken together they may provide future ASW forces with capabilities required to help meet this concept's goals. These technologies include:

    GPS accuracy in location and targeting. Integrating global positioning system (GPS) data into sensors and weapons could improve the effectiveness of both and reduce a weapon's dependence upon acoustics for final search. Additionally, it would increase the number and types of platforms that could deliver the weapons.

    High density fuels may reduce weapon volumes ten-fold, enabling smaller platforms (e.g., tactical aircraft) to deliver them, or increase the speed or range of traditional launch platforms.

    Miniaturization technologies, especially in electronics, could further reduce weapon size and weight. Miniaturization may result in weapons small enough to be used by any delivery platform. Smaller weapons might also enable dense attacks against fleeting contacts (similar to the 'hedgehog' ASW weapon).

    Advanced ASW mines, capable of telling friend from foe, and perhaps with ranges of more than two miles, could find wide use in anti-submarine barriers.

    Depth charges or bombs, incorporating the technologies described above, may find wide application and increased utility.

    Advanced power sources, including a new lithium ion power source, may overcome historic safety limitations of more volatile power sources.

    Modular weapon component designs may result in an ASW torpedo whose interchangeable parts permit it to be launched from varied platforms (ships, subs and aircraft).

    Together, some of these technologies might be combined in a new shallow water weapon.

    In addition to effective lethal weapons, ASW forces require non-lethal weapons to achieve mission kill in ASW scenarios that preclude the use of lethal weapons. Such weapons could markedly reduce or disable the adversary’s capabilities, or continuously alert friendly forces to his presence. Non-lethal weapons would provide the ASW commander additional options to deny adversary submarine influence on US or allied naval operations.

    Non-Lethal Weapons

    These may incorporate new technologies or resurrect old ones. These include:

    Submarine Tag -- A tag device, attached to a submarine's hull, reveals the submarine's position and thereby removes its chief warfighting strength, stealth. Tags accurate to GPS standards, and equipped with adequate communications transmitters, can provide position data at any depth. Clandestine tags would be known only to friendly forces. An overt tag's presence, though known to the target, could cripple the enmy commander's warfighting options and prevent him from threatening US forces until the tag can be removed.

    Sea Valve Bio-fouling -- Materials ingested into submarine ballast or drain systems (primary control system) while in port could foul sea and control valves and prevent positive depth control.

    Submarine screw and rudder fouling capabilities reduce the submarine's maneuverability or increase its acoustic signature, making it easily tracked.

    Snorkel mast accesses (exhaust or intake) could be disabled (open or shut), thereby forcing the submarine to the surface.

    Periscope damaging devices would restrict the submarine's ability to threaten surface forces and limit its maneuverability.

    Electrical distribution system or electronic system damage could be inflicted most easily when the submarine is on the surface or in port.

    Submarine nets, clandestine or overt, can restrict enemy submarine maneuvers from port, or through other restricted waters.

    Anti-submarine barriers can deny enemy submarines access to the area of operation. Coordinated and concentrated ASW markedly increases and focuses the probability of detection and neutralization, reducing the enemy’s ability to penetrate into the area of operation. Dense anti-submarine minefields, perhaps coupled with trip-wire sensor systems, may prove particularly effective in this role.

    Other Weapon and Materiel Innovations

    Some technical innovations may provide ASW forces with capabilities that could alter dramatically the dwarfighting concepts described in this paper. Because these capabilities will likely not be available until after the time frame of this paper, they have not affected the coordinated, multiplatform ASW concepts described. However, their potential effect on future ASW warfighting concepts warrants a brief discussion. It is prudent to remember that thwarting only one kind of weapon rarely guarantees success. Alternative enemy weapons could rapidly be applied to fill the void.

    Ship Torpedo Defense

    The basic premise of the multiplatform coordinated ASW concept described above assumes that enemy submarines pose significant threat to US naval forces and seaborne logistics shipping. If adequate defensive systems existed to counter an enemy's weapons, more forces would be available for other missions. Therefore, creation of effective anti-weapon weapons could make traditional ASW less asset intensive.

    Several defensive systems could contribute to such an anti-submarine weapon shield.

    • Torpedo Countermeasure Defenses -- improved torpedo detectors, countermeasures and tactics to counter torpedoes.
    • Anti-torpedo Torpedo -- an anti-torpedo weapon would destroy enemy torpedoes. Similarly, anti-torpedo depth charges may afford protection by destroying or disrupting incoming torpedoes. Advanced nets designed to fould incoming torpedoes may also contribute to this capability.
    • ASW Close In Weapons System (A-CIWS) -- similar in principle to the point-defense systems designed to protect surface ships from cruise missile attacks.

    Long Range ASW Unmanned Undersea Vehicles (UUV)

    A torpedo-like sensor/tagger with extended range, a UUV is operated remotely or autonomously to detect and tag submarines, perhaps with remote command & control. Operating autonomously for lengthy periods, UUVs would require high efficiency propulsion, maneuverability, sensors, stealth, data processing, and connectivity. Multiple UUVs would operate simultaneously in probable submarine operating areas, searching and assessing the environment. Collected data would be communicated at regular intervals or continuously.

    Organization, Training and Doctrine

    Littoral ASW draws from the experiences and knowledge gained through open-ocean ASW. When appropriate, the equipment and practices employed in open-ocean ASW should be used in littoral operations. Commonality reduces the costs (e.g., training, planning, efficiency, etc.).

    Nevertheless, the training and doctrine used to prepare for and conduct littoral ASW operations are substantively different from those used for open-ocean ASW. The force organization and leadership required to support littoral coordinated, multiplatform ASW may also require modification from open-ocean doctrine.

    Training. The close coordination and responsiveness required in this concept are achievable only with training. In conducting littoral ASW training, forces should:


    Technoligical advances will improve ASW training. Organizational changes may increase proficiency though faced with reduced total training funds.

    Common ASW displays, improved automated detection and classification processing, uniform graphic user interfaces and common hardware will reduce training, logistics and maintenance needs.

    C4I links between shore-based units and at-sea platforms will increase realism and the flexibility of training schedules while reducing at-sea operating expenses.

    Reachback capability provides real-time assistance to ASW operators when and where needed from a shore facility or onboard computer based "on-line" help.

    Doctrine. As with training, the development of doctrine must be integrated with the development and deployment of new equipment capabilities. ASW doctrine must be flexible enough to accommodate the many regionally specific environmental and political factors affecting operations in the littorals. ASW doctrine must encompass full use of all sensors with equal priority and skill. This doctrine must continually evolve to realize the improved capabilities offered by new and current systems. The development of doctrine, tactics, techniques, and procedures is an iterative process, where the path to success may be achieved through failure (trial and error). Timely dissemination of revised doctrine is essential to ensure that all parts of the "ASW System" can fully exploit these improved capabilities.

    Missions and Tasks for Future Littoral ASW

    As improved equipment and updated tactics, techniques and procedures are developed, the state of ASW will evolve from the sequential, platform-centric reality of today to the concurrent, network-centric construct of the future. The result of this evolution is depicted in the revised pyramid shown in figure 7. This pyramid reflects the ability to target directly from the initial cueing without lengthy search and localization phases currently required.

    This pyramid represents a greater than 25% reduction in the number of operational tasks required to accomplish the littoral ASW mission. This reduction will be made possible as significantly improved sensors, capable of providing weapons targeting quality information from the initial detection/cue, are developed. Integration of these sensors in a network-centric environment will eliminate or at least minimize the current requirement to further search the area identified by a cueing system to localize the submarine to attack criteria. As these time, asset and material intensive tasks are removed from ASW operations, the goal of concurrent, wide-area ASW will be achieved.


    Recommendations and Epilogue


    The goal for ASW in the future remains unchanged from the time the effectiveness of "modern" submarine warfare was first demonstrated during World War I. This enduring goal is to provide a seamless, in-stride denial of adversary submarine influence on political and military objectives throughout an area of interest. Despite nearly 100 years of improvement, today’s ASW operations remain inefficient, sequential, asset intensive and require operational pauses (sometimes lengthy) to prepare a limited area to support maritime operations at an acceptable level of risk. Continuing advancements in submarine warfare have maintained the submarine as one of the most effective methods of adversely influencing the Navy’s ability to execute operations from the sea.

    The concept focuses on the littorals since the typically harsh littoral exasperates the difficulties in conducting successful ASW. The principles developed are equally applicable to the problem of conducting successful ASW in the open ocean. The near-term and mid-term improvements to ASW capability in the current program of record reflect historical analysis and primarily represent incremental advances to better match today’s systems to the expected operating environment. While these advances will improve ASW capabilities, they primarily support only sequential operations.

    Far-term innovations offer the greatest potential to enable ASW forces to neutralize submarine threats throughout area of interest concurrently with other primary missions. These new ideas must be integrated into rigorous future operational capability planning.

    To evolve the state of ASW from the sequential, platform-centric reality of today to the concurrent, network-centric construct of the future, the Navy must:


    Our present system for procuring equipment and developing tactics on an individual platform basis was adequate during the Cold War era when we were countering the open-ocean, long-range, passively detectable submarine with independent systems that were thought to be effective against the threat. The very nature of conducting ASW missions with Cold War legacy systems afforded the ASW Commander long (e.g., hours and days) detection, classification, and tracking evolutions. This type of ASW was able to counter the threat at ranges well beyond their weapon’s capability. It provided the sensor operators and ASW commanders with ample time to derive target positions and fire control solutions. Now we are entering a new millennium, with vastly improved, diversified threats operating primarily in their local areas of influence. As more of the focus of the submarine threat moves to the littoral environment, a change in the ASW development and employment philosophy is needed. Nearly forty years ago in January 1959, the Chief of Naval Operations, ADM Arleigh Burke made the following comment concerning ASW:

    "There is no single or inexpensive answer to meeting this problem. It requires the close teamwork of all ASW forces--surface, subsurface, and air-- served by an effective worldwide network of intelligence and communications.... But technological breakthroughs are needed to solve the problems of detection, localization, and identification."4

    This statement remains true today. ASW remains a difficult task both in the open ocean and in the littorals. We must look at ASW as an overarching system, analyzed and procured with a mind toward overall capability vice that of individual platforms. The best ASW system is one that can detect, target and neutralize well outside of the adversary submarine’s sphere of influence on our forces afloat or ashore. The Navy’s current investment in legacy systems with extensive life cycle infrastructure support impacts the ability to infuse new technologies and ultimately limits system effectiveness. As a result, we sacrifice future capabilities necessary to effectively conduct ASW in order to support current operations. Previous conflicts have shown us that it is dangerous to sacrifice future capability for present operations. This lesson applies across the full spectrum of the littoral ASW... from acquisition to training, planning and operating we must prepare to fight tomorrow’s wars, not the last one.


    1 "Statement of RADM Thomas A. Brooks, USN, Director of Naval Intelligence, to the House Armed Services Committe," Department of the Navy(7 Mar 1991).

    2 Scheina, R. L. "Where were those Argentine Subs?," Proceeding of the U.S. Naval Institute 110(3), pp 114-120 (Mar 1984).

    3 The tasks listed have their doctrinal foundation in Joint Pub 1-02 (DOD Dictionary of Military and Associated Terms) and NWP 1-02 (Naval Supplement to DOD Dictionary of Military and Associated Terms).

    4 Burke, Arleigh. House Appropriations Committee hearing 86:1:1, 23 January 1959, pp. 661, 691