THE ADVENT OF TRUE SUBMARINES
During World War II the submarine’s principal roles were commerce destruction and hunting enemy surface warships. The antisubmarine forces of the United States and the British Commonwealth comprehensively defeated the submarine campaigns of both Germany and Japan against both merchant shipping and naval forces with a combination of superior tactics and technologies. Nevertheless, it was clear that new submarine technologies could potentially negate this superiority. In particular, the advent of the German Type XXI submarines, the elektroboote, was especially worrying. They combined high underwater speed, rapid manoeuvrability, substantial submerged endurance, deep diving, and long range without needing to surface. These attributes resulted from the installation of greatly enlarged batteries and more powerful electric motors in a shorter, deeper, stronger, streamlined hull, and the use of snorkels to operate the main diesel engines underwater. While the Type XXI did not represent a mature technology, its potential was clear, and its design features powerfully influenced submarine development after World War II, especially in the United States and the Soviet Union.
The advent of the Cold War forced a thorough reappraisal of the role of submarines in the fleets of the United States and its allies. Maintenance of maritime commerce, the movement of troops, munitions, and equipment across the oceans to Europe and the Far East, and the forward deployment of powerful naval surface forces, centred mainly on aircraft carriers, all were vital components of the West’s strategy for containing the Soviet Union and for conducting operations should a war break out. The deployment of mature submarines with the capabilities of the elektroboote potentially could jeopardize the West’s ability to undertake all three. One part of the solution to countering fast, true submarines was the deployment of fast, effective surface and aerial antisubmarine assets, but that addressed only containing and defeating submarines once they had reached the open ocean. The other, and potentially more efficient, option was to deploy the West’s own submarines to hunt and kill enemy submarines before they could reach the oceans, and that therefore became one of the submarine’s primary missions.
The Soviet Union also had to re-evaluate the purpose of its submarine force. One primary role quickly emerged: defending the nation’s coast and ports against attack through offensive operations against the West’s surface maritime assets—especially carrier forces and oceanic lines of communications—and defensive operations against submarines attempting to prevent the egress of Soviet boats.
Both sides in the Cold War quickly came to view enemy submarines as the primary target of their own boats, especially as both began deploying submarines as platforms for strategic missile attack against the other’s homeland; in addition, the Soviet Union also placed great emphasis on offensive missions against the West’s carrier groups.
At the beginning of the Cold War, all operational submarines used diesel-electric drive. This required submarines either to surface frequently to recharge their batteries, or that they be equipped with a snorkel breathing device. The initial primary focus of submarine development, especially in the United States and the Soviet Union, was the integration of experience from analysing and operating the German elektroboote into their fleets.
The U.S. Navy took a three-track approach to this task. The first, longer-term approach was to explore new propulsion technologies that would free submarines from the limitations of diesel-electric drive; this led to the introduction of nuclear-powered boats. The second was to develop new designs that embodied the principles of the Type XXI boats within the framework of U.S. requirements. New long-range submarines of the Tang class and short-range hunter-killer types emerged, but their numbers fell far short of the fleet’s requirements. To a great extent, however, budgetary constraints forced the U.S. Navy to pursue most vigorously the least attractive option: modifying, through the GUPPY program, as much as possible of the large existing fleet of new but obsolete submarines built during World War II for greater speed and underwater endurance. Large numbers of almost new Gato, Balao, and Tench class fleet submarines received more streamlined casings and sails, enlarged batteries, snorkels, and improved sensors to suit them for submerged operation for more extended periods.
The United States also undertook research on improved hull forms for extended high-speed submerged operation, leading to the construction of the experimental Albacore by the Portsmouth Naval Shipyard in 1952–1953.
The Albacore was revolutionary: the hull was a teardrop shape, optimized for underwater operation; there was a single propeller; and the installation of a massive battery permitted very high submerged speed, albeit for only short periods. The new hull form demonstrated great manoeuvrability, and exploiting it led to substantial improvements in subsequent submarine control systems, making them more akin to flying an aircraft than operating a boat. The Albacore also was subject to many modifications, especially to the stern, which eventually received an X-tail that increased overall length to 210’ 60”; several different types of propeller and rudder arrangements were tried, and the boat also tested new configurations for sonar installations.
The new shape demonstrated by the Albacore quickly found its way into operational submarine service, both for diesel boats and for nuclear-powered submarines, in the United States and elsewhere. Its wide adoption marked the completion of the process of transformation from submersible surface craft to full submarines. In the United States it found its principal application in the development of nuclear-powered boats; only the three diesel-electric submarines of the Barbel class took advantage of its characteristics.
The Soviet Union followed a somewhat different course in developing its new submarine fleet. In many ways it was far more conservative, from a design standpoint. Essentially, it chose to integrate the principles of the elektroboote into the design of updated iterations of the existing three basic types: coastal, medium-range, and long-range boats. Unlike the United States, the Soviet Union put these new designs into mass production, building 32 coastal Project 615 ( NATO-designated Quebec) boats, more than 200 Project 613 ( NATO-designated Whiskey) medium submarines, and 22 of the long-range Project 611 (NATO-designated Zulu) type.
The Soviet Union also explored new submarine propulsion technologies and adopted nuclear power some four years after the United States. Unlike the United States, however, the Soviet Union did not end production of conventionally powered submarines. Large numbers of new diesel-electric Project 633 (NATO-designated Romeo) and Project 641 (NATO-designated Foxtrot) boats, again of relatively conservative design, were built to supplement the earlier Project 613 and Project 611 types. Both types nevertheless were successfully exported to countries within the Soviet sphere of influence and laid the basis for conventional submarine production in both China and North Korea.
The Soviets in addition saw a role for conventionally powered submarines in the anti-carrier mission, manifested in the production of the Project 651 (NATO-designated Juliett) and Project 641BUKI ( NATO-designated Tango) boats in the 1960s and 1970s, whose principal weapons were anti-ship cruise missiles. The earlier type saw operational characteristics on the surface take pride of place, inasmuch as it had to surface to launch its missiles and needed stability for that purpose. The missiles of the later boats were launched while it was submerged, and consequently a modified form of the earlier Project 641 attack submarine hull was found satisfactory.
The Royal Navy took a somewhat different approach to new submarine production immediately after World War II. Alone among Allied navies, it had direct experience in creating submarines with high underwater speed during the war, having converted several S class boats into high-speed targets for antisubmarine forces. It used that experience, plus additional information derived from study of the German elektroboote, to generate its own conversion program to build up a force of fast boats from recently completed T and A class submarines, while working to make more radical propulsion technologies reach production maturity.
The Admiralty looked into nuclear propulsion but decided to exploit the German Walther close-cycle turbine system for its non–air breathing submarines, because it seemed less expensive and closer to being ready for service. Unfortunately, British experts were under the impression that German technicians who had tested this system in a small number of experimental platforms were much closer to solving all of its problems than was really the case. The Royal Navy built two special experimental boats, the Explorer and the Excalibur, as platforms to bring the Walther system to production status; in the meantime, they built new conventional submarines that, while very reliable and generally quite effective, did not represent much of an advance on the conversions of wartime boats or the German elektroboote. The failure of the work in developing a mature Walther system left the Royal Navy no alternative but to turn to the United States for nuclear power technology when the time came for it to build its own submarines that would be free from the limitations of diesel-electric propulsion.
In the early 1980s the Soviet Fleet introduced a new conventionally powered attack submarine, in large part because it was easier to create a quiet diesel-electric boat. The Project 877 (NATO-designated Kilo) type was specifically designed for antisubmarine warfare and combined a teardrop hull form with a powerful sensor suite and stringent measures to reduce acoustic and magnetic signatures. These relatively large, conventionally powered boats proved very successful. They were among the quietest boats of their era and also became a considerable export success, both in their original form and as the upgraded Project 636 (also designated Kilo by NATO).
For most other nations the leap to nuclear power for submarines was out of the question, because of the absence of the necessary industrial and scientific infrastructure, its great expense, and, in some instances, political obstacles. Instead, they exploited the elektroboote technologies to produce a new first generation of Western, conventionally powered fast submarines.
The second generation of post-war diesel-electric boats represented a substantial advance on the earlier types. Three elements combined to create these new boats: great strides in battery technology, new hull forms inspired by the Albacore design, and advances in reducing acoustic and magnetic signatures. New battery designs not only generated more power for the same space and weight but also recharged much faster, enabling submarines to operate fully submerged for longer periods and use their snorkel on a much more limited scale. New hull forms, and advances in metallurgy, endowed these boats with higher speed, greater manoeuvrability, and deeper diving capabilities.
Reduced magnetism came from using nonmagnetic, high-tensile steel or active demagnetizing. The biggest asset, however, that these later-generation diesel-electric boats possessed was quietness and, therefore, stealth. Rafted machinery, slow-speed motors, advanced propeller designs, sophisticated streamlining, and anechoic hull coatings all dramatically reduced their acoustic signatures. When combined with their small size, especially relative to nuclear-powered submarines, and thus an ability to operate in confined waters, this stealth made later diesel-electric boats very difficult targets for aerial, surface, and subsurface antisubmarine forces.
Several producers of advanced conventional boats were able to turn these assets into lucrative export production. Beginning in the 1970s, France, Sweden, and above all Germany began to dominate the market for advanced conventionally powered submarines worldwide. The most successful by far is the family of German Type 209 submarines, of which almost 60 have been delivered or are on order for 15 nations. Moreover, since many of these export boats were ordered by fleets without solid experience of modern submarine operations, lucrative training and support contracts often accompany the orders for the hardware, and contribute to the spread of a remarkably uniform ethos of operation.
Ambitious German plans to build Walter-designed ocean-going submarines, such as the 1,600-ton Type XVIII, were thwarted by the unsuccessful course of the war, The Type XVIII was modified into the highly successful Type XXI “Elektroboots” [“electro-boat”] in which larger batteries provided a submerged speed of 17 knots, which could be maintained for 90 minutes. That innovation, and the adoption of the snorkel, yielded a potent combination that strongly influenced the post-war design of conventionally-powered submarines on both sides of the Iron Curtain. Type XXI U-boats were the first submarines designed to operate entirely submerged, rather than as surface ships that could submerge as a temporary, awkward mode of operation.
Following the Second World War the German U-Boat technology provided the Soviet Navy with technological improvements. The German Type XXI submarine was capable of 18 kts submerged, could dive to nearly 1,000 feet and included a schnorchel (snorkel) mast to allow for diesel operations and battery charging while submerged.
During the five years following the end of World War II, Soviet exploitation of the Type XXI lagged significantly behind American fears. US intelligence initially foresaw in 1946 a force of 300 Soviet Type XXI equivalents by 1950. But it was not until 1949 that the first post-war Soviet submarine designs — the Whiskey and the Zulu — put to sea. The Zulu was a true Type XXI, equipped with a snorkel, capable of 16 knots submerged, and possessing the size, habitability, and range necessary for long range, blue water interdiction operations. But only 21 Zulus were commissioned between 1949 and 1958.
During the 1950s, including efforts to convert Zulus into ballistic missile submarines (SSBs). The world’s first SLBM submarines were the Soviet Zulu-class, diesel-electric-propelled vessels armed with two SS-N-4 missiles. These undersea craft, converted to the SLBM role in 1958-1959, were followed by the new-construction Hotel (nuclear) and Golf (diesel) classes, each of which carried three missiles.
The Soviet Navy never lost faith in the SSK, and continued to build them in parallel with SSNs. When the huge Project 613 ‘Whiskey’ programme came to an end in 1958 no fewer than 215 had been built, and 21 more were assembled in Chinese yards. The improved Project 633 ‘Romeo’ type never achieved the same popularity – 20 being built in 1956-64 for the Soviet Navy and others built for export. The Project 611 ‘Zulu’ type, a 1930.5-tonne (1900-ton) ocean-going boat, ran to 30 units, but large-scale production returned with the 62 Project 641 ‘Foxtrots’ built from the early 1960s to 1971. The 19 Project 641 BUKI ‘Som’ class (’Tango’) were specialised antisubmarine boats built from ‘Foxtrot’ components.
Very much like the battery capability given to the Tang class by the Americans to achieve the kind of speed displayed by the German Type XXI’s at the end of World War II, this boat had an increased number of batteries that provided the capability of remaining submerged for 300 hours at very slow speed. The Romeo also had hovering capability. In many ways, it was the ideal pre-nuclear surveillance boat. These vessels came off the ways in the late 1950s, roughly the same time as the advent of the first Soviet Nuclear boats, the November class.
Cold War Submarine Operations by the West
Three circumstances radically changed the paradigm of Western submarine operators immediately after World War II: the Allies’ overwhelming victory in that conflict, the transformation of the Soviet Union from an ally into the West’s preeminent opponent, and the advent of true submarines—epitomized by the German Type XXI boats, whose technology was readily accessible to all the erstwhile allies. Countering the potential major threat fast submarines could present to transatlantic and transpacific lines of communications and to the free operation of Western surface task forces permeated naval planning. Consequently, antisubmarine warfare, both defensive and offensive, became the central focus of Western submarine operations.
The limitations of existing boats, even after major modifications such as the GUPPY program in the U.S. Navy, and the constraints of current propulsion technologies at first entailed concentration on interception. Submarines were deployed forward, ideally in close proximity to Soviet naval bases or, if that was impractical, at “choke points,” relatively tightly defined passages through which Soviet boats would have to travel to reach their targets. Early hunter-killer tactics relied on slow, stealthy boats using passive sonar and fire-control equipment, but actual operations quickly demonstrated the limited effectiveness of both the boats and their electronics.
The advent of nuclear-powered boats quickly changed the antisubmarine warfare situation for Western submarines forces from the 1960s. Their greater size provided space for very powerful sonar o u t fits whose capabilities finally came close to fulfilling the needs of stealthy hunter-killer operations. Their vastly enhanced submerged endurance made prolonged ambush deployments off Soviet bases or at choke points a realistic option. Powerful sonar, speed, and endurance also opened up the possibility of maintaining continuous submerged surveillance of Soviet submarines; an urgent requirement in the Cold War situation once the Soviet Union began deploying strategic missiles aboard dedicated submarine platforms. Furthermore, the submerged speed and endurance of nuclear boats at last made feasible the long-running concept of fleet submarines. They, however, did not take on the role of ambushers of enemy surface forces (the original fleet submarine concept) but rather operated as effective wide-ranging, stealthy escorts for important fast surface task forces, especially those centred on carriers which had become the principal targets of Soviet submarines. The operations of British nuclear boats as distant escorts for the task force operating against the Falklands/Malvinas in 1982 vividly illustrated this role; the sinking of the Argentinian cruiser General Belgrano on 2 May by HMS Conqueror and the subsequent self-blockade of Argentina’s carrier Veinticinco de Mayo in port thereafter clearly demonstrated how effectively submarines could perform task force escort missions.
Two developments further expanded the mission portfolio of Western submarines: the use of submarine-launched cruise missiles and the growth of the Soviet surface fleet. The addition of cruise-missile launch capability to attack submarines enabled them to perform land attack missions with great precision against narrowly defined targets. During the 1990s submarine-launched punitive Tomahawk cruise missile strikes against facilities of specific importance became the means of choice whereby the United States attempted to reinforce its foreign policy decisions and retaliate against regimes and organizations for attacks on U.S. citizens and assets. For example, on 20 August 1998 the United States launched Tomahawk missiles against six terrorist bases in Afghanistan and a factory in Sudan suspected of producing nerve gas in retaliation for the bombings of U.S. embassies in Kenya and Tanzania on 7 August. The commissioning of aircraft carriers into the Soviet Fleet also promptly revitalized the submarine mission of surface warship attack, so that Western nuclear boats took on the role of shadowing Soviet carrier forces that long had been an important function of Soviet submarines.
Cold War Submarine Operations by the Soviet Bloc
At the end of World War II the Soviet Union had the largest submarine force in the world, although it was far from being the most effective either in the quality of its equipment or its operators. The onset of tensions with its erstwhile allies in Western Europe and North America that led to the Cold War made containing the threat of the West’s overwhelming naval preponderance, and especially its carrier forces, a major Soviet military goal. Consequently, using as a basis the captured German elektroboote technology, the Soviet Union rapidly built up a very large force of modern submarines whose primary missions were intercepting and shadowing Western carrier forces and, should a conflict occur, attacking the transatlantic shipping bridge that carried reinforcements and supplies from North America to Europe.
A second mission quickly developed: countering Western submarines that had adopted antisubmarine warfare as their primary task. A dangerous cat-and-mouse game ensued that persisted throughout the Cold War between Soviet and Western submariners, primarily in the waters of the Arctic, North Atlantic, and North-western Pacific oceans, and the Mediterranean Sea. The boats, their equipment, their weapons, and their operators became ever more sophisticated but the objective remained the same: to secretly intercept an opponent and maintain stealthy contact thereafter.
The deployment of Western ballistic missile submarines quickly led the Soviet Navy to react in the same way as Western forces by deploying its attack submarines for operations to locate and shadow the missile boats from their departure from port throughout their missions. Stealth, endurance, and sophisticated sonar and fire control were crucial to the success of such operations, which persisted throughout the Cold War and beyond to the present.
Anti-carrier operations received a substantial boost in effectiveness with the advent of fast nuclear boats armed with long-range anti-shipping missiles. This development closely coincided with the deployment of Soviet strategic missile submarines, whose survival in the open waters of the Atlantic and Pacific depended heavily on the ability of Soviet attack boats to neutralize Western carriers and submarines. This became even more important with the advent of long-range ballistic missiles capable of targeting North America without their launch platforms having to leave the relative safety of the Arctic Ocean. The Soviet Navy developed the concept of “bastion defence” in which its attack submarines and strong surface antisubmarine forces would neutralize Western efforts to penetrate this zone of safety with their boats while the Soviet anti-carrier force prevented U.S. carrier task forces from supporting penetration operations or initiating their own attacks on the strategic missile submarines.
Throughout the Cold War attack submarines operated by all the protagonists played a vital role. They were in the forefront of both defensive and offensive operations, operating right off their opponent’s bases, trailing both surface and submerged opposition assets, and protecting their own forces from interception and possible attack.