A condensed version of this article was published previously in The US Naval Institute ‘s PROCEEDINGS. It is republished in the complete version with permission of the Naval Institute.
The current policy of deploying submarines as a part of surface groups represents a return to the post World War I concept of employing submarines as scouts for the battle line, a tactic denounced by Nimitz when he was a Submarine Force commander in the 1930s and generally discredited during World War II. While this form of submarine employment has the promise of educating non-submarine officers to the value and utility of submarines, the intrinsic advantage of a submarine, an ability to operate with impunity in waters otherwise controlled by an enemy, is sacrificed. Using submarines in direct support of battle groups when facing the Soviet Union enjoyed the promise of good success. But even in that kind of operation the submarines were to serve as a spearhead during the advance of the battle groups into enemy controlled waters as an adjunct to their fast and far forward deployment that was the basis of the Maritime Strategy.
Most naval officers and analysts have viewed anti-submarine warfare, ASW, as a defensive operation since late in World War I. The convoy system, adopted in May 1917 after many losses, became the model for the mission. In World War I and through most of World War II the technologies and resources that could be brought to bear against the submarines made defending targets more efficient than attacking the aggressors. This defensive model remains the image of ASW in the eyes of many even though, by the end of 1944, offensive ASW was achieving far more contacts and sinkings than convoy escorts
Offensive ASW succeeded in 1944 and 1945 for two reasons. Interdiction of the approaches to France through the Bay of Biscay by radar equipped Maritime Patrol Aircraft made that passage a difficult and dangerous one for U-boats. German attempts to defend against this threat with anti-aircraft weapons were fruitless and the snorkel came too late to conceal transits through areas controlled by allied aircraft. At the same time on the open ocean, the Germans’ operational procedures and the supporting radio communications allowed the combination of direction finders and code-breakers to furnish the intelligence needed to dispatch offensive ASW forces, hunter-killer groups, to the locale of their targets. In both of these scenarios, the hunters became the hunted. By 1945 the losses to the German Navy were staggering; only one boat in five returned from patrol.
In spite of these successes, and of the clear successes in offensive ASW operations late in the Cold War, the practice of routinely assigning long-legged ASW assets to accompany Carrier Battle Groups and Expeditionary Strike Forces demonstrates that this target protection model has been resurrected as the major approach to ASW. But ASW assets that have more speed and stamina than the Group’s are wasted in attempts to sanitize the vicinity of high value targets. ASW platforms able to operate independently can be employed much more productively in offensive operations aimed at undersea control throughout the theater, not just the few hundred miles around the convoy, the transit lanes or the Sea Base.
This target protection mode is a faulty guide for operations against submarines today for a number of reasons. First, the number and capability of potential enemy submarines is lower than at any time since 1914. Second, while the value of today’s individual targets is high, they are fewer and faster: much more difficult to find and hit than those eight-knot, hundred-ship Halifax to Liverpool convoys of 1943. Third, because submarines attacking surface ships can lay well off their target’s track to launch missiles (though not torpedoes) from any azimuth, the area to be controlled in the protection model today is vastly greater than when submarines had to close their targets. Protecting a large and moving area is complicated by the limitations even moderate speeds impose on the effectiveness of active sonars and trailing antennae. Finally, the United States possesses an asymmetric advantage in capabilities and operational experience: if US forces are deployed early and employed offensively, they can be positioned to thwart or kill any submarines that may threaten US control of the sea.
While advocates must trumpet the potential dangers from the submarines of potential enemies in order to emphasize the need for continued expenditures for anti-submarine weapons, in reality today and for the forthcoming decade, the number of submarines that the United States is likely to face in any probable crisis is small and is made up of almost entirely of diesel electric submarines of limited endurance, low firepower and almost negligible agility. Few operate regularly or in realistic exercises. While each one could be a formidable threat if operated skillfully, submarining is not a casual skill like suicide bombing that requires only courage. As the Chinese demonstrated last year, when undertaken by the ignorant or unpracticed, submarines kill crews rather than enemies.2 While this balance of forces will not last forever, it is likely to hold true for the foreseeable future.
These small numbers are further hobbled by lack of robust sea surveillance and intelligence support. Because submarines have a relatively small visual and electronic view and a battery powered one has a minuscule radius of action, without intelligence to optimize positioning, any submarine’s ability to find or intercept targets is marginal unless at a choke point or at one of the ends of the transit route. Such intelligence is unlikely to be available to any realistic potential enemy in anywhere near a timely manner. Doenitz needed reports from the first sighting to concentrate his submarines against allied convoys-without these reports, encounters were singular chances even though the transit lanes between North America and Britain were well defined. In the American submarine campaign against Japan, most successes were along known narrow routes between the home islands and the conquered resources of Southeast Asia. Even so, radio intercepts then were invaluable in positioning submarines along their targets’ tracks.
This narrow aspect of submarine warfare is concealed during multinational exercises that include conventional submarines. Such exercises are structured to ensure that all players get an opportunity to engage. When the Australian submarines steam thousands of miles to participate in RIMPAC off Hawaii, they do not do so just to serve as targets. So the carrier has to pass through submarine infested waters lest the Chileans or Canadians go home frustrated and discouraged.
These necessary arrangements create attitudes and opinions that generate a false sense of the capability of the battery powered submarine to locate and attack these high value targets.
These disadvantages, small numbers, limited mobility and lack of intelligence support, represent opportunities best exploited at the outset of any conflict. Should an enemy succeed in deploying even a couple of submarines, no matter how well or poorly operated, into the broad ocean approaches to the battlefield, the efforts to find and defeat him will require weeks. In World War II, this meant the resources ratio between ASW and the submarine tipped from about ten to one to about a thousand to one. The answer then is to plan, prepare and practice for ASW campaigns that take place in enemy controlled waters as close to the opponent’s bases as possible starting long before any shooting is even contemplated.
This sort of offensive ASW requires more than warships and planes. An ASW campaign does not begin on day one of the battle or when the Fleet approaches enemy shores. Gathering intelligence, e.g. determining potential enemy dispositions, equipment, tactics and movements, and similar activities are essential precursors for an effective ASW campaign. While many of these are acknowledged roles for space based sensors and electronic surveillance aircraft, additional measurements are needed. The character of the ocean in the expected area of conflict is vital: the sound velocity profiles, the effect of fresh water contributions, the diurnal variations, the character of the bottom, and similar conditions that will determine the best depth to detect and avoid, the most likely locations for mines, the probable channels for dispersion and similar information. All of this must be gathered months and years before the likely conflict takes place. These are not measurements that can be determined by a glance at the chart.
By far the optimum tactic is to attack submarines while they are moored.3 Submarines that never get underway are only a drain on resources of their mother country, not a threat to someone else. With today’s precision-guided munitions, even the massive U-boat shelters still existing in the ports of Brittany would be of only marginal utility. The principal obstacle to such tactics comes from the political reluctance to start a conflict without an overt action on the part of the enemy. That precedent has been substantially eroded but not entirely removed by America’s preemptive actions in Iraq. Even in that conflict, permission to attack mine layers before they could get underway to Jay their mines never came in spite of Admiral Stan Arthur’s admonitions of that important lesson from the First Gulf War. Regardless of the likelihood of its political acceptance, the ASW intelligent commander should press for permission and be prepared to execute the tactic if allowed to do so.
If attacking the enemy in homeports is not allowed, tackling the opponent’s submarines as they deploy is the next best tactic. If shooting is not permitted, then escorting the enemy submarines from their diving point to their operating areas is certainly feasible. This requires ASW forces with long endurance to be present when the enemy submarine sorties. In the case of a diesel-electric submarine, the presence of an escorting maritime patrol aircraft or nuclear submarine will probably not be detected as the submarine transits to its operating area on the surface or snorkeling. If political authorities can be convinced to declare such maneuvers to be threatening before open war starts-as Roosevelt did in 1940 to U-boats west of Iceland -then such transits by potential enemies can be ended before they reach their initial diving points or operating areas with some degree of surety.
These sorts of tactics are possible because submarines operate in small numbers, ones and twos-not in dozens or fleets. Space based sensors allow submarines in port and underway to be counted. The result of this intelligence, the number of potential enemy submarines underway, is the entering argument for the plans of the ASW commanders. This knowledge Jays the basis for deployment of forces to intercept, locate and track such submarines as they depart their homeports. Past performance has shown that such tracking can be accomplished covertly even when the target submarine is a relatively fast nuclear powered submarine. To do the same for a diesel electric submarine that must transit to an operating area is an easier task.
In these circumstances, the word escort gets a new meaning-a platform accompanying the target submarine. The escort can emphasize the vulnerability of the escorted openly or randomly by non-covert activities, perhaps an occasional radar or active sonar emission. The unnerving effect of such an action may not cause the potential enemy to defect, but it will certainly heighten his nervousness and contribute to a feeling of low morale and potential disaster. Should a conventionally powered submarine shut down and go quiet as a result of such moves, it has effectively anchored itself in a spot that moves only a few miles a day, begins to use up battery capacity and is likely to remain stealthy only for as long as its captain is willing to forego aggressive action.
In the situation where shooting is not allowed and sufficient numbers of aircraft and submarines have not been deployed in a timely manner so that a one to one ratio of pursued and pursuer is not possible, the tradeoff between locating and searching becomes a command issue that is a theater wide one-not a local one. Not every enemy submarine needs to be trailed. Making the choices depends not only on the capability of the pursued and pursuer, but what other forces will be available and what other tasks portend. Only a theater wide view can evaluate these factors.
In the event that deployments have not been fore handed and the enemy submarines have left their homeports and headed for the open ocean without being intercepted, the ASW problem turns into a tedious search exercise, but not one that is unbounded. Knowing what submarines may be at sea, the geography involved, and the availability and capability of various search sensors, analysis can develop efficient search patterns. Mobilizing this information transforms the ASW search from random seeking of potential intruders to planned measures that narrow the locations of probable contacts. Such tools make offensive ASW more efficient as well as more effective than waiting for a flaming datum. They result as well in establishing locales that can serve as sanctuary for a Sea Base. Even with these tactics, however, if the enemy is allowed to deploy without detection or opposition, the resulting fray will be measured in weeks and months instead of hours or days.
On the offensive side of the equation, the technologies available for wide area search above and under the seas are vastly better than they were in the past-even as recently as 1990. Space based sensors, relocatable bottom mounted sensors, and wide area search sensors connected by long-range communications exist. When unmanned undersea vehicles become available as search devices the search rate for their mother ships will vastly increase. The command and control network for conducting theater wide offensive ASW was proven twenty years ago. The ability to concentrate forces, to direct searches to the most likely areas or contact, to reduce attention to areas of no interest, and to route ships around locations where diesel electric submarines have been observed, can all be accomplished easily from a theater wide vantage. While the tactical situation in an ASW attack is always in the hands of the on-scene commander, central direction is needed to coordinate forces earlier and over areas much wider than that area about which the Battle Group or Expeditionary Strike Group commander is concerned.
Regardless of the resources devoted, once an enemy submarine reaches the ocean operating areas, the time needed to detect, contain or sink it multiplies exponentially. If suspected of being located in the nexus of an operation area to be used by American forces, the enemy submarine will force delays on whatever operation is planned. The penalty for delaying the decision to undertake the ASW campaign, or to refrain from any early or provocative action is not simply a minute-by-minute tradeoff later, but extends by orders of magnitude the time that will have to be invested to neutralize the submarine threat If a decision maker understands that failing to attack an opponent’s submarines early results in a long delay in any further action, he may be more inclined to give a sympathetic ear to the suggestion to shoot them at the sea buoy.
Indisputably, the key ingredient in any ASW action is time. Having ASW assets deployed forward, operating under the authority of a theater command dedicated to ensuring access rather than handcuffed to a Task Group commander concentrating on a force movement and dependent upon a long logistics line, makes them an offensive ann long before hostilities are even contemplated. Obviously overwhelming superiority as envisioned here cannot be maintained constantly, so the ability to deploy fast is crucial. Both of these characteristics, endurance and speed, require long legs in each ASW vehicle. There must be enough vehicles to maintain the presence forward in areas of interest and concern, and enough space-based and wide area sensors to buttress them in the locating part of the problem. Maritime Patrol Air can play a part in these activities particularly with those diesel electric submarines that have gone stealthy in some spot. They cannot escape the MPA and once located are sitting ducks for the helicopters. Surface ships have a role where there are no air threats and only low speeds are required. But the offensive posture described here can be executed best by submarines.
The contribution of Maritime Patrol Air (MPA) in this design is vital but their search capability is limited by sonobouy inventories, their endurance and timeliness established by the proximity of an airfield and in those cases where ASW must be conducted in waters close to an enemy shoreline, the required mastery of the air may be problematical. However, MPA ‘s ability to quickly close a datum and to localize quickly in the open ocean is the best of any ASW vehicle. Radar flooding an area by MPA, manned or unmanned, discourages repositioning of a diesel electric submarine on the surface or snorkeling further inhibiting its mobility. The combination of MPA and nuclear submarines was proven to be a most effective combination in the past and with the demise of mid-range ASW aircraft on the carriers will be the only feasible forward combined arms ASW activity for the future. The combination of surface ships with tails and ASW helicopters can provide a measure of close-in defense for the surface group to which the an escorting submarine adds only marginally.
These are not the tactics of traditional escort-centric ASW. Nor are they the techniques practiced by destroyer sailors or helicopter pilots. The command and control processes for this type of a campaign are more related to strategic bombing than to historic maritime sea control. The precedent here is not Jutland or Midway, but the Japanese offensive against the Port Arthur in 1905. There torpedo boats and mines took Russia’s Asian Fleet off the board in the first actions of the war.
What are the immediate effects suggested by this analysis? The assignment of ASW vehicles, particularly submarines, as part of an expeditionary strike group or a carrier battle group is using tactics that were wrong fifty years ago, downplays our tactical expertise and fails to take advantage of our asymmetrical capabilities. Submarines, MPA and their supporting arms, TAGOS and intelligence assets, sensors and analysts, belong forward, operating independently in the areas of likely enemy submarine operations. The inclination to consider submarines as strike vehicles because they bring a substantial portion of land attack precision guided missiles into the theater warps the view of the commanders who employ this unique weapons system. Land attack missiles are a sideline for subs. Even though strike is a mission to which they bring special attributes of short time of flight, prolonged endurance and stealthy presence, if enemy submarines may be around and about, it is secondary. Other ways are available to deliver strike weapons, but only the submarines can do ASW forward before command of the air and sea is established.
The combination of fewer targets going faster as the objectives for few submarines of limited mobility and scarce intelligence changes the tactical equation. When highly mobile pursuers with unlimited perseverance are aimed against these submarines, ASW changes from a vast open ocean search problem to a timed operation governed by the cyclic requirements for the conventional submarine to charge her batteries. The freedom of action gained by sinking the mine layers before they could sow their weapons, by knowing the enemy submarines at sea are eliminated, or pinned down, or precisely located is incalculable. The Sea Base becomes secure: carriers can operate freely governed chiefly by the weather, surface warships can focus on AA W and strike, submarines not engaged in the ASW operations can be stationed forward with their missiles ready to engage targets needing rapid response and short time of flight, amphibious assault ships can proceed to the most advantageous positions, all with little or no regard for the subsurface threat. None of these things happen if the ASW campaign waits for the arrival of the fleet in the Sea Base.
This operational concept is not without precedent. In 194 l, unloosing US submarines had to wait until the battle line was demolished at Pearl Harbor. A year passed before the submarines developed what became their wartime Concept of Operations, deployment into enemy waters concentrating on Japan’s logistic lines. In today’s world, the National Command Authority, the Joint Chiefs and the other services, expect to have the initiative in ten days after the commencement of hostilities.5 If the enemy possesses any submarines, offensive ASW is the only way that these expectations might be meet. But such a Concept of Operations cannot be simply the subject of essay, conjecture or even war plans.
ASW is a team game and needs to be practiced-in war games as well as in operations and exercises and at all levels. Practicing offense now. not only provides training that will be needed in the future but also allows people to see the challenges of the environ-ment and tactics and the opportunities for exploitation. The reluc-tance to strike at probable mine layers in the Gulf Wars testifies to the difficulty of getting decision makers attention for what seems to be an exclusively maritime affair. Pressing decision makers for hard decisions in times of crisis is futile unless they have some previous basis in the issues. To obtain the ability to strike mine layers and submarines early in a conflict, the Navy as an organization must have not only experience in its own house and on joint staffs but also must build a foundation of understanding in policy makers at the upper levels of the Pentagon and the National Security Council. Such understanding can only be gained by involving these policy-makers and associated joint staff personnel in the games and exercises that demonstrate the benefits of early action as well as familiarizing them with the time lines involved with various component parts.
The proper ASW paradigm is not a random hunt over the broad ocean but it is not target escort either. Offensive, forehanded, aggressive, persistent attack, bringing all assets available to bear, is the characteristic of offensive warfare in anti-submarine warfare as in any medium. This offensive posture was the essence of The Maritime Strategy and meets the admonitions of Admiral Mahan,
“War, once declared, must be waged offensively, aggressively”