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By Rear Admiral James Fitzgerald, U.S. Navy, and John Benedict
. . . And the Navy needs to brace for it. These days, the threat lies in the hands of the Third World. Thanks in large part to superpower exports, such as the British Tigerfish torpedo that broke the back of this target destroyer, Third World navies have become a force to reckon with. Today’s ASW efforts should reflect this new reality.
I
For more than 30 years, U.S. Navy anti-submarine warfare (ASW) planning has focused nearly exclusively on the Soviet submarine force. The large order-of-battle and high priority that the Soviets assigned to their submarines justified the extensive ASW intelligence activity, programs, tactics, and training that the United States considered necessary to address this potential threat. In light of such a large ASW order, it was easy to neglect other potential threats and warfighting scenarios. We have generally rationalized that any other threat was a “lesser-included case” of a general war.
Over the last 15-20 years a disturbing trend has magnified the significance of these cases. We have seen a steady increase in the availability of .high-technology military platforms and weapon systems to developing countries, often referred to as the “Third World.” During the five- year period from 1983 to 1987, developing countries accepted nearly $190 billion (in real dollars) worth of military arms of all types. The Soviet Union provided more than 40% of these arms, a number higher than those provided by the United States and France and all of the NATO Allies combined.
Even with military budget constraints imposed by both the West and the Soviet Union, arms proliferation will likely continue at high levels or even increase. The Soviets need the hard currency provided by military sales to buy Western technology and strengthen their economy. Western manufacturers will have fewer restrictions imposed on them based on this technology transfer. Impressive indigenous arms industries are emerging in the Third World that will have even fewer constraints imposed with respect to arms deals. And perhaps most significant, various regional animosities show little sign of abating, which means that more countries will be searching for high- technology weapons in the future.
The apparent change in Soviet intentions and reduced ability to mount a central front offensive in Europe are good news. Some reductions in military spending will be possible, but perhaps more important, the Navy has an opportunity to take a more balanced approach in establishing its warfighting requirements. Realistic threat assessments are being made for various Third World contingencies and limited objective conflicts. What is evident is that warfighting requirements in Third World contingencies are not simply a subset of the requirements that have emerged to counter the Soviet threat. Some adjustments will be needed to ensure the continued effective employment of naval forces in Third World regions. Unlike the NATO/Warsaw Pact conflict, Third World contingencies are likely to occur as long as we have allies to defend and national interests to protect.
Submarine Proliferation
Apart from the U.S. and Soviet navies, 41 other countries operate more than 400 submarines. Nearly half operate under the flags of 19 Third World countries. In addition to numbers, access to modern diesel submarines is at an all-time high. The Soviet Union began exporting its most modem diesel submarine, the Kilo, during the
1980s. In a three-year period the Soviets exported three of every four new Kilos. India has received a total of seven Kilos, and Algeria has received two. Libya and Syria may soon augment their submarine forces with modern Kilos as well. The Kilo exports are very similar to those being retained by the Soviet Navy. Thus, they are much more capable than their previous Romeo, Whiskey, and Foxtrot exports.
In the Free World, the West German consortium HDW/ IKL/FS has been the most successful in the diesel submarine export market. They delivered 15 units to 8 nations during the last decade. Their Type 209 series has been very popular in Third World navies, including recent variations for India (“Type 1500”) and Brazil (209-1400). Indonesia and five other Latin American countries also have 209s. Argentina has recently acquired West German TR 1700s that represent a design departure from the Type 209 series. South Korea has placed orders for six Type 209s, the last batch of 3 reportedly selling for a unit price of $165 million. Israel has two Type 209s on order with West Germany. Fortunately, the six Type 209s ordered by the Shah of Iran were canceled after he was dethroned. Recent Persian Gulf operations would have been much more difficult if Iran had deployed several modern diesel submarines in the region.
The United Kingdom has penetrated the Third World diesel submarine market in deals with Brazil (Oberon), Israel (Type 540), and Egypt (scheduled to receive two Oberon/Porpoise soon and a possible six more in the future). France has exported submarines to Pakistan (Agosta, Daphne) and South Africa (Daphne). The Netherlands has provided submarines to Taiwan (Zwaardvis derivatives), and Sweden is also trying to export submarines to the Third World. Malaysia, Thailand, Iraq, Saudi Arabia, and Nigeria are considering orders of diesel submarines for their navies. Currently, approximately 45 submarines of Western origin are operating in the Third World, with this number potentially doubling in the next 10—15 years because of increased demand and increased competition among producers.
Another avenue for Third World countries to attain modem diesel submarines is to produce them indigenously. Both China and North Korea have already accomplished this with their Romeo programs, China with the help of the Soviet Union and North Korea with the help of China. It is not clear what the future submarine order-of- battle for either of these countries will be. At present North Korea has about two dozen diesel submarines, and China has 90-100, many of which may not be operational. It is doubtful that China can replace this submarine force on a one-for-one basis.
India, with the help of West Germany, successfully launched in 1989 its first indigenously produced subma- r'ne a Type 1500. The Germans have also been helping Brazil and Argentina to develop indigenous submarine production capability, although the Argentine effort is on hold. Taiwan and South Africa may have similar ambitions. South Korea already has built a small coastal submarine and with West German help will soon be producing its own Type 209 submarines.
Third World ASW Implications
objective conflicts, it is evident
that a number of ASW capabilities are required.
- Torpedo defenses—diverse and robust defenses, nearly impregnable.
- Shallow-water ASW—special sensors and weapons, adaptation of existing deep water systems to assure graceful degradation.
- Tactical oceanographic support—due to unfamiliar or highly variable, marginal seas.
- Deployable regional surveillance—to compensate for lack of coverage by fixed surveillance systems and possible employment constraints for mobile systems.
- Nonacoustic ASW—to exploit submarine operating constraints in confined and shallow sea regions.
- Command, control, and communication (C3I)/coherent tactical picture development—to allow optimum use of limited resources and to avoid collateral battle damage.
- Third World intelligence— technical and operational intelligence on Third World navies, comparable to that gathered for Warsaw Pact.
- Surveillance and intelligence support to on-scene commander—near real-time support, including national assets focused on Third World contingency region.
- Tactical deception to reduce submarine encounters—use deception to exploit lack of adversary operational competence, force frequent periscope checks.
- Organic air ASW capabilities—to offset lack of available basing and forces, allow fewer combatants to conduct adequately effective ASW.
- Robust at-sea resupply—to offset high ASW ordnance/ sonobuoy expenditures, even without forward basing.
—Fitzgerald and Benedict
It is not clear whether the number of Third World submarines worldwide will increase this decade, particularly in view of China’s uncertain submarine force. However, the quality of submarines will continue to increase dramatically in accordance with Soviet, West German, other Free World, and Third World submarine design developments. The days of old Soviet Whiskeys and Ex-U.S. Guppy- class submarines will soon be gone in this era of high technology transfer.
Improved Quieting and Submerged Endurance
Diesels operating submerged on battery at low speeds (non-cavitating) have always been difficult passive acoustic targets. Limited exploitable narrowband signatures and very low broadband radiated noise have often confounded ASW forces attempting to locate them. The best opportunities were during intermittent snorkel operations. However, this may be changing radically for two reasons. One, modern diesel submarines such as Kilos and Type 209 derivatives have significantly quieter snorkel signatures. Two, high-density batteries today and air independent propulsion (AIP) schemes in the near future will greatly reduce the need for frequent snorkeling.
Four AIP concepts are actively being pursued by the West and perhaps by the Soviets as well: closed-cycle diesel engines, fuel cells, Stirling engines, and low-power nuclear reactors. In each case, the AIP technology is to be used in a hybrid configuration with the diesel engine in order to provide a secondary power source of 100-400 kilowatts. This secondary power source would normally be used to run the generators needed to recharge the ship batteries without any need to go to the surface for air. Closed-cycle diesel engines and Stirling engines typically rely on stored liquid oxygen to achieve air independence. Fuel cell systems rely on stored reactants such as oxygen and hydrogen to produce electricity directly from chemical reactions without any combustion.
The main utility of the AIP techniques is to increase the submerged endurance of diesel submarines patrolling at low speeds (4-6 knots). High-speed operations exceed the power output of these systems. However, for low-speed operations, the battery can be kept at full charge indefinitely with the “nuclear battery charger” and for up to two to four weeks with the nonnuclear AIP concepts that are limited by such things as stored oxygen constraints.
These AIP techniques also have applications for minisubs. The Italian firm Maritalia is developing a 150-ton
Air Independent Propulsion
Four independent paths may achieve greater “air independence” for diesel electric submarines. All four technological approaches provide secondary power sources for recharging the main ship batteries in order to
tery designs. Twenty-five years ago, nonnuclear submarines were typically required to “snorkel” on diesel generators one or more times each day. This was necessary to extract the air required to recharge the ship bat
Comparison of Air Independent Propulsion (AIP) Technologies
increase submerged endurance capabilities for diesel submarines, heretofore limited by evolutionary improvements in bat
teries and keep them in a “topped off” state for maximum flexibility.
Battery advancements now
allow modern diesel submarines to go as long as 4-10 days without snorkeling, depending on battery capacities, battery discharge rates, submarine patrol speeds, and just how low the submarine commander is willing to let the battery discharge. Air independent propulsion (AIP) technologies are intended to provide 100-400 kilowatts of power to allow slow-speed submerged operations (4-6 knots) for two weeks or more and still keep the batteries at full charge. The air independence is provided either by stored oxygen, by stored reactants, or by a low-power nuclear battery charger.
Closed-Cycle Diesel Engines. These attempt to recycle exhaust back to the engine intake, where it is mixed with oxygen, fuel, and possibly a working gas in just the right amounts to maintain a continuous, efficient combustion process. Two very different closed-cycle systems for submarines are currently being pursued by Western manufacturers. The first is the “toroidal” system that has been developed by the Italian firm Maritalia for
submarine that utilizes a closed-cycle diesel system to travel at least 1,600 nautical miles at eight knots or less speed. This translates to at least eight days of submerged endurance and is achieved by a clever “toroidal” pressure hull configuration that stores oxygen and exhaust gas. The mini-sub can be designed with either two heavyweight torpedo tubes, four lightweight torpedo tubes, or two swimmer/mine/combat delivery vehicles in a lock-in, lock-out chamber. In a confined sea region, this would represent a serious threat to warships, particularly if on patrol or at anchor.
The final advanced submarine propulsion concept that is coming to the Third World is high-power nuclear propulsion. The French Rubis submarine is the smallest nuclear attack submarine (SSN) in the world (weighing less than 3,000 tons) and is available for export. Its cost is more than twice that of a Type 209 diesel, but it provides unlimited submerged endurance. The core life of its reactor is reported to be approximately 25 years, which is an attractive feature for Third World navies. The Soviets also leased a Charlie nuclear-powered guided missile submarine to India in January 1989. Will they be selling, renting or leasing Victor Ills in a few years? In addition, several Third World countries are pursuing indigenous nuclear submarine production capability. India has had an indigenous SSN development program since 1974. Brazil has a similar program, and Argentina once had one, but it is on hold. By around 2010, a breakthrough in indigenous nuclear submarine capability is entirely possible.
Submarine Weapons Proliferation
All the diesel submarines previously identified have four to eight 53-centimeter (cm.) torpedo tubes and would typically carry 14-18 heavyweight (HW) torpedoes. Soviet exported submarines are equipped with 53 cm. torpe-
a 30-ton submersible used commercially by the oil industry.
This system is referred to as the '3GST9” and reflects the unique gas storage toroidal system contained in three-inch Pipes welded together to form a 'urge section of the pressure hull f°r this nine-meter-long vehicle. The three-inch pipes are used to store both liquid oxygen and engine exhaust gas, including carbon dioxide, which is used as a working gas for this closed cycle concept. Oxygen, carbon dioxide, and fuel are combined at the engine intake. Excess exhaust products are compressed and stored in the toroidal system. There is no need for any overboard discharge. Currently under development by Maritalia is a 150-ton mini-sub that is 27 meters long and has even larger diameter pipe sections for gas storage that will allow about a Week of submerged endurance. Whether this type of design will continue to scale up with larger submarines and produce even greater capacity for submerged endurance (two or three weeks) js uncertain, but this application ts being pursued by the Italian company Fincantieri, which owns Maritalia.
An alternative closed cycle concept for submarines is being explored by the firm RDM of
Holland based on the “Argo” system designed by the British firm, Cosworth Engineering.
The Dutch “Spectre” system, as it is now termed, relies on a unique exhaust scrubber and water management/overboard discharge technique. This system dissolves carbon dioxide into sea water and maintains adequate pressure for overboard discharge down to depths of 300 meters without a significant increase in system power requirements. This represents a technical breakthrough, because previous closed-cycle systems attempting overboard discharge at depth have proved very inefficient because of increased power demands. Stored liquid oxygen is the key to achieving air independence for this system. Oxygen, an inert working gas (argon, to achieve proper specific heat), recycled exhaust, and fuel are mixed in correct proportions to maintain combustion. The submerged endurance capability achieved will be largely limited by stored liquid oxygen capacity and the overall efficiency of the closed cycle system.
Stirling Engines. The Stirling engine is a reciprocating, external combustion engine. The Swedish Navy is examining such a system for their next-generation diesel submarine. A 1,000- ton Nacken-class submarine is serving as an at-sea test vehicle. An eight-meter hull extension was required to accommodate two Stirling generators, additional fuel, liquid oxygen tanks, and a control system. The Stirling engine has thermodynamically connected pistons that transmit mechanical work to a drive shaft and also move a working gas (helium) through a regenerator/cooler (heat sink) between hot and cold sides of the engine. Expanding hot gases will force a particular piston down, with the hot surface of one piston being coordinated with the cold surface of another piston. Unlike internal combustion engines, Stirling engines feature continuous burning in an external combustion chamber, which is kept in overpressure to facilitate overboard discharge of exhaust gases down to 300- meter depths. Stirling engines are considered quiet in operation because of their lack of explosions and moving parts in the combustion chamber, low system vibration, and low engine revolutions per minute. Other external combustion engines include Brayton and Rankin cycle variants that rely on closed-cycle turbines and are smaller but less efficient than Stirling engines.
does with thermal propulsion that have relatively long endurance and high-speed features compared to torpedoes with electric propulsion. They also have large 400-kilogram (KG) warheads. Western export torpedoes such as West German (SUT/SST-4), United Kingdom (Tigerfish), French (F-17P) and Italian (A 184) designs have wire guidance and advanced acoustic homing capabilities. They generally have quiet electric propulsion and moderatesized 250 KG warheads.
Both Western and Soviet HW torpedoes are potentially lethal against surface combatants. The U.S. frigate Samuel B. Roberts (FFG-58) was nearly cut in half by a contact hit from a 100-125 KG World War I design mine in the Persian Gulf. During the Falklands Conflict the 13,000-14,000-ton Argentine cruiser Belgrano was sunk by two 340 KG warhead MK 8 torpedoes fired by the British SSN, HMS Conqueror. These straight-running torpedoes, based on designs more than 50 years old, killed 368 Argentine sailors. This was more casualties than the British suffered during the entire war, both on land and at sea. Neither the Roberts nor Belgrano was hit by a modern homing torpedo with influence fuzing designed to achieve an optimal underbottom hit.
In addition to torpedoes or mines, several antiship cruise missiles are capable of being launched from 53 cm. torpedo tubes. The United States has exported submerged- launch Harpoons to several Third World countries including Israel, Pakistan, and Egypt (due. to receive in 1993). France may follow suit with the SM39, the submarine- launched version of Exocet. The West Germans can adapt the 53 cm. tubes for their Type 209 variants to fire either Harpoon or Exocet.
Threat to Western Power Projection Forces
The German U-boat campaigns in the two world wars
Reducing the size/weight/ complexity/cost of Stirling engines are current goals as is assuring high system reliability in a marine application. Potentially, this system could provide for two weeks or more of submerged endurance at low submarine operating speeds.
Fuel Cells. The West German Navy is attempting to achieve air independence for its future submarines by using fuel cell technology. A 450-ton Type 205 submarine with a several-meter hull extension has been used to demonstrate this technology.
Fuel cells have the highest potential efficiency (50-70%) of any of the nonnuclear AIP concepts being explored. This overall efficiency is possible, because there is no heat transfer or combustion taking place. Fuel cells are designed to convert chemical reactions directly into electrical energy. In the German case, the chemical reactants are liquid oxygen and hydrogen stored as a metal hydride. In other words, the hydrogen bonds to the metal and is driven off by waste heat produced from the reaction, which is a safer method than storing the hydrogen as a gas under pressure or in liquid form. Separate electrodes bring each of the reactants into contact with an electrolyte solution of potassium hydroxide that is porous to the reactants, thus allowing electron transfer. Fuel cells are purported to have five times the net energy density of a lead-acid battery. In the future, if technical difficulties can be overcome, up to about one month of submerged operation may be achievable for fuel cell-equipped diesel submarines. This could be possible with relatively “silent operation,” because fuel cells rely on no rotating machinery to produce their electricity.
Low-Power Nuclear Reactors. A “nuclear battery charger” could allow unlimited submerged endurance at low submarine speeds consistent with the low power output of the reactor. Canada’s ECS group is currently attempting to develop just such an autonomous marine power source (AMPS). They are adapting a 1960s “Slow Poke” university reactor design that has previously been licensed for unattended operation because of its “fail safe” automatic shutdown features. This small reactor is non-pressurized, non-boiling (95°C), light-water cooled, and employs low-enriched uranium fuel (<20%). The heat produced by the reactor is transferred to a secondary loop in which liquid freon is vaporized to spin a turbine generator. To accommodate this type of marine reactor and associated equipment could require up to a 10-meter plug on some submarine designs. The first application of AMPS technology is scheduled for the French SAGA-I 545-ton commercial submersible, perhaps as early as 1995, when it will be renamed SAGA-N. Currently, the AMPS technology has uncertain government backing and has generated no military sales.
AIP technologies are being developed by the West and possibly by the Soviets as well. As AIP military hardware is developed for Third World diesel submarines in the future, it could dramatically change the ASW equation for dealing with them. The main uncertainties are which AIP technologies will ultimately prevail in the near term, based on various considerations including ship impact, safety, reliability, performance, and affordability. In the very distant future, as these power sources continue to improve, they may replace the diesel generators on nonnuclear submarines.
—Fitzgerald and Benedict
demonstrated that submarine operations force navies to maintain a large and costly ASW capability. In many Third World regions, although only a few submarines can be brought to bear, it will again require a relatively large ASW force capability to counter them. This is particularly evident against modem submarines and in view of other important factors that may offset smaller numbers of submarines. First, risk to naval forces must be consistent with the benefits of the operation. For example, if the objective is a naval “show of force,” then the price of losing a ship and large number of sailors may be too high. Second, neutralizing even a single diesel submarine could prove difficult in view of its limited acoustic signature and the adverse acoustic environments often associated with Third World regions.
Although Third World submarines often have limited seaward reach against modem naval forces, certain other factors may offset that weakness. First, naval forces may be required to operate in close proximity to hostile shores in order to perform various missions such as naval gunfire support, evacuation of civilians, landing of forces ashore, and asserting right of free passage. Second, these naval forces often occupy restricted operating areas for protracted periods, a fact that greatly simplifies the encounter problem for nonnuclear submarines.
Several characteristics of Third World contingencies may offset the limited training and operational expertise of their submarine crews. First, the Third World adversary has a mobile “home field” advantage in waters with which the naval forces may be unfamiliar. Second, less focused intelligence on Third World navies could make them more unpredictable in terms of tactics and intentions. Third, difficult mles of engagement may prohibit precursor operations and restrict attacks on subsurface contacts to avoid collateral damage.
The Falklands Conflict displayed many of the character-
HOWALDTSWERKE. »
istics that make Third World contingencies and limited conflicts difficult. The Argentine Navy employed only °ne modem submarine, the San Luis, a Type 209 manned by a newly assembled and inexperienced crew. This single diesel submarine was pitted against two British ASW aircraft carriers, 15 frigates and destroyers with additional ASW aircraft, and several British submarines. Despite this aPparent mismatch, the San Luis traveled 800 nautical miles from its base, conducted a six-to-seven-week patrol, and generated three torpedo attacks. Two of these were valid attacks against British warships in which the Argen
Non-superpowers also have dabbled in Third World submarine exports. Here, India’s 1500-type Shishumar (SS- 44) is shown under construction in West Germany at Howaldtswerke.
tines fired a single SST-4 HW torpedo. In both cases the attacks were unsuccessful—fire control computer casualties and torpedo wire breakage occurred several minutes into the runs. A lack of realistic training caused these problems, and could have been corrected easily if they had been identified before the conflict.
In the end, the British were very fortunate not to have lost a warship to torpedo attack. The suspected presence of the San Luis did cause them considerable concern such that, for a time, the British attacked all unresolved contacts with ordnance. More than 200 pieces of ordnance were expended in all, including numerous depth charges and a large number of homing torpedoes, the majority of which exploded amidst a sea full of false contacts.
Detection and destruction of modem submarines—both nuclear and nonnuclear—is the most challenging single task in naval warfare today. There is no cheap solution and no panacea. ASW remains force-intensive, requires advanced technology solutions, is very sensitive to the ocean environment, and is highly reliant on tactics and training. ASW operations against modern nonnuclear submarines with advanced weapons under adverse operating conditions are potentially more demanding than operations against SSNs in the open ocean. Further, in contingency and limited objective operations, no navy may be able politically to afford even a single point failure in ASW.
Rear Admiral Fitzgerald is currently assigned to the Joint Chiefs of Staff as Deputy Director for Current Operations (J-33). He is the Director of the ASW Division (OP-71) in the Naval Warfare Directorate of OPNAV.
Mr. Benedict is a member of the Principal Professional Staff of The Johns Hopkins University Applied Physics Laboratory in the Naval Warfare Analysis Department, specializing in ASW.
Dutch Treat
The Royal Netherlands Navy frigate Van Kinsberger was on patrol in the North Atlantic with the British auxiliary cruiser Circassia in the early days of World War II.
The Dutch captain was keen on camouflage and had chosen the dazzle paint on the sides of the frigate carefully. Not completely satisfied, he gave orders to rig up an extra canvas dummy stack. He then signaled HMS Circassia, three miles away, “How do you like my camouflage?” The Circassia immediately blinked back, Where are you?
V. J. L. Bloom
_Just Bargin’ Along
Back in the 1930s when the battleship force anchored in the Long Beach area, most of the small boats went in to the San Pedro landing. Many complaints were received about the damage done by the wash of the speeding boats. Strict orders were issued to make slow speed in the channel.
One coxswain was put on report for failure to carry out these orders. At Captain’s Mast, the skipper of the flagship asked, “Did you make full speed up the San Pedro channel?”
“No, sir,” replied the coxswain, “but 1 passed a lot of boats that were.”
A. M. Charlton