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Proliferation of Modern Submarines

Significant military technology is being transferred to developing countries of Africa, Asia, Latin America and Oceania – countries often referred to as the “‘Third World”. During the five year period 1983-1987, nearly $190 billion dollars in military arms were transferred to Third World clients by various suppliers. The most recent trend in Third World arms delivered by U.S., Soviet and major Western European suppliers has been down due to the cessation of the Iran-Iraq war in mid-1988 and various debt problems for developing countries. The value of these arms (in constant 1989 dollars) decreased by about 20% during 1986-1989 compared to a similar period from 1982-1985. The number of weapons delivered during these same two periods decreased by a corresponding 30-60% for most major weapon categories (tanks, other armored vehicles, naval surface combatants, combat aircraft, surface to air missiles, etc.), reflecting the increasing unit cost of military hardware. Submarines were the only major weapon category that defied the overall trend. The number of submarines delivered to the Third World actually went up by 30%. This is consistent with other trends such as the more than 20% increase in the combined Third World submarine order-of-battle that occurred from January 1980 to January 1990. Today, twenty Third World countries have approximately 200 submarines, about half the total of more than 400 non-U.S./USSR submarines worldwide.

Nearly 45 Western supplied diesel submarines of relatively modern vintage (less than 20 years old) are operational in Third World navies today. More than half of these were supplied by West Germany to seven South American countries, Indonesia and India. The vast majority are variants of the popular TYPE 209 series produced by the HDW/IKI./FS consortium that offers “cradle to grave” service to their customers. In addition to building the submarines, the Germans also provide support in maintaining, operating and modernizing them. They also will teach Third World clients to build the TYPE 209 for themselves. India has launched its first indigenously produced TYPE 209-1500. Argentina and Brazil are learning indigenous production from the Germans as well. South Korea and Taiwan are also expected to produce TYPE 209s during the 1990s. South Africa and Israel may have similar ambitions for an indigenous submarine production capability.

Orders for more than twenty additional 1YPE 209s have been placed or are being negotiated with countries such as South Korea, Taiwan, Israel, Brazil and India. Other potential Western suppliers include the United Kingdom (OBERON submarines previously to Brazil and Chile, currently to Egypt), France (AGOSTA/DAPHNE submarines previously to Pakistan and South Africa), the Netherlands (ZWAARDVIS derivative previously to Taiwan) and Sweden (no Third World sales yet). Other potential clients who have expressed an interest in submarines for their navies include Malaysia, Thailand, Iran, Iraq, Saudi Arabia, and Nigeria. Saudi Arabia is currently negotiating for training submarines with several Western suppliers. Iran had previously ordered six 209s during the 1970s under the reign of the Shah. Fortunately, the order was cancelled after the Shah was dethroned. Otherwise, the 1987-1988 reflagged tanker escort operations in the Persian Gulf would have taken on a whole new dimension. If Iran and Saudi Arabia do acquire submarines, Iraq may eventually follow suit despite its very limited coastline (prior to its invasion of Kuwait). Submarines could provide an effective counter against a naval blockade being enforced by surface combatants.

Approximately 150 diesel submarines of non-Western origin can be found in various Third World navies. The Peoples Republic of China (PRC) alone has about 90 of these submarines, but less than half of them are considered operational. The vast majority of these submarines are ROMEOs produced by the PRC based on Soviet circa 1960 designs. China has since provided ROMEOs to Egypt and North Korea. North Korea has about two dozen diesel submarines, half of which are ROMEOs produced indigenously based on PRC designs. It is likely that North Korean ROMEOs produced in the late 1980s represent a signifigmt performance improvement over their Soviet counterparts from the 1950s. However, the most impressive non-Western supplied submarine in the Third World is the Soviet KILO that Algeria and India have received and that reflects the latest in Soviet conventional submarine design. It is unclear whether Cuba, Libya and Syria will eventually procure KILOs to replace/augment their FOXTROT and ROMEO submarines. It is equally uncertain what Third World clients the Soviets will support in the future. Arms exports have been a major source of hard-currency earnings for the Soviets in the past. H this remains the case for submarines, then Soviet exports will likely continue.

By way of summary, the number of modem Western origin submarines in the Third World will likely increase, perhaps as much as doubling in the next 10-15 years. The number of non-Western origin submarines may signiftcantly decrease if Soviet exports are curtailed and if the PRC is unable to maintain its large order-of-battle. Regardless of the overall worldwide numbers, the quality of the submarines (latest TYPE 209, ROMEO and KILO designs) will continue to improve.

Submarine Propulsion Developments
Air Independent Propulsion (AlP) technologies are being investigated that will significantly increase the submerged endurance capabilities for diesel submarines. These technologies are intended to provide secondary power sources (200-600 KW) for recharging the submarine batteries. For low speed operations ( 4-6 KTS), the batteries could remain ‘topped off’ as long as the stored oxidants or reactants last, i.e., potentially for 2-4 weeks or more. This reduces or eliminates the need for frequent snorkeling operations to recharge ship batteries and thus decreases submarine wlnerability to ASW prosecution. While operating at slow patrol speeds, the diesel submarine would only have to go to the surface for tactical events (e.g., periscope checks) and oxygen regeneration to maintain a proper atmosphere in the submarine.

Four AlP technologies are being actively pursued by Western manufacturers: closed cycle diesel engines, Stirling engines, fuel cells and low power nuclear reactors. aosed cycle diesel engines typically combine stored oxygen (either as a gas or in liquid oxygen form), a working gas, recycled exhaust, and fuel at the engine intake. Excess exhaust products are usually either compressed and stored onboard or discharged overboard. The Italian firm Maritalia relies on a gas storage toroidal hull to store oxygen gas (at 5000 psi) and exhaust from the closed cycle diesel system on its midget submarines or mini-subs, thus allowing more than a week of submerged endurance for a 150-ton submarine. The Dutch company RDM, in conjunction with the British firm Cosworth Engineering, is developing a closed cycle diesel system called “Spectre” that relies on liquid oxygen and a patented exhaust scrubber/water management/overboard discharge system. This system is purportedly efficient even at depths of 300 meters.

The Swedish Navy has successfully demonstrated the Stirling engine AlP technology on a modified NACKEN-class submarine. This system relies on liquid oxygen and a reciprocating external combustion engine. It features a continuous burning process in an external combustion chamber that is kept in overpressure to facilitate overboard discharge of exhaust down to 300 meters. The Gennan Navy, on the other hand, has successfully tested an alkaline fuel cell system on a modified TYPE 205 submarine. This system combines liquid oxygen and hydrogen (stored as a metal hydride) in a fuel cell to create a continuous chemical reaction that directly produces electricity without any combustion or heat transfer. As a result, the system is very efficient and potentially very quiet due to the lack of combustion and moving parts. Up to one month of submerged endurance should be possible.

The Canadian group ECS is developing an AlP System that relies on low power nuclear reactors, i.e., a “nuclear battery charger”. A similar system has been licensed for unattended operation at research facilities ashore. The maritime version of this system is referred to as AMPS for autonomous marine power source. Although no military sales have occurred, it is scheduled to be installed on the French SAGA-I commercial ocean submersible by about 1995. Unlike the other AlP systems descnbed, a nuclear battery charger could operate indefinitely – not being constrained by stored oxidants or reactants.

A number of Third World countries have shown interest in obtaining high power nuclear propulsion systems for their submarines. India, Brazil and Argentina have indigenous SSN development programs although Argentina’s effort has been on hold since 1988. It is unlikely that any SSNs will be indigenously produced in the Third World prior to 2010 (except in the PRC). However, some shortcuts are available to these countries. Several countries including Pakistan have shown an interest in the French RUBIS submarine (or its quieted variant AMETIIYSTE), the world’s smallest nuclear attack submarine. India has leased the CHARLIE SSGN from the Soviets. It is unclear what constraints will be imposed in the future on SSN sales or leasing arrangements by the USSR, France, U.K. or PRC.

Threat to Western Power Projectioa Forces and shipping
Submarines in Third World navies can be used for various warfare tasks including special warfare, mine warfare, anti-surface warfare and anti-submarine warfare. Swimmer delivery vehicles carry swimmers, mines or lightweight torpedoes on a skeg arrangement Mini-submarines are often designed to carry mines or launch torpedoes from conventional torpedo tubes. Two to four heavyweight (HW) torpedo tubes can be installed on minisubs of 150-300 tons submerged displacement. Anti-ship cruise missiles such as EXOCET or HARPOON could also be fired from these HW torpedo tubes. Mini-subs can also be used to transport and deploy swimmer/mine/commando delivery vehicles from a specially designed lock-in lock-out chamber. Larger diesel submarines (over 1000 tons displacement) typically have 4-8 HW torpedo tubes and 14-18 torpedoes or missiles. Heavyweight torpedo suppliers include West Germany (SUT/SST -4), U.K. (TIGERFISH), France (F-17P), U.S. (NT37E), Sweden(TP617), Italy(A184) and USSR(TYPE 53). Several of the Western supplied torpedoes are dual purpose and feature wire guidance, advanced active/passive acoustic homing, quiet electric propulsion and 250 kg warheads. The U.S. has provided submerged launch HARPOON to Israel and Pakistan; Egypt is due to receive this system in 1993. Other countries such as France with the SM39 variant of EXOCET are likely to pursue similar sales in the future. Both missiles and torpedoes have demonstrated lethality against surface combatants. EXOCET missiles have sunk (HMS SHEFFIELD) or achieved mission kill (USS STARK) on various surface ships. A small contact mine (100-125 kg warhead) nearly cut the USS SAMUEL B. ROBERTS in half, and two British MK 8 heavyweight torpedoes (340 kg warbeads) sunk the over 13,000 ton Argentine cruiser BELGRANO. The latter attack resulted in greater loss of life than the British suffered during the entire Falklands campaign.

The possible targets for Third World submarines range from merchant shipping to various naval combatants. Unescorted merchants or logistics supply ships transiting in confined sea regions would be relatively easy prey. Surface combatants operating in open seas would be more difficult. Submarines would generally be least susceptible to attack due to their inherent stealth and the lack of acoustic intelligence(ACINT) data likely to be available to most Third World adversaries. Thus, anti-submarine(ASW) operations against Third World submarines would often focus on the protection of surface forces, both shipping and combatants. U.S. attack submarines could make significant contributions to these ASW missions, but not if they are employed as the British did with their submarines in the Falklands.

The 1982 Falklands conflict is the best example of Western ASW operations against modem Third World submarines. The Argentines employed one modem submarine, a TYPE 209 diesel submarine named the SAN LUIS. It was operated by an inexperienced, newly assembled crew and equipped with Western supplied heavyweight torpedoes (SST -4 ASUW, MK 37 MOD 3 ASW). The SAN LUIS was on patrol for 6-7 weeks approximately 800 nautical miles from its base. It conducted two attacks against British warships. Both attacks failed reportedly due to fire control computer casualties and torpedo wire breakage, thus reflecting a lack of operational readiness, i.e., inadequate maintenance and unrealistic training. The British were very fortunate not to have lost a warship to torpedo attack, particularly since they failed to achieve a coherent ASW picture in the operating area. More than 200 items of ASW ordnance were expended, mostly against a sea full of false contacts and not the SAN LUIS. Numerous ASW assets were involved including two ASW aircraft carriers and more than a dozen frigates and destroyers plus associated ASW aircraft. Several British submarines were also deployed to the Falklands region but could not be integrated into the coordinated ASW operation.

In fact, these submarines were geographically separated to eliminate any possibility of fratricide and to allow ” ASW weapons free” for the main task force. In the Falklands campaign several controlling factors were apparent that tend to make ASW difficult against Third World adversaries. First, diesel submarines are inherently quiet when operating on batteries and represent difficult detection opportunities for passive sonars. Second, adverse (often unfamiliar) acoustic environments are all too common in Third World operational settings. Third, less operational and technical intelligence data may be available on the adversary than for the Soviets, particularly if the adversarial relationship is unexpected. Fourth, it is often a rapidly developing “come as you are” conflict and potentially involves long supply lines. Fifth, early catastrophic losses (e.g., sinking of the BELGRANO) can be an effective deterrent to the forces affected and potentially will undermine the popular support for the conflict. Not demonstrated in the Falklands, but important factors in other Third World contingencies nevertheless, are restrictive rules of engagement and concern for collateral damage. Near positive identification (whose submarine is that?) and unambiguous adversary intentions may be required. Without clear ID and establishment of intentions, target destruction may not be allowed and other measures will need to be taken to neutralize Third World submarines.

Third World ASW Requirements and Associated SSN Program Areas
Four examples of Third World ASW related requirements will now be given. First, it is apparent that there is a need for high SSN survivability (i.e., low risk of combat damage) while involved in Third World contingencies and limited conflicts. Future SSNs require appropriate self-defenses to counter a diverse variety of Western and non-Western produced ASW torpedoes and mines. Countermeasures development must be adequately supported by an intelligence data base on a more diffused threat than previously bas been evident for NATO/Warsaw Pact scenarios. The general requirements for quiet torpedoes (launch/running) to reduce counterattack potential and for low submarine signatures are clearly reinforced in Third World scenarios. Operations in shallow/confined seas, possibly tracking diesel submarines, magnify the importance of signature control in order to accomplish ASW missions with prudent risk.

Second, it is evident that there is a requirement to be able to track and possibly neutralize non-nuclear submarines (swimmer delivery vehicles, mini-subs, diesel-electric submarines, etc.). This implies that adequate cueing mechanisms must be in place to support SSN tracking operations against very low radiated noise signature targets, i.e., diesels operating on battery. This has implications for both C3 to exploit external cues and for innovative self-cueing mechanisms for SSNs. Both types of cueing may be required to keep track of diesel submarines and to determine if they pose a potential threat to power projection forces or other assets in the region.

To sustain SSN tracking operations against quiet diesel submarines will require a combination of SSN sensing mechanisms. “Full spectrum” passive acoustics may be a significant player but only if various noise sources characteristic of confined sea regions can be properly processed with the help of an adequate acoustic intelligence (ACIN1) data base. Currently, ACINT on non-Soviet diesels is limited compared to that collected on Soviet nuclear submarines. Active sonar or non-acoustic sensing may also have significant roles in allowing U.S. SSNs to track Third World diesel submarines.

“Neutralizing” a Third World submarine so that it does not pose an immediate threat to protected naval and mercantile units could be difficult under ROEs that prohibit destruction of the adversary submarine. An SSN assigned this task may have to resort to various methods of deception, harassment or disablement not previously anticipated against the Soviets.

A third requirement area relates to the need to develop a coherent tactical picture by the SSN, both to ensure efficient use of limited resources and to avoid collateral damage. Disabling or destroying a non-adversary submarine during an escalating crisis would have major repercussions. Questions such as what class of diesel submarine is that (ROMEO, KILO or TYPE 209) or whose ROMEO is that (Syria’s or Egypt’s) will be very difficult to resolve. Efficient use of limited ASW resources will not be possible if a high percentage of assets are wasted on false contact prosecutions (e.g., as was the case in the Falklands). Sonar beam patterns, transmit pulses, signal processing techniques, and displays must be designed to cope with dense coastal shipping, high bottom interaction acoustics and other unfavorable conditions associated with Third World regions. Tactical decision aids (1DAs) that are capable of exploiting near real·time oceanographic support wiU also contnbute to optimized use of SSNs and their sensors. Finally, effective acoustic training methods are needed that give sufficient emphasis to Third World diesel submarines or mini·subs (in addition to the focus on Soviet submarines).

A fourth requirement area relates to effective SSN coordina· tion with other naval assets. Secure, reliable Low Probability of Intercept/Exploitation (LPI!LPE) communications are needed for SSNs to ensure timely reporting of adversary submarine movements, thus allowing protected units to take appropriate defensive actions. Communications are also needed to allow timely receipt of tactical information by the SSN, ranging from local surveillance data to a change in ROE by higher authority.

In some Third World contingencies a variety of U.S. and allied naval assets will be employed in a constrained operating area and/or in a confined sea region. In this case it is neces· sary to develop a coherent force tactical picture (that the SSN contnbutes to) that will allow effective SSN integration into coordinated ASW operations. Otherwise, the Falklands solution will likely occur, that is, geographic separation and a limited ASW role for SSNs. SSN integration into force operations must be preceded by realistic operational training in coordinated ASW by the various players (ships, aircraft, submarines, surveillance assets). This must include exercises against diesel submarines (e.g., made available by our Allies) in marginal sea regions.

Modem submarines and weapons will continue to prolifer· ate in the Third World. Modem diesel submarines today are capable adversaries that pose a serious threat to power projection forces and other naval and mercantile units. In the future these Third World submarines will become even more capable (quieter, greater submerged endurance, advanced weapons), their crews will become more proficient, and improved infrastructure support will exist for Third World submarine operations. Various factors complicate ASW operations in Third World regions, and the resulting ASW requirements are not simply a subset of Soviet.derived requirements. The combined requirement to enhance strategic deterrence (hold adversary SSBNs at risk, enhance security of our SSBNs during port egress/ingress) and to enhance conventional deterrence in Third World contingencies and regional conflicts (hold adversary attack submarines at risk, enhance security to various forces) has the following broad implication: Submarine ASW will continue to require advanced technology solutions.

The reduced likelihood of a NATO/Warsaw Pact conflict provides an opportunity to focus more on a neglected military planning area – Limited Conflict Do not mistakenly assume that less advanced technology is required to deal effectively with Third World (vice Soviet) adversaries. However, do not assume either that the same technology solutions apply to both cases.


The last U. S. Navy Diesel-Electric Attack Submarine, USS Blueback (SS-581), was decommissioned on October 1, 1990 at ceremonies at the Naval SubmariM Base, San Diego.

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