As the submarine force plots a course to the year 2000 and beyond, we should reflect on the tactical, strategic, and design factors which bear on the art of submarining. ADM Watkins, the CNO, points out that new submarine weaponry is opening exciting new roles. The TOMAHAWK cruise missile extends submarine standoff anti-ship attack range by a factor of four to five. A variation of this weapon will provide the submarine with a powerful land attack capability. Surprisingly, while we seek to expand the role of submarines, we have elected to concede to the Soviet Union a continuing three to one numerical advantage. This dichotomy will place considerable pressure on American tacticians, strategists, and designers to provide the ways and means by which we may preserve our edge in submarine warfare.
The qualities of our submarines are closely tied to their engines. This is not surprising, since any craft that seeks to break away from the surface of the earth is dependent upon unique engines. The lightweight gasoline engine was the key to the first practical aircraft. Gas turbine and rocket engines now extend our ability to operate above the surface of the earth. While far less spectacular than the gasoline engine, the electric storage battery provided the first practical means of operating below the surface without access to the atmosphere. The early art of submarining highlighted the conservation of battery energy. The nuclear engine has largely removed this energy constraint. We now analyze the value of expending energy (speed) rather than the value of conserving energy.
The energy revolution brought about by the introduction of nuclear power deeply affects submarine tactics, strategies, and design. Understanding of these effects is important in planning our future course. The discussion which follows will touch upon each of these topics.
Tactical Factors- The submarine found its niche in naval warfare as an inexpensive means to defeat the speed and firepower of surface ships. Its tactics are those of stealth; the submarine seeks to remain undetected by its opponent. Engine selection is critical. As the means of detecting naval targets advance, preferred engine characteristics change. Originally, the submarine remained submerged during daylight hours to avoid detection by the human eye. Electric propulsion served this purpose well, but submarine batteries required recharging. For many years, submarines would surface at night and recharge batteries by using diesel engines. The development and application of radar reduced the security of .surface operations. Introduction of the snorkel quickly followed. Although the modern non-nuclear submarine has not been defeated in combat, the added operational degrees of freedom offered by the nuclear engine have made nuclear propulsion the focal point of U.S. submarine development.
Americans have been quick to put nuclear engines to use. This exploitation has included increased speed, as found in our attack submarines, and increased firepower, as incorporated in our strategic submarines. We intend to develop nuclear submarines which combine both increased speed and firepower. This raises a fascinating tactical dilemma: submarines originally served as an inexpensive means of defeating the speed and firepower of other naval ships; will the submarine serve as an inexpensive means of defeating the emerging speed and firepower of submarines? Is a powerful submarine the best counter to the powerful submarine? Or, has the powerful nuclear submarine created a niche which remains to · be filled?
If submarines are to serve as the means to defeat powerful naval opponents (submarines, surface ships, and aircraft), they must continue to practice stealth. It is well known that the tactics of stealth in submarine warfare now emphasize one’s ability to hear and avoid being heard. The quiet engine/hull combination is important with respect to an ability to hear and an ability to avoid being heard. With considerable attention to detail, nuclear submarines have become progressively quieter. However, success in stealth is a relative matter.
In the world of underseas weapon systems we find two extremes, the mine and the nuclear submarine. The individual mine has no engine; it is the quietest weapon system. The nuclear submarine, with its powerful engine, may be quiet, but certainly not as quiet as a mine. The well-designed, constructed, and operated non-nuclear submarine fits somewhere between the nuclear submarine and the mine. It is of interest to note that ADM Doenitz, Commander of the German U boat service during World War II, recognized a tactical similarity between the non-nuclear submarine and the mine; he referred to the U boat as the “intelligent mine”. If stealth is the essential tactic in undersea warfare, the mine, the “intelligent mine”, and the nuclear submarine may all be key players. The niche that any of these stealth options may fill is dependent not only upon tactical qualities, but upon strategic usefulness.
Strategic Factors- Strategies deal with where, when, and how power is to be used in support of national objectives. In America, strategies reflect the hardware preference of the individual services. Over the years, we have seen the emergence of a bomber strategy, a missile strategy, a battleship strategy, a carrier strategy, and so on. The key to a strategy may be found in its planning assumptions. For example, we might select the following assumption made by Dr. Norman Friedman in testimony before the Senate
Armed Services Committee: “future conflict is likely to occur in unpredictable places, far from home, and probably without nearby bases”. This assumption creates a niche for the speed and endurance of the nuclear engine, whether in surface ships or submarines. Only such capabilities would allow us to respond to surprise conflict in remote corners of the world.
The foregoing planning assumption could be revised along the following lines: “future conflict will occur in predictable places, far from home, and with nearby bases”. This second assumption conforms precisely to the conditions existing at the time Japan attacked the United States in 1941 and when Argentina attacked the Falklands in 1982. Both events were predictable, since long periods of tension existed prior to the attacks and neither the Americans nor the British had committed sufficient military power to discourage the attacks. This second planning assumption does not argue for a specific hardware preference. There could exist a role for the mine, the intelligent mine, and the nuclear attack submarine.
If we are asked which came first, the planning assumption or the hardware preference, it is safe to assume the preference came first. This American pattern of behavior makes it quite difficult to introduce an innovative product in times of peace.
Design Factors- The naval designer seeks to create useful naval products. The designer judges product usefulness in terms of capabilities and cost. A major portion of his task relates to the process of balancing engines and armament- the more expensive the engine, the greater the pressure placed on the capabilities to be achieved by the engine and armament together.
The submarine designer’s task may be illustrated by considering the three following engine packages:
Remember that every nuclear submarine carries a diesel and battery as backup power source.
Of the three options, package A is least costly. The designer, beginning with a battery, realizes that the resulting product will have limited mobility and operating endurance. The product, therefore, may be both specialized and expendable. Combining a battery with a single warhead, the designer may define a mine or a limited range, quiet torpedo.
Package B is the medium cost option. Since the diesel engine may be used to recharge the battery, the resulting product, a submarine, can emphasize reusability. In this case, the armament may be increased to permit multiple attacks, thereby balancing product capabilities against investment cost. The designer, when working with the battery/diesel package, need not be driven to multi-role design in order to balance capabilities and cost.
Engine package C is the most powerful and the most expensive option. The designer has found a natural application of package C in the fleet ballistic submarine (SSBN). The armament of strategic ballistic missiles could be rationally expanded to balance the capabilities and cost of the engines. The SSBN is the least expendable, most heavily armed ship ever designed.
In some non-strategic missions, there is a practical limit to the armaments which may usefully be carried on a single submarine. This is particularly true for a submarine which specializes in anti-submarine warfare. In this case, the submarine attack capabilities are limited by its ability to detect, classify, and localize submarine targets. For a given state-of-the-art, there exists an effective upper limit to the sensor and weapon package which may be supported.Consequently, submarine designers of ASW specialized submarines, whether using engine package B or C, tended to back off on speed and power in order to bring the engine into balance with the armament. The SSK and SSKN, TULLIBEE, are examples of such specialists.
Greater speed and power is more easily justified within the context of a general purpose submarine. When the ship and shore attack roles are added to that of anti-submarine warfare, the ceiling on useful armament loads is removed. The submarine designer may select armament levels including anti-ship and land attack missiles which can balance any engine package. The general purpose attack submarine will tend to become larger and more powerful as one generation succeeds another.
This survey of the submarine design factors recaptures the submarine dilemma: The submarine, through advancing engine technology, has evolved from a David to a Goliath- are we to abandon all interest in Davids to defeat Soviet Goliaths? The answer to that question will lie in the decisions we make about new engine research and development. Our American enthusiasm for speed and power should not cause us to exclude the development of more modest engine packages; packages which may be useful in future naval Davids.
Summary and Conclusions- The revolution which resulted from the introduction of nuclear propulsion in attack submarines may have effects on U.s. naval power that are not commonly recognized or discussed. These effects include the following:
Design- in our drive to justify higher submarine speed, the designer is forced to balance the increases in engine investment against larger, more capable armaments. This pattern will commit us to a numerically inferior force of powerful, multi-role submarines.
Tactics- The submarine established its niche in naval warfare as an inexpensive means of defeating powerful surface ships. With nuclear engines, the submarine itself has become both powerful and expensive. It has vacated its original niche.
Strategy- Strategic assumptions are tailored to accept the attributes of the new, powerful attack submarine; the strategic assumptions which accomodated the pre-nuclear submarine have bee abandoned. In other words, Goliath has superceded David.
Americans are quite properly advocates of nuclear engines in submarines. The submarines of World War II had great leverage in terms of counter force requirements. The powerful nuclear submarine will increase this pressure. Unfortunately, the concept of submarine leverage is a two-way street. If we concede to our opponents a continuing numerical advantage of three to one in submarines, it could prove that it is we Americans who have a leverage problem. Should this be the case, there remains a niche for an affordable, dedicated (not multi-role) means of stopping powerful Soviet submarines. Submarines are most suited to this task. How well they accomplish this task requires equal consideration of a choice of weapons and a choice of engines. Above all, we must preserve the opportunity to choose.