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THE LOW FREQUENCY ACTIVE SONAR: A NEW LOOK

Nader Elhefnawy holds a BA in International Relations from Florida International University and is presently a doctoral student in Literature at the University of Miami. He has previously contributed several articles to THE SUBMARINE REVIEW.

The end of the Cold War has changed the orientation of thought on submarine warfare from global, high-seas conflict to regional conflict along the world’s littorals. 1 For instance, where the Seawolf class submarine was designed to hunt Soviet ballistic missile submarines, the Virginia class vessels were designed with an eye to shallow-water operations. Anti-submarine warfare has evolved similarly, the T-AGOS class sonar vessels currently being slated for equipment with a Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) for detecting quiet diesel-electric submarines in acoustically complex shallow-water environments. The Navy’s argument for the system is that the LF A would give it the capability to locate submarines in these environments while they are sufficiently distant for its units to react effectively. However, the LFA sonar array generates a pattern of very loud noise reaching out to a hundred miles from the source, which has created concern over its environmental effects, particularly on marine mammals like whales.

Consequently, a coalition of environmental groups led by the Natural Resources Defense Council sued the Navy and the National Marine Fisheries Service in Federal court in August 2002 to block the use of the LFA. Such claims, of course, can not and should not be taken lightly, but this article will not attempt to decide their validity. Its purpose instead is to examine facets of the issue that have been previously unexplored, some of which are hinted at by the recent lawsuit and are generally a consequence of this system, which must be seen as unique because of its intense, wide-area effects. Irrespective of the system’s ultimate environmental impact, questions are raised about existing maritime law which can affect American relations with states friendly and otherwise .

EEZs and LFA Usage

The 1982 United Nations Law of the Sea Convention gives states the authority to regulate the maritime environment not only inside their territorial seas but their economic exclusive zones (EEZs), extending two hundred miles out from their shorelines. Specifically, they enjoy sovereign rights over the use and conservation of the natural resources in these waters under Article 56 of the Convention. 3 Sovereign rights over natural resources would extend to the discharge of “substances or energy” into the marine environment, a category that can include the sound produced by active sonar. This remains the case regardless of the environmental consequences of that sound, though municipal environmental law may present another complicating factor. In other words, using an active sonar within another state’s EEZ may be legally comparable to flying through its airspace, and the system’s sheer power will make it easy for states to detect the use of this sonar, and more likely to forward such a claim.

Sovereignty aside, the exploitation of the seas is a matter of growing economic importance, and a principal cause of naval skirmishes in recent years, in the South China Sea and off the Korean peninsula to name two examples. Should Low Frequency Active Sonar imperil or merely be seen as imperiling the delicate ecological balances on which fishing or other economic activities depend, other states will have greater incentive to demand that LFA not be used inside their EEZs. Depending on how these areas are measured, they could comprise more than a third of the world ocean, meaning that the LF A may end up being usable in consider-ably less than the seventy-five to eighty percent of the oceans presently envisaged. Given the long range of the LFA, the system may become unwelcome in areas adjacent to EEZs, which would make it usable in an even smaller portion than the two-thirds presently outside state control. Even in those waters where the LFA does not outright become off-limits, its use could come to depend on the approval of states sovereign over the affected waters, permission which may often be denied even by friendly governments.

Since the sonar’s purpose is to hunt submarines in littoral areas, this would mean the system’s being politically neutralized in the areas that are the justification for its existence. It could also mean the introduction of additional frictions into American relations with other states, regardless of the ultimate legal status of LFA usage. Difficulties of the sort the United States experienced with New Zealand in the 1980s when it banned nuclear-armed and nuclear-powered vessels from its ports, and was ultimately relieved from its defense obligations under the ANZUS (Australia-New Zealand-United Statt: s) Treaty, could be repeated in instances.

The Balance of Power

The avoidance of such legal and political complications aside, the United States may have a more direct security interest in supporting, or at least not opposing, an international regime of sorts forbidding the use of such sonars. The T-AGOS vessels towing the SURT ASS LF A sonars are not without their shortcomings, chief among which is their physical vulnerability, a deficiency which helped to kill the arsenal ship in 1997.

The fact that these ships are being intended to deploy active sensors off the littorals of potentially hostile states dramatically increases the danger to them over what they saw in the Cold War period when they were passively tracking Soviet submarines in the open ocean. The reality is that any opponent sophisticated enough to operate a modern submarine in a littoral environment in the optimal manner that makes them so stealthy as to justify LFA will also have the capability to threaten an unarmed, offshore vessel with air, missile and surface assets. Given the widespread impression that these ships are uniquely valuable, a potential adversary would think such an action well worth the effort, though it must be noted that these vessels are expected to operate in conjunction with carrier groups.

More importantly the United States is the world’s premier submarine power and for that reason may need to display more circumspection about the introduction of anti-submarine technology into use than any other power. The sheer power of the low frequency active sonar creates the risk that it will interfere with the operation of other nearby acoustic anti-submarine sensors, and the operations of American submarines in the area. While the growing capacity of information technology to coordinate naval operations above and below the waves may mitigate such problems, the LFA will make for a far more complicated battle environment, posing potential risks for American units that do not appear to have been given much consideration to date.

It also should not be assumed that the technology will remain an American monopoly. Technology cuts both ways and it is necessary to remember that many, perhaps the majority of the submarines operating in a littoral zone in any likely conflict will be American submarines against which the active sonar described here could be turned. While this is not normally a question, it is one because of the political controversy surrounding the system, which raises the issue of its proliferation and in turn raises yet another question. Is the advantage gained by the anticipated heightening of American anti-submarine capability greater than the disadvantage incurred by having the same type of sensor trained on U.S. subs, particularly by an opponent unwilling to respect any restriction on usage to get the maximum possible benefit from active sonar? Given the offensive bent of submarines, and the defensive bent of anti-submarine technology, the net outcome of such a development may be the disadvantage of the U.S. submarines performing missions in the littorals for military and political reasons.

The growing demand for submarine reconnaissance and maritime interdiction operations, the rising impon of special forces actions, and the increasing capacity of submarines to function as cruise missile platforms all suggest that America’s reliance on submarines is likely to grow in the foreseeable future.5 No other state can claim a comparable reliance on its submarine force, if only because they continue to lack many of these capabilities. While it is necessary, of course, for planners to err on the side of caution, unrealistically high assessments of an opponent’s strength can lead to poor strategic and tactical choices as much as underestimation. There may be over two hundred submarines in the navies of non-allied nations by some counts, but the number deployed operationally, in any particular region at any given time, let alone the number that may be faced in any foreseeable scenario, will be far smaller. Such submarine-counting also neglects qualitative differences, putting a North Korean Romeo class vessel on a par with an American Los Angeles or even Virginia class boat in terms of not only technology but infrastructure, training, logistics and readiness generally, all areas where the United States enjoys a vast margin of superiority.

The overwhelming quantitative and qualitative U.S. superiority in major weapons systems both above and below the waves, and in the industrial capacity that produces both, may make an asymmetrical approach by which other states counter the United States through an emphasis on submarines untenable for decades to come. The result is that likely opponents will have more to fear from American submarines than they can hope to gain from acquiring a submarine fleet of their own. Such capability as they will have will be one for very expensive “underwater terrorism” rather than a capacity for attaining a favorable decision in a naval conflict. The prospect of underwater terrorism can not be easily dismissed, but given the extraordinary technical and economic demands submarines make on a military, there is also a risk that the threat will be overstated in the case of cash-strapped or underdeveloped states.

Recognizing this fact such states may opt for the easier path of the defensive rather than the offensive by seeking anti-submarine systems to prevent access to their coasts. 7 This could well include other states deploying Low Frequency Active Sonar systems of their own. Such a system would be cheaper and simpler to acquire and operate than a submarine, and so perhaps the more effective approach to coastal defense. 8 Installed in an oil rig or other relatively survivable offshore facility, it could greatly complicate the penetration of American submarines into their waters, particularly if the facility were configured as an anti-submarine command-and-control system capable of coordinating other assets. Also unlike the United States, which with its global responsibilities may find greater cost and smaller advantage in deploying the LF A than has generally been appreciated, the naval commitments of these other states will be limited to their own waters and so present fewer such legal or political difficulties. Rogue states without regard for world public opinion would enjoy a greater advantage still.

The low frequency active sonar must be regarded as a unique system because of its power, which may mean legal and political complications quite separate from the environmental issues already widely discussed, as well as a relatively convenient way for rogue powers wishing to keep the U.S. fleet at bay to raise the risks for American submarines in their littorals. By making it politically more difficult for such states to also acquire and deploy low frequency active sonars, the United States could retain and extend its advantages not only in submarine, but anti-submarine, capability.

American anti-submarine efforts are also premised upon a broad spectrum of technologies rather than any single detection system, a spectrum that likely regional opponents would be much less able to pursue. Barring the use of this single type of asset will therefore be costlier to their littoral warfare capabilities than those of the United States. Even were this not the course taken, however, a greater emphasis on other sensor types with less baggage, such as passive sonar, magnetic and infra-red, and on improving data collection from sensors of all kinds through the continuing development of infrastructure, appear to be more promising solutions to the detection problems posed by littoral environments.

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