By Pavel Rumyantsev
Torpedoes represent the main weapon of the majority of submarines, one of the most efficient attack instruments at sea during wartime. Clearly, the capabilities of torpedoes as the main weapon of submarines are one of the factors determining the efficiency of submarines as a weapons system.
TRENDS IN THE DEVELOPMENT OF TORPEDOES AFTER WORLD WAR II
While building its navy at the beginning of the Cold war, the Soviet Union concentrated its major efforts on producing a great number of submarines, since under the economic circumstances of those years the large-scale production of submarines was practically the only method of confronting naval threats. Later, beginning in mid1960s, the Soviet Union acquired a large ocean-going surface fleet, though submarines played and continue to play a leading role in the naval strategy of the national fleet. Therefore, their efficiency influences significantly the capabilities of the navy of the Russian Federation.
Apart from stealthiness, as well as different technical characteristics of submarines, one of the most important factors affecting efficiency of their actions is torpedo. The main emphasis for improving torpedoes after World War II in all countries, besides enhancing their basic characteristics (such as range and speed), was the development of homing guidance systems, which dramatically increased their combat capabilities. The torpedoes used by submarines and ships of the countries that fought in World War II were unguided, which significantly impaired their efficiency. Generally, in order to increase the probability of killing surface targets to acceptable levels, it was necessary to fire torpedoes in a “fan” volley. This approach resulted in the heavy expenditure of torpedoes to kill one target, making torpedo highly efficient only against the low-speed transport ships (which were the main targets of submariners at that time). Submarines were quite inefficient in fighting big surface ships with high traveling speed and maneuverability. Emergence of torpedoes with homing guidance systems (HGS) drastically enhanced their combat efficiency.
THE USSR ACQUIRED ITS FIRST HOMING GUIDANCE TORPEDOES IN 1961
Special requirements were developed for homing guidance systems of torpedoes in the navy of the USSR during the Cold War, as the large combat ships of the probable enemy were the basic targets for Soviet submarines, and they had to operate under conditions of NATO’s powerful antisubmarine warfare system. The HGSs of Soviet torpedoes had to feature maximum efficiency and in no way restrict the maneuvers of the submarine after launch. The fundamentally new 53-61 anti-surface ship torpedo, equipped with a unique homing guidance system with wake location, began to arrive in quantities to the inventory of the Navy of the USSR in 1961. The principle of such homing guidance system consists in the following. Special antennas periodically send hydro-acoustic pulses upward. When crossing the wake of the target ship, the characteristics of the received reflected pulse change, and the homing guidance system generates commands to the rudder controls. Then, the torpedo begins to pursue the target ship by periodically crossing the wake, moving along a sine curve with the aim of continuous searching for the wake. This “search” comes to an end under the bottom of the target ship with the engagement of the magnetic firing system. Until the end of the Cold War, torpedoes with this homing guidance system were the main system of warfare with enemy ships, and represented the most dangerous weapon to them, since they were practically undetectable by sonar countermeasure tools. However, torpedoes of this type have an essential drawback; they have to be fired at the stern of an enemy ship, after which they catch up with it, moving not along a straight line, but along a sine wave. The aggregate of these factors greatly reduces the distance at which a submarine can perform an efficient attack, and requires it to come quite close to its target.
In 1965, the Soviet fleet acquired the 53-65 torpedo, and four years later its upgraded version, 53-65K. This torpedo became the main armament of Soviet submarines, and a great amount of its kind was exported. Submariners like it very much for its high dependability and ease of operation. In addition, it is inexpensive to manufacture and has quite acceptable combat characteristics. 53-65K is capable of covering 19 kilometers at the speed of 43 knots. This torpedo is still the main weapon of Russian submarines, and in 2011, its production was resumed, now in an upgraded version. Despite the fact that this torpedo is half a century old, it will probably remain on the torpedo racks of Russian submarines for a long time.
“SUPER TORPEDOES” AGAINST AIRCRAFT CARRIERS
A huge torpedo featuring caliber of 650 mm was built specifically for fighting large surface ships of the probable enemy, mainly aircraft carriers. This torpedo, designated 65-76, was acquired by the navy of the USSR in 1976. All third-generation multipurpose submarines, which still make up the main element of Russian submarine forces, have been designed to use this torpedo and equipped with 650-mm torpedo launchers (TL), in addition to “standard” 533-mm launchers. So, for instance, the submarines of Project 945 feature two 650- mm and four 533-mm ТL, while the most numerous nuclear-propelled submarines in the present-day Russian fleet, Project 971, are outfitted with four 650-mm and four 533-mm torpedo launchers. The capabilities of torpedo 65-76 are immense. It is capable of covering 50 kilometers at the speed of 50 knots or 100 kilometers at the speed of 30–35 knots. The submarine can launch these torpedoes from a depth of 400 meters. This torpedo has been equipped with a warhead featuring the explosive force of 765 kilograms in TNT equivalent. This is sufficient to literally break a cruiser-class ship into pieces and inflict great damages to a strike aircraft carrier. Several of these torpedoes can kill it, whereas at least 10 “regular” torpedoes are required, according to experts, to kill a strike aircraft carrier of “Nimitz” class.
In 1991, an improved version of torpedo 65-76А, designated Kit, was added to the arsenal. Unfortunately, this torpedo became notorious in the present-day Russian fleet as the cause of the Kursk submarine disaster. These torpedoes have engines that run on highly volatile hydrogen peroxide, which requires strict adherence with the manufacturer’s instructions and directives during storage and operation. Unfortunately, such requirements were not always observed under the conditions in which the Russian fleet existed at the end of 1990s. As a result, a faulty torpedo ended up aboard the Kursk submarine and exploded during a firing exercise, which in turn caused detonation of the entire torpedo combat ammunition load and the death of the submarine within a matter of seconds. The tragedy of the Kursk led to the withdrawal of all 650-mm torpedoes from service, and Russian submarines lost their most dangerous weapon. It should be noted that if the torpedoes are properly maintained and stored they do not pose any danger, which has been proven by the extended experience of operating hydrogen-peroxide torpedoes in a number of foreign navies, in particular, in Sweden. In fact, the decision to withdraw 650-mm torpedoes from service was premature and reduced the fighting capabilities of Russian submarines significantly.
FIGHTING SUBMARINES: THE MERITS AND DRAWBACKS OF ELECTRICALLY-PROPELLED TORPEDOES
Along with the development of anti-ship torpedoes, works have been carried out on anti-submarine torpedoes. Unlike anti-ship torpedoes, anti-submarine torpedoes must have the capability to maneuver in two planes, and an active acoustic HGS for certain destruction of the enemy submarine. A basic element of such a HGS is a small sonar apparatus installed in the nose of the torpedo. The active acoustic homing guidance system controls the torpedo on the basis of acoustic pulses emitted by the sonar apparatus and reflected off a target.
In 1965, the electrically-propelled torpedo SET-65 was added to the arsenal of the Soviet fleet, and became the main tool for Soviet submariners in fighting the probable enemy’s submarines. The main and the most mass-produced version of this torpedo was SET-65III, equipped with an acoustic active-passive Sapfir HGS. This homing guidance system, in turn, became the main HGS for anti-submarine torpedoes. It was used to furnish all subsequent anti-submarine and universal electrically-operated torpedoes built in the USSR.
Electrically-operated torpedoes feature a number of merits and drawbacks. On the one hand, they ensure a low level of noise due to being propelled by electric motors fed by powerful storage batteries, and they are completely traceless, unlike gas-steam torpedoes. However, they feature a significantly lower speed and traveling range than gas-steam torpedoes, while their storage batteries have to be permanently kept in charged condition, otherwise, the range and the traveling speed are reduced.
By early 1970s, new-generation torpedoes began to appear in the naval arsenals throughout the world. They were universal, capable of being used equally efficiently against surface ships and submarines, and were equipped with remote control systems, as a rule, complemented with an active acoustic HGS. Such torpedoes are controlled by wire from aboard the shipcarrier or the submarine-carrier, which helps easily counteract any maneuvers by the target. The American Mk-48 universal torpedo, which appeared in U.S. arsenals in 1972, became the shining example of such new-generation torpedoes. Its characteristics were striking at the time; it was capable of covering 40 kilometers at the speed of 50 knots; it had a highly-efficient remote-control system, an active-passive acoustic HGS with the capability of multipurpose attack. In case of a miss, the torpedo could circle and perform a new search for its target, doing so until the target was killed or the torpedo ran out of power. The Mk-48, which has been modified seven times, has become the main weapon of American submarines.
The first universal torpedo TEST-71 of the remote-controlled version of SET-65 torpedo was added to Soviet arsenals in 1971. In 1980, the universal torpedo USET-80 was added, and later, its modified version, USET80K, was adopted. As far back as the early 1980s, the USSR began to lag behind in the field of torpedo development, particularly, in the field of universal torpedoes. They were electrically-driven and their merits did not compensate for their drawbacks. But the main thing was that the remote control systems of Soviet torpedoes significantly lagged behind Western analogs. As far back as the 1970s, hose reels have been used in NATO navies for torpedo remote controls. A reel with a remote control wire was located in the torpedo launcher and got “rewound” as the torpedo moved forward. After launch, the ability of the submarine to maneuver was in no way restricted.
In Soviet torpedoes, a reel with a remote control cable was located in the torpedo proper. It greatly limited the combat capabilities of the torpedo. First of all, after launch, the submarine was unable to maneuver intensively, or else the control cable would break. In addition, in certain conditions the impact of water streams at high speeds could lead the reel wires to twist and break. Secondly, the application of the so-called towed reel did not make it possible to carry out collective torpedo fire, and in fact excluded the application of the remote control at shallow depths when attacking a surface target. In this case the highest level of automation of Soviet submarines, and in particular the automatic loading system of the torpedoes, which required the arrangement of reels in the torpedo, became a negative feature of the weapon itself. In order to make possible use of the remote control hose reel, it had to be located in the torpedo launcher, and after the torpedo attack it had to be removed manually, which was in contradiction with the requirements of the Soviet fleet command.
HOW THE TORPEDOES’ INSUFFICIENT EFFICIENCY PREVENTED THE ARGENTINEAN NAVY’S SUCCESS IN FALKLAND’S WAR
A shining example of how the efficiency of torpedoes can influence the combat capabilities of submarines was the Falklands war. In the course of combat operations, the Argentinean submarine S-32 San Luis (submarine of type 209 of German make, which was state of the art at that moment), armed with SST-4 German-made torpedoes, was able to secretly enter the waters around Falkland Islands controlled by the British fleet, despite the fact that according to reconnaissance data the British knew about it, and conducted an intensive search using the efforts of ships and antisubmarine helicopters. The submarine successfully launched a torpedo attack on one of the British ships (most probably, the destroyer leader Brilliant), but the remote control wire broken in the torpedo and it failed to hit the target. As the only Argentinean combat ship in the conflict area, the submarine attempted a new attack on May 11, 1982 after taking position close to Sao Carlos bay (a strait between the two biggest islands of the Falklands archipelago), and launched a torpedo at one of the destroyer leaders, the Alacrity or the Arrow (it is not known exactly which of them was the target). The attack also failed, probably for the same reason.
It should be noted that these British destroyer leaders were carrying out an extremely important mission: disclosing coastal defense and liquidating the threat of mines in the Sao Carlos strait with the aim of determining the possibility of a beachhead assault (the ships, in fact, had to “check” for the absence of mines in the strait using their own hulls, fortunately for the British there were no mines detected). As a result, Admiral Woodward, the commander of the British squadron, decided to perform a beachhead assault from this strait, where the Argentineans did not expect it, which led to victory in the war. The successful attack of the British nuclear submarine Сonqueror, which sank the Argentinean cruiser General Belgrano (that became one of the strongest shocks for Argentine in the course of the Falkland Islands war), raises interest. Despite the availability of modern Mk-24 electricallydriven remote-controlled torpedoes, the commander of the British submarine decided to attack the Belgrano with World War II-vintage unguided Mk8 torpedoes, probably because he did not have much confidence in the new torpedoes.
THE 1990S HAMPERED THE DEVELOPMENT OF RUSSIAN TORPEDOES FOR SOME TIME
At the beginning of the 1990s, the situation with torpedoes in the Russian fleet was grim, despite the fact that quite a large number of new submarines were inherited from the USSR, and these submarines featured excellent technical characteristics and lower noise emission than the American analogs. The available anti-ship torpedoes had dramatically lost their efficiency by that time; the efficient simulators had been developed by NATO navies, making it possible to divert with Russian torpedoes with wake locating systems. The lag in the development of universal torpedoes, remote-controlled and homing-guidance systems had grown worse and worse. At the time when torpedoes had been improved in NATO’s navy, the Russian fleet had to forget about new torpedoes, contenting itself with the decade-old models, albeit partially upgraded, already in its arsenal.
The situation has been partially compensated by the presence of torpedo-carrying missiles in Russian submarines, which were not available with the submarines of any other fleet. Practically all present-day nuclear submarines of the Russian fleet of design 945А Kondor and design 971 Shchuka-B and the cruise missile submarines of design 949А Antei are armed, apart from torpedoes, with RPK-7 Veter missile antisubmarine weapons systems, which were added to the arsenal in 1984. The system consists of a special missile, 86R, with a small UMGT-1 torpedo used as a warhead. After entering data about the approximate position of the enemy submarine acquired by the submarine’s sonar system (or using information transmitted to the submarine from an external weapons director), a torpedo-carrying missile is launched, from depths as low as 100 meters. After leaving the torpedo launcher, a starting engine fires the missile to the surface, and then the propulsion engine starts and the missile, controlled by an inertial navigation system, flies to the area of the enemy submarine’s location in a matter of seconds. Then it drops a small-size torpedo installed in the nose, which parachutes to the surface. Once it’s in the water, the torpedo begins to search for the target, using its active HGS. The maximum flight range of torpedo-carrying missile equals 100 kilometers. The traveling distance of the UMGT-1 torpedo does not exceed 8 kilometers, but taking into account the speed at which it gets delivered to the area of the enemy’s submarine location, that is of no particular importance.
The torpedo-carrying missile is enormously efficient in fighting enemy submarines; while it is possible to maneuver away from a regular torpedo, which is hardly possible when the torpedo is delivered by air directly to the target.
PROSPECTS OF DEVELOPMENT OF THE RUSSIAN TORPEDO: WILL PHYZIK LEAD THE WAY OUT OF STAGNATION?
The chance to refocus on the development of torpedoes in Russia appeared only by the mid-2000s. A new torpedo, UDWHGT (Universal Deep-Water Homing-Guidance Torpedo) was demonstrated in 2003 at the International Maritime Defense Show in Saint Petersburg. Its development began as far back as 1986 and it was supposed to end the lagging of the Soviet fleet in torpedo weapons development. According to public sources, quantity production of the torpedo designated Phyzik-1 was launched in 2015. UDWHGT features characteristics comparable with torpedoes of many foreign navies. Phyzik-1 has a thermal steam-gas engine enabling it to travel 40 kilometers at the speed of 50 knots, or 50 kilometers at the speed of 30 knots. The torpedo has a remote control system with an active-passive HGS (with the range of response to surface targets equal to 1,200 meters, and 2,500 meters to submarines) and an additional new-generation wake locating system. The HGS is also able to create a model of the tactical situation at the moment of launch, superimposed over a digital map of aquatic area (depths, bottom relief, etc.), based on the data of tactical situation that gets updated from aboard the submarine. However, judging by photos repeatedly demonstrated at different naval exhibitions, the torpedo is equipped as before with the towed reel with the remote control system wire, which imposes restrictions on the submarine’s ability to maneuver after launch, and restricts the possibility of collective fire.
Thus, a key problem of all Soviet remote control torpedoes has not been resolved in this torpedo. Still, its efficiency against surface targets is rather high due to the availability of a wake locating system that works according to new physical principles (wake locating is effected by means of optical methods) and is practically undetectable by modern acoustic countermeasures.
The new Phyzik-2 was added to the Russian Navy in July 2017. According to open source data, this torpedo is an update of Phyzik-1, and according to indirect data it has received a remote control hose reel. By all appearances, characteristics of Phyzik-2 are approaching those of the latest versions of the American Mk-48. Practically, in the course of the current decade, Russia has managed in many respects to close the gap in the field of torpedoes.
First of all, the cutting-edge, fourthgeneration multipurpose submarines of Project 885 Yasen, and subsurface launching platforms of Project 955 Borei will receive new torpedoes, but plans are to equip the older submarines of the Russian fleet with the new torpedoes, as well. The majority of new Russian submarines should begin to be put into operation by the Russian Navy starting in 2018. Unlike their predecessors, the parent submarines of these designs, which had to be armed with the obsolete USET-80 and SET-65 torpedoes, will now receive the most updated models. Featuring the highest degree of stealthiness and combat stability, the new Russian submarines armed with the latest torpedoes capable of consistently hitting both subsurface and surface targets of a probable enemy, will be capable of operating even in the zone of full superiority of hostile antisubmarine forces, delivering quite painful blows to an enemy by means of powerful torpedo and missile weapons.