Torpedo has been a fearsome weapon in Naval warfare due to its ability to sink ships and submarines with one shot. The modern torpedo enables submarines to defeat surface and undersea threats and at the same time gives surface ships and aircraft the means to reach beneath the surface and attack submarines.
The threat to Surface ships is also magnified through more destructive torpedoes, capable of counteracting evasive maneuvers even in shallow waters. Threat is also increasing as more and more capabilities are being added to torpedoes like larger effective range that improve surprise effect capability, higher speed, stealthier, and more lethal. They also remain controlled from the launching submarine, which also increases its hit probability. Moreover, performance acoustic heads in addition to faster processors, gives the torpedo high target discrimination capabilities and hit probability.
A torpedo hit can be potentially catastrophic for a submarine underwater as the destructive effect of the warhead is compounded by the pressure of the water at depths of 100 metres or more. Submarines can face torpedo attack from other submarines, surface warships or anti-submarine helicopters and aircraft.
Therefore, torpedo defence systems have become essential systems for high value assets like surface ships and submarines which not only carry expensive equipment and weapons, but also a high number of trained crew, to complete their missions. The traditional countermeasures and stand-alone capabilities, can achieve only some weak results, are not enough to ensure the required integrity of ships under torpedo attack. Therefore new torpedo countermeasures system are being developed and also becoming integrated to achieve its goal to avoid a torpedo impact on their own ship.
Rising threat due to Modernizing of Torpedoes
Depending on the size, torpedoes are classified as heavy-weight and light-weight torpedoes. Most of the navies operating submarines utilize HWT as their main weapon against surface ships. Modern HWT Torpedoes are becoming extremely dangerous as a result of new capabilities integrated into them which is making them faster, stealthier, and lethal using new engagement concepts.
Modern torpedoes referenced will include those capable of being launched at any depth, with self-contained processors and acoustic detection devices, carrying acoustic or magnetic fuses, and finally with the capability to remain connected to the launching submarine by a control cable during all or part of the run. More efficient propulsion systems, which in addition to high endurance batteries and navigation control devices, permit the weapon to achieve speeds up to fifty knots, making it able to counteract the highest speed of an evading surface targets.
Torpedo payloads have also become destructive with multi-mode detonation, offering both bulk-charge and directional alternatives. New acoustic and magnetic influence fuses produce the torpedo explosion under the ship’s keel, generating much more damage than before. They will provide higher lethality and use increasingly energetic materials to create more powerful effects, while still meeting the requirement for insensitive munitions. This provide the potential for weapons to be smaller and lighter, with increased range capability or room for additional sensors and signal processing.
Higher effective range, which improves the time the weapon can spend in the water prior to the attack, performing maneuvers either to remain undetected, searching for targets and conducting their own search and re-attack programs. This imposes a greater challenge to surface ships, because submarines do not need to approach as close as before to launch torpedoes, making them harder to detect and allowing them to keep the initiative.
At the same time, propellers associated to those systems were also enhanced, making the whole weapon not only faster, but also harder to detect with normal acoustic hull- mounted sonars. A stealth weapon that cannot be heard until very late in the encounter will delay the threat’s detection of the torpedo and impair its ability to respond effectively with either countermeasures or return fire. This will greatly increase the probability of killing the enemy and avoiding a potentially lethal counterattack.
Many navies led by Russian Skval have developed very high speed torpedoes which using “supercavitation” principles converts them into underwater missile with the ability to kill a target before it can react. Such a weapon would be well suited for close-range submarine encounters. With multi-purpose configurations, it could be used not only for anti-submarine warfare, but also as an anti-torpedo torpedo, or for defense against high-speed surface craft.
The older torpedoes use gyroscopic guidance for either straight running or pattern running. However, the modern torpedoes rely on acoustics for homing and attacking a target. Torpedoes work either in passive, active or mixed modes. Torpedoes usually follow helical pattern search. Torpedoes are limited by their frequency of operation due to their small size as compared to the targets. Both active and passive homing ranges are restricted by their operating frequency. To compensate for these short ranges, wire guidance is used for extending the range. Modern torpe-does have two-way wire communication with the torpedo fire control system.
In active homing, the acquisition range is generally set by its ping rate. The general detection process is an energy detection and modern torpedoes do have correlators and FFT processing. Passive homing is more effective against surface ships because surface ships create considerable noise due to propulsion. Passive homing torpedoes are more effective against surface targets, however, they are not effective against submerged diesel elec-tric submarines. The torpedo homing frequencies are generally in the high frequency band because of the size limitations of the torpedo homing head. They use variable pulse widths and multiple transmission waveforms.
Enlarged wire guidance capability, through optic fiber cables, giving the capability to the torpedo to remain connected to the launching submarine for greater distances and exchanging high volumes of information. This helps to neutralize the main problem of the fire-and-forget weapons, which in the case of a bad pre-setting, they can miss their targets after being launched. With this kind of device ships’ evasive maneuvers can be better avoided, because specialized operators can correct the torpedo’s navigation parameters at any moment, as well as to re-program its run according at any moment to best follow the attacked ship.
Self-homing programs associated to advanced acoustic heads (incorporated sonar), which in case of a wire-guidance cable cut, will allow the torpedo to continue its own target approximation, by using different search and attack patterns. Inertial navigation systems connected to high precision depth sensing devices provide tri-dimensional navigation capability and high accuracy in shallow waters, which contribute to performing attacks close to ports and coast lines, where surface ships normally search for anti-submarine (ASW) protection. Improved electronics, linked to fast signal processing, which provides high target discrimination and anti-acoustic countermeasures capability (ACCM) to the torpedo.
The operating environment for torpedoes continues to change. Undersea networks for communications, sensors, and tactical engagement continue to develop through advances in acoustic communications and fiber-optic links. The Next Generation torpedoes have networked communication capabilities and able to fuse data from platform, weapon, and benefit from intelligent control. They may be deployed not only from submarines, but also from unmanned undersea vehicles that become remote firing platforms and keep the submarine out of harm’s way.
Torpedo Defense system(TDS)
Torpedo attack is a covert operation. Modern heavy-weight torpedoes attack a ship either in autonomous or wire-guided mode. Torpedoes always run at higher speeds compared to ships or submarines. Protecting war ships from torpedo attack is considered as the most challenging task in Anti-Submarine Warfare. The main functions of a Torpedo Defence System (TDS) are to detect, localize and to take evasive and counter actions against an attacking torpedo.
The two essential functionalities of a torpedo defence system are to detect the torpedo and to help the platform to evade its attack. There are two approaches for the latter task: one is hard-kill and the other is soft-kill. In hard-kill, the attacking torpedo is destroyed by another torpedo, which is an anti-torpedo torpedo. In soft-kill, the torpedo is lured away from the platform and its trajectory is controlled using decoys till its battery-life gets exhausted.
The soft-kill method is generally done in a layered manner wherein the responsibility to defend the torpedo is passed on to different lay-ers. Detection, tracking and classification of torpedo targets is the first step in torpedo defence. Identification of the torpedo threat parameter is the next step. Executing es-cape manoeuvre and tactical deployment of available countermeasures are the final steps in torpedo defence
The following objectives are to be essentially met by the TDS: panoramic detection and tracking of all targets in the area of operation at max-imum range, classification of torpedo targets at the earliest, localisation of torpedo targets using Target Motion Analysis (TMA) algorithms, threat analysis and recommendation of evasive manoeuvres and use of counter measures, effective use of countermeasures to evade torpedo attack.
Therefore Navies are developing an integrated system which can detect the torpedo early, react with the ship, and at the same time launch the best configuration of jammers and decoys in order to confuse the weapon’s logic as much as possible. Sensors, independent from the ship’s main sonar, are used in order to detect, classify and calculate the trajectory of the incoming torpedo.
Central processing unit, which receives information from the sensors and provides advice on the best maneuver the ship should perform, in order to increase distance with the torpedo, as well as to define the best combination of jammers and decoys to confuse the torpedo as much as possible. Jammers and decoy launchers, which should be fired in a programmed sequence, with the aim to divert the torpedo, while the ship continues to enlarge distance.
A generic contemporary torpedo defence system comprises of five distinct elements: a set of acoustic sensors which detects an inbound torpedo threat, a highly automated target classifier to identify torpedo targets, target localization algorithm to localize torpedo targets, an automated information processor for threat evaluation, and tactical advice for evasive manoeuvring and deployment of countermeasures, a range of countermeasure solutions such as towed decoys and expendable decoys designed to lure the incoming torpedo away from its intended target (soft-kill) or destruction of the torpedo (hard-kill).
Current torpedo countermeasures
Conventional countermeasure devices include sonars mounted on the ship’s structure (known as hull mounted arrays, HMAs), towed countermeasures arrays, maskers , static jammers or target generators launched from the ships, and anti-torpedo devices. Conventional actions are maneuvers executed by the ship to avoid an incoming torpedo, including changes of speed and course.
The most important action to be performed in order to apply any torpedo countermeasure is to detect the incoming torpedo; also the higher detection range, the greater time we will have to react against the weapon. Torpedo defence systems typically follow the principle of layered defence which utilizes detection, classification, localization, workout escape tactics and deployment of countermeasures. The detection system is further divided into outer and inner layer defence with respect to the ranges of detection. TDS should be capable of detecting all the targets around the platform under all operating scenarios. Long-range detection including left-right ambiguity resolution can use a towed array sonar, whereas the hull-mounted sonar helps detect a torpedo at closer ranges and also from the head sector
HMAs installed on board warships can operate mainly in two modes in order to perform underwater detection, active or passive. Broadband passive sonar systems found on modern submarines identify a target by contrasting the broadband energy signal-to-noise ratio (SNR) with quieter background noise. This contrast is displayed as different shades or colors on the sonar screen forming traces that waterfall down from the top. Broadband acoustic masking devices that interfere with a sonar’s ability to differentiate background noise from a contact, like the Naval Acoustic Electromechanical (NAE) Beacon Mk 3, are the simplest of torpedo countermeasures.
This saltwater activated masker is ejected from the submarine and a float is released that tethers the device to a specific depth. A thermal battery powers its motor and electronics, which create the broadband noise. This produces a loud acoustic signature that spans the spectrum of a broadband sonar system, effectively raising background noise above a target’s SNR, “wiping” the sonar operator’s display in one solid color with no contrast. As such, they cannot delineate targets from the noise.
As the main priority for the HMA will remain always on trying to detect submarines before torpedoes, it will normally be operated in active mode, because their radiated noise level is very low, and in passive mode its discrimination ability is difficult. This is because HMAs are very affected by the ship’s own radiated noise, so when sonars operate in passive mode, they are very perturbed, impacting negatively in the process of target discrimination. Therefore modern surface ships continuously perform submarine search and install an independent torpedo sensor for capability of torpedo early warning.
Torpedo towed countermeasures are devices that are placed some meters behind the ship propellers, with the aim to perturb torpedoes’ acoustic heads. Static jammers and target generators (decoys) launched individually from ships are very similar to the towed countermeasures; the only difference is that they do not remain attached to the surface ships. Jammers generate high level of noise in a broad frequency band to confuse the torpedo’s acoustic head, while target generators create new targets close to the ship in order to confuse the torpedo processing system.
Maskers have a short operational time and grow quieter as they lose power. It is common to deploy multiple maskers with different start time delays. This gives the evading submarine more time before the masking field expires. They are not effective against most modern torpedoes, such as the Russian UGST or the Black Shark. This is because maskers will cover a submarine’s evasion maneuver from the opponent’s broadband sonar system, but will not reliably hide a submarine from the torpedo’s active or narrowband sonar search modes.
Sonar Jammers, such as the United States Navy’s Acoustic Device Countermeasure (ADC) Mk 4 Mod 1, an expendable 6.25-inch diameter, 120-pound (54.4kg) countermeasure, produce wide range tones designed to confuse a torpedo detection logic with a large number of false targets. This triggers a target verification algorithm within the torpedo’s homing logic and restarts it continuously with multiple new targets every second. This result is the torpedo circling the jammer verifying targets that do not exist while the actual submarine exits the search area.
The main problem associated to these devices is that they cannot move, generating a static high level radiated noise source in the water. Modern torpedoes can process the target information and distinguish static sources, labeling them as not valid contacts. Finally, although decoys can give some more time to the ships to perform a maneuver and try to evade the torpedo, it will not assure the required survivability, because the ship will increase its speed, what will bring as consequence an increment on its radiated noise. This will be detected either by the submarine or the torpedo.
Most modern torpedoes, such as the Royal Navy’s Spearfish, have modes to defeat this kind of jammer and older less capable torpedoes can use guidance commands sent over the long trailing wires connected to the launching submarine to reset the torpedo’s search mode. However, this latter method requires direct input from the submarine’s fire control system operators.
Anti – Submarine Warfare capability of the Indian Navy has received a major boost with the conclusion of a contract for Advanced Torpedo Decoy System capable of being fired from all frontline warships. Design & Development of this anti-torpedo decoy system has been undertaken indigenously by DRDO labs – Naval Science and Technological Laboratory (NSTL) and Naval Physical & Oceanographic Laboratory (NPOL).
Modern Torpedo defence measures
Today’s anti-torpedo technology, such as Russia’s Paket-E/NK close-in anti-torpedo torpedo, Israel’s Torbuster, and the United States Anti-Torpedo Torpedo Compact Rapid Attack Weapons program (ATT CRAW), are making conventional torpedoes obsolete. Since conventional devices carried by those units are not enough to provide an adequate defence against this type of weapon. Navies is arming ships and submarines with high-tech torpedo defense technology able to detect, classify, track and destroy incoming enemy torpedoes.
Submarine Scutter (SUBSCUT) and Launched Expendable Scutter (LESCUT) are reactive decoys built by Ultra Electronics Ocean Systems and Rafael of Israel. SUBSCUT is pre-loaded into internal signal launchers or external launchers—launch tubes that house the countermeasure devices, and can be automatically deployed upon torpedo detection.
The decoy will hover between a depth of 10 and 300 meters listening for the incoming torpedo. A torpedo’s active sonar is analyzed by the decoy and classified. SUBSCUT customizes its own acoustic decoy transmission to the specific type of incoming torpedo, including the Doppler effect. Doppler effect is important to deceiving torpedo logic because it is one of the many checks the torpedo circuits can make during target verification. When the internal battery runs out, the decoy erases its software and sinks. LESCUT is the surface ship counterpart to SUBSCUT and is launched with a rocket motor from a chaff tube topside into the water.
The Submarine Countermeasure Acoustic Device (SCAD 102) is used by the Royal Navy’s ballistic missile submarines and the Astute class of nuclear fast attack submarines (SSNs). This four-inch diameter, self-contained, internally-mounted torpedo countermeasure has the multirole capability. It is mission programmed before launch and is capable of jamming and decoying next-generation torpedoes, such as the Mk 48 Advanced Capability (ADCAP).
Ultra Electronics has created the Type 2070 surface ship torpedo defense (SSTD) system. This next-generation torpedo countermeasure employs both active and passive methods that reliably decoy and destroy incoming torpedoes. Details as to how the Type 2070 does its job remain highly classified.
To respond to the “countermeasure homing” abilities of modern torpedoes, such as target verification and frequency discrimination, Leonardo has created the C303/S for submarines and C310 for surface ships. C303/S is a 12-barrel, external, pneumatic countermeasure launcher that shoots a 3.7-foot-long, 33-pound, three-inch diameter stationary jammer, and a five-inch Mobile Target Emulator (decoy).
CANTO torpedo countermeasure
CANTO represents a breakthrough in the field of torpedo defence. It is designed to protect any platform, submarine or surface, against the most advanced torpedoes and the previous generation of torpedoes as well. CANTO is ordered by the French Navy to protect its SSN and SSBN and by the Brazilian Navy to protect the new SSK fleet. CONTRALTO-V® is composed of several subsystems: the reaction system, which suggests an optimised evasive maneuver and deploys the countermeasures effectors; the deployment system fitted to several types of launchers (mortar, rocket, pneumatic) the acoustic torpedo CANTO® countermeasure
As soon as a torpedo alert is declared on-board, CONTRALTO-V® will suggest an immediate deployment of the CANTO® countermeasure and evasive maneuvers based on the ship’s capabilities including its speed, manoeuvrability, and environmental data. Characterised by a high maximum speed, extended wire-guided range and improved acoustic and ACCM capabilities, CANTO countermeasure acts completely independently of the torpedo threats thus offering a protection against numerous simultaneous torpedo attacks even in case of unknown torpedo threats.
Unlike the classical decoys aiming at seducing the attacking torpedo by recognizing its acoustic signal and reproducing one false target, CANTO is based on dilution/confusion principle. CANTO® is a broadband active acoustic countermeasure. It is designed to saturate the torpedo data processing system by emitting specific and smart acoustic signals, in the all torpedo frequency band in active and passive mode. Its mission consists in exhausting the threat by creating and renewing hundreds of targets strongly increase the operational capability and survivability of the surface vessels.
US Torpedo Defense Countermeasure technology
The emerging Surface Ship Torpedo Defense technology includes the Anti-Torpedo Defense System, or ATTDS and an SLQ-25 Acoustic Device Countermeasure; the ATTDS consists of a Countermeasure Anti-Torpedo program and Torpedo Warning System.
Towed decoys are common on most warships. Even the battleship USS Iowa deployed the AN/SLQ-25 Nixie system. Towed decoys employ both a broadband masker that generate more noise energy than the target ship and an active pulse transmitter that returns a torpedo’s active sonar ping at two to three times more amplitude than received. This attracts the torpedo to the towed decoy where it will circle until it runs out of energy. This is a better option than expendable countermeasures because if power is applied to the towed decoy, it will run continuously and can be reused. Expendable countermeasures have seawater batteries that last between six and 45 minutes. Modern towed decoys can also act as torpedo early-warning sensors and alert the towing vessel of incoming weapons before their hull-mounted sensors detect them.
The AN/SLQ-25 Nixie and its variants are towed torpedo decoys used on US and allied warships. It consists of a towed decoy device (TB-14A) and a shipboard signal generator. The decoy emits signals to draw a torpedo away from its intended target. The Nixie attempts to defeat a torpedo’s passive sonar by emitting simulated ship noise, such as propeller and engine noise, which is more attractive than the ship to the torpedo’s sensors.
The AN/SLQ-25A utilises a fiber optic tow cable (FOTC) and a 10-horsepower RL-272C double drum winch. The AN/SLQ-25C System is an upgrade to the AN/SLQ-25A system. The AN/SLQ-25C incorporates improved surface ship torpedo countermeasures with the addition of new countermeasure modes along a longer, more functional tow cable.
The AN/SLQ-25B includes equipment of the AN/SLQ-25A and incorporates a towed array sensor to detect submarines and incoming torpedoes. The AN/SLQ-25B also incorporates additional active sonar decoys by receiving, amplifying, and returning “pings” from the torpedo, presenting a larger false target to the torpedo.
Based on technology under development at ONR, a 6.25 inch-diameter self-protection weapon is under study for the defense of surface ships and submarines using supercavitation technology. Maximizing the survivability of the warfighter is crucial, and self-defense systems are necessary to ensure that all platforms have the capability to protect themselves from attack. Anti-torpedo torpedoes will provide our future platforms with an additional defense capability. Their primary mission is to destroy incoming torpedo threats that may have gotten through a countermeasure field.
Leidos to develop acoustic countermeasure to provide torpedo defense for Navy submarine fleet
In February 2019, the United States awarded a contract to develop a 3-inch version of the ADC Mk 4, called the ADC Mk 5. This will decrease the operational cost of the ADC program due to each device being stored within the submarine pressure hull instead of externally. An external ADC has a 12-year replacement lifespan, but only a two-year operational life after it is installed into the external mount.
Phase three of this contract explores the feasibility of automated underwater vehicles deploying torpedo countermeasures. This gives the attacking submarine more tactical flexibility because he can prepare the battlespace before an attack with numerous automated mobile decoys that move away from the submarine’s position. Testing of the system is taking place on naval ranges off the coast of Washington, California, Virginia, and at the Atlantic Undersea Test and Evaluation Center (AUTEC) in the Bahamas.
The jammer is supported by a floating buoy that deploys a cable submerging the jammer to its most effective depth for the environment. The Mobile Target Emulator (MTE) will move away from the jammer responding to the incoming torpedo’s active pings as if it is a valid return. The doppler of the moving decoy and high SNR response is sufficient to lure the weapon away for a short time. When the weapon realizes it is following a decoy it is likely to return to the jammer and not the target. The C303/S launcher can be manually or automatically fired upon torpedo detection. The system will give a recommended evasion course that moves away from the mobile decoy.
Officials of the Naval Sea Systems Command in Washington announced a $13.9 million contract to Leidos on Thursday to design, build, and test an acoustic device countermeasure (ADC) called the ADC MK5. The ADC MK5 project is part of the Navy’s Next-Generation Countermeasure (NGCM) program to replace existing ADC MK 3 submarine acoustic countermeasures systems.The objective of the NGCM program is to insert new countermeasure technologies into the submarine’s defense against threat acoustic-homing torpedoes. The key new capabilities NGCM brings are: adaptive countermeasure (ACM) technology with full duplex capability and mobility packaged in a three inch diameter body.
The ADC MK 5 is a three-inch diameter expendable device that is submarine launched from internal signal ejectors and Countermeasure Set, Acoustic (CSA) external launchers. The ADC MK 5 is an acoustic torpedo countermeasure with advanced features which can be employed as a static or mobile device and uses Adaptive Countermeasure (ACM) technology. The ADC MK5 will be re-programmable to operate together with U.S. and allied torpedoes or anti-torpedo systems, and will be able to change tactics in response to changing tactical or environmental conditions via the acoustic communication link.
The countermeasures will have advanced tactical embedded processors and a built-in threat torpedo classifier. The system’s new technologies will include mobile countermeasure operations and tactics; acoustic communications; group behavior and the ability to work against incoming torpedoes cooperatively; the ability to classify incoming torpedoes; full-duplex receive and transmit sensor capability; and single-crystal transducers.
Ultra Electronics is developing the Next Generation Countermeasure (NGCM). This 3-inch device can be internally launched and will swim away from the launching platform and provide tactical information via an acoustic communication link and updates between ships and submarines in the battlespace. The NGCM will act as an autonomous full-duplex mode acoustic communication link and torpedo jammer or decoy if, necessary.
The 3-inch Swimmer Mk 2 device is in development, it provides more tactical capabilities and can be launched externally. This gives submarine commanders more tactical options. Devices such as the NGCM expand sonar detection range, act as guards against counter-attack, and can provide broadband masking while the submarine repositions itself.
Russian Anti torpedo decoys
Russia’s Paket-E/NK anti-torpedo system is designed to engage torpedoes or submarines inside 800 meters. This fast-reacting countermeasure consists of an externally mounted rotary launcher of eight intercept devices, a Paket-E control system, and a Paket-AE sonar set. The system can automatically alert on an incoming torpedo, calculate its path and launch a torpedo disabling anti-torpedo. It provides ships with unique anti-submarine and anti-torpedo capability. This point defense approach is employed if traditional evasion is unsuccessful.
Rafael’s Torbuster is a mobile decoy that is launched from an external launcher. It mimics the incoming weapon’s active sonar creating a false target. The system will calculate the torpedoes range and when it reaches the closest point of approach, it self-detonates a charge capable of damaging or destroying any nearby weapon.
Rafael submarine anti-torpedo countermeasure systems
Rafael describes SHADE as a “torpedo defence suite” for submarines that will protect these underwater vessels from all types of acoustic-homing torpedoes, which rely on sonar signals. Rafael notes SHADE “will be the first system in the world to employ a combination of soft-kill and hard-kill decoys, thereby providing a robust and effective defence against modern torpedoes”. Hard-kill decoys are weapons that impact an incoming torpedo or missile directly and destroy it, while soft-kill decoys use radio waves or sound waves to ‘deceive’ an incoming torpedo or missile.
Shade torpedo defence suite that protects submarines from attacks by all types of acoustic homing torpedoes. “It consists of three components,” continues Mr. Levi: “A defence programmer that analyses threats and selects a pre-programmed response; a launcher controller that enables the selection and firing of torpedo countermeasures; up to 32 launchers for firing up to 32 decoys.”
Rafael has developed integrated submarine anti-torpedo systems: Shade, Scutter and Torbuster.“When an incoming torpedo is detected by a submarine, there are two things the Commander can do: manoeuvring and sending out a counter-measure. These are all human made decisions. We decided to offer systems that can facilitate and improve this decision-making either automatically or semi-automatically,” said Doron Levi, Marketing and Business Development Director for Naval Warfare Systems at Rafael.
The SHADE suite offers multiple decoy options such as the Scutter and Torbuster. The Scutter, which is a soft-kill decoy, is a ‘mini’ torpedo in appearance and has an onboard sonar receiver and library. When launched from a submarine by the SHADE suite against an enemy torpedo, the Scutter uses its library to classify the type of torpedo fired against the submarine. The Scutter then transmits a number of ‘deception’ sonar signals to present alternative targets to the incoming torpedo. According to Rafael, Scutter has the goal of wasting the incoming torpedo’s energy away from the target submarine. Scutter is already in use with the Royal Australian Navy on the ‘Collins’ class, as well as with the US and the Israeli navies.
The Torbuster, like the Scutter, also appears like a mini torpedo. The Torbuster is, however, a hard-kill decoy that targets the incoming torpedo and detonates to destroy it. The decoys used in the SHADE system are stored in small launchers on board the submarine. Rafael claims SHADE can enable carriage of up to 32 decoys.
“However, torpedoes are becoming more and more intelligent and some have a long autonomy, as such it sometimes become inevitable to send another counter-measure that can end the run of the torpedo by disabling its electronics and motors,” says Mr. Levi. Torbuster: Launched from an external launcher, it propels itself at a safe distance from the submarine and seduces the torpedo by transmitting specific acoustic signals. When the torpedo approaches the decoy, at the closest point of approach, it self explodes and neutralises it.
In Feb 2021, it was announced on the side-lines of Aero India, that state-owned Bharat Dynamics Limited (BDL) would team up with Israel’s Rafael Advanced Defense Systems for joint induction of the SHADE ‘anti-torpedo’ defence system for the Indian Navy. And India’s submarine threat environment is growing. Pakistan is scheduled to induct from 2023 the first of eight Chinese-designed diesel-electric submarines. A report of the US Congressional Research Service on China’s naval modernisation, updated in January this year, predicted that by 2025, Beijing could have 55 diesel-electric submarines and 10 nuclear attack submarines in service. The same report estimates China could have over 150 major surface warships capable of anti-submarine operations by 2025. Interestingly, reports in 2019 said Pakistan had purchased an anti-torpedo defence system from Turkey called the Zargana for its submarines. The Zargana relies on jammers and decoys and manoeuvring to evade a torpedo attack.
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