Excelente artigo sobre os torpedos atuais...
The heavyweight contenders: torpedoes maintain their potency
Despite an apparent lack of demand - a heavyweight torpedo has not been fired in anger for more than 25 years - the weapon retains its title as a submarine's main hard-kill weapon
Joris Janssen Lok, Jane’s International Defence Review, March 2006
On 2 May 1982, off the Falkland Islands, the UK Royal Navy nuclear-powered submarine HMS Conqueror sank the Argentine Navy cruiser ARA General Belgrano with two Mark VIII heavyweight torpedoes. In the same month, the Argentine diesel-electric submarine ARA San Luis unsuccessfully fired several torpedoes at British ships that were involved in the operation to recapture the Argentine-claimed island group.
The sinking of the Belgrano, now nearly a quarter of a century ago, was the most recent occasion where heavyweight torpedoes have been fired in anger. Virtually all types of non-nuclear weapons have seen widespread use during the many armed conflicts that have occurred since the early-1980s, but one of the most powerful types of conventional weapon has remained dormant.
Despite this apparent lack of demand, and despite the reduced emphasis on anti-submarine warfare (ASW) programmes in many parts of the world, new submarines are still being ordered, in-service boats are still being upgraded, and the heavyweight torpedo still is the main hard-kill weapon for a submarine's self-defence and for its offensive operations (or indeed, that of certain types of fast attack craft) against surface ships and other submarines.
Budgets, however, have been extremely tight since the 1990s as land or air warfare capabilities have often been prioritised to the detriment of undersea defence capabilities. Another concern is that torpedoes have little practical use against the asymmetric threats that are a main concern for 21st Century navies.
What international export market for heavyweight torpedoes there is at the moment appears to be dominated by two main contenders and three slightly less prominent ones. The two most visible competitors are the Atlas Elektronik DM2A4 Seahake from Germany and the WASS Black Shark from Italy. Swedish-based Saab Underwater Systems is offering the Torpedo 2000, US-based Raytheon is offering the Mk 48 Mod 6/7 ADCAP (advanced capabilities), and the US government is offering surplus Mk 48s of older types.
BAE Systems (Atlas Elektronik's current parent company which builds the Spearfish heavyweight torpedo) is understood to be concentrating on developing upgrades for the UK Royal Navy inventory used on nuclear submarines, rather than competing against Atlas in the export market for conventional submarines.
As for the DM2A4, the German defence procurement agency, BWB, is expected to place its first series production contract for Atlas Elektronik DM2A4 heavyweight torpedoes for the German Navy this month (March 2006), the Bremen-based company (part of BAE Systems but in the process of being taken over by a consortium of ThyssenKrupp Marine Systems and EADS) told IDR at the beginning of February.
The long-awaited order, believed to be for around 70 weapons, follows a pre-series of 10 that was delivered three years ago.
The German contract will keep the DM2A4 production line at Atlas Elektronik's naval weapons plant in Wedel, near Hamburg, open for at least another two to three years, company officials say.
In addition, the Spanish Navy on 3 November 2005 ordered a batch of what is believed to be around 40 DM2A4 torpedoes in association with its programme to build four S 80 submarines. Spanish industry will be involved in the production of the torpedoes to a significant extent, Atlas Elektronik says.
Another possible export contract could come from Greece, which would require around 50 weapons. In Greece, the DM2A4 is facing tough competition from the Black Shark torpedo developed by Whitehead Alenia Sistemi Subacquei (WASS). According to Atlas Elektronik, its weapon can be installed without integration issues on the Hellenic Navy's new Type 214 and upgraded Type 209 submarines. This is because on these boats, Atlas Elektronik is also supplying the command, sonar and weapons control systems (ISUS 90).
Development of the DM2A4 started in 1996, and over 100 full-configuration 'wet firings' have been performed with the weapon to date. Prior to the Spanish order, however, Atlas Elektronik had received orders for "less than 100" weapons: the pre-series of 10 for Germany and an undisclosed quantity for Turkey.
The German weapons are to equip the four Type 212A submarines that are currently being introduced into service. In Turkey, the DM2A4 is used to arm that country's latest Type 209 submarines.
"The production line is dimensioned to build between 40-100 torpedoes per year, but the optimum rate is one torpedo per week," says Kai Pelzer, Atlas Elektronik's executive director for naval weapons.
With the immediate future of the DM2A4 production line secure, Atlas Elektronik is reinforcing its drive to win additional export orders against what Pelzer describes as a "very aggressive" marketing offensive by WASS. The Italian company, working in partnership with DCN International of France (DCN produces major components of the Black Shark), is regarded by Atlas Elektronik as "our main competitor" in the export market.
Atlas Elektronik is offering a non-NATO export version of DM2A4, the Seahake Mod 4 with different guidance and control algorithms, to several potential customers around the world.
The DM2A4 is powered by a 300 kW high-frequency permanent magnet electric motor that, according to Atlas, has an efficiency of 90 per cent. Power for the motor and the on-board electronics is provided by modular silver-zinc batteries. The modular torpedo can be configured with one, two, three or four of these batteries, also called energy packages. The highest-performing DM2A4 configuration is the one with four battery stacks, reportedly providing a top speed of over 50 kt (90 km/h) and a range of up to 90 km (although in a typical medium-speed transit/high-speed intercept scenario the range would be around 50 km).
"In a scenario where the weapon is fired head-on against a frigate-type target that is 20 km away, and that immediately changes course by 180º to run away at a speed of 30 kt, the torpedo's performance is such that it will hit the fleeing target within half an hour," German Navy sources claim.
The DM2A4 is fibre-optic wire-guided, the wire used being an Atlas Elektronik-specified, 300 µm thick optical glass fibre produced by a German-based supplier.
The wire currently offers a bandwidth of up to 10 Mbs, an Atlas engineer said.
The conformal array in the nose of the weapon operates in 40 pre-formed beams and has a field-of-view of "better than ±110º", Pelzer claims.
As said, Finmeccanica-owned company WASS is engaged in a fierce technical and commercial rivalry - a so-called 'torpedo vendetta' - with Atlas Elektronik in the international heavyweight torpedo market, with the former aggressively marketing its new Black Shark weapon.
Development of Black Shark began in 1997 to meet the Italian Navy's requirement for a new-generation heavyweight torpedo for its new U212A-class submarines. Originally known as the A184 Advanced - indicating its provenance in the earlier A184 Mod 3 heavyweight torpedo - the weapon was renamed to reflect WASS' assertion that its capabilities were significantly superior to the legacy A184 line. DCN St Tropez, as partner to WASS, is taking responsibility for the development of the Black Shark's battery system and electric motor.
Black Shark incorporates a new Advanced Sonar Transmitting and Receiving Architecture (ASTRA) active/passive acoustic homing head; an updated guidance-and-control section; a fibre-optic guidance link and spool; a new electric motor; and a skewed contra-rotating propeller. ASTRA, originally developed under a separate national programme, is a multibeam steerable planar array with digital pulse compression in any transmission mode, multifrequency operations in both active (frequency modulation and continuous wave) and passive modes, and independent processing of each frequency (active and passive) on each lobe.
ASTRA operates at 15 kHz (passive medium frequency only) and 30 kHz (active and passive high frequency). The seeker can operate simultaneously in both frequencies in passive mode, allowing the torpedo to discriminate between signals from a real target and signals from an acoustic countermeasure decoy. A fibre-optic link has been introduced in place of a conventional wire-guidance link. This carries sensor data and command and guidance signals to and from the submarine, allowing the torpedo to operate as a forward-deployed sensor for the submarine. Use of optical fibre allows a higher data exchange rate between the submarine and its weapon, offering a nominal 100 per cent increase in guidance range.
Propulsion is provided by a brushless axial flux motor powered by a new AlAgO battery fitted with an electrolyte management system (a low-cost rechargeable lithium ion battery is being developed for exercise use).
The propulsor itself uses contra-rotating 13-blade and 10-blade carbon fibre propellers. Top speed exceeds 52 kt.
Black Shark has entered low-rate production prior to final completion of acceptance testing. A first operational launch was undertaken in November 2004 from O'Higgins, the first of two Scorpene submarines being acquired by the Chilean Navy. The trial, forming part of the submarine's acceptance programme, was carried out by DCN International in international waters along the French-Spanish coastline.
Chile also plans to outload Black Shark to its two Type 209/1300 submarines, Thompson and Simpson. Both boats are to receive a command and weapon-control system update from UDS International, which will offer commonality with the Scorpenes and enable them to operate Black Shark alongside the existing SUT weapon.
Italy will outload Black Shark on to its new U212A submarines, Salvatore Todaro and Sciré. It will also equip the existing submarines of the Sauro class, which are currently armed with the A184 Mod 3 heavyweight torpedo.
As well as being sold to Chile, Black Shark has also secured a berth aboard the two new Scorpene submarines being purchased by Malaysia from Armaris, and on the two Type 209/1500PN boats ordered by Portugal from Howaldtswerke-Deutsche Werft (part of ThyssenKrupp Marine Systems).
The US Navy (USN), through the Naval Undersea Warfare Center (NUWC), Portsmouth, Rhode Island, and Raytheon Integrated Defense Systems are continuing to evolve the Mk 48 ADCAP (Advanced Capability) heavyweight torpedo through a series of 'spiral' hardware and software developments. Evolved from the earlier Mk 48 Mod 4 weapon, the original Mod 5 ADCAP entered service in the late 1980s and introduced digital sonar, signal processing, guidance and control while retaining the proven dynamics and Otto Fuel II propulsion of the original Mk 48 weapon.
Improvements embodied in the current Mod 6 baseline are designed to provide enhanced search and homing, propulsion system quietening, increased reliability, reduced costs of ownership and ease of future technology insertion.
Mod 6 had earlier seen the introduction of an open-architecture guidance-and-control section based on commercial off-the-shelf (COTS) signal- and data-processing hardware and an industry-standard Ethernet databus.
Continuing research, development, test and evaluation activities are focusing on weapon performance improvements in two principal areas, namely Advanced Processor Builds (APBs) and the introduction of the Common Broadband Advanced Sonar System (CBASS). The latter underpins the new Mod 7 variant, which is being co-developed with Australia under a 10-year Armaments Cooperative Project (ACP) agreement signed in March 2003 (Australia is procuring the Mk 48 Mod 7 for its six Collins-class submarines).
Another upgrade planned for the Mk 48 ADCAP is the replacement of the current guidance wire with a fibre-optic cable. Resource constraints have pushed back the introduction of a fibre-optic capability to the end of this decade.
ADCAP user community
Australia, Canada and the Netherlands all currently operate the older Mk 48 Mod 4 heavyweight.
With Australia now committed to purchasing the Mk 48 ADCAP at Mod 7 standard, the USN is actively courting other NATO and allied navies with a view to expanding the ADCAP user community.
BAE Systems Underwater Systems at Waterlooville, southern England, handed over the last Spearfish wire-guided heavyweight torpedo to the UK Ministry of Defence (MoD) in November 2003.
With the last remaining stocks of Mk 24 Mod 2 Tigerfish torpedoes having been retired in February 2004, Spearfish is now the standard weapon outload aboard all UK Royal Navy (RN) nuclear-attack and ballistic-missile submarines.
Spearfish was originally developed to counter the Cold War threat posed by fast, deep-diving Soviet nuclear-attack submarines, with first deliveries to the RN starting in 1988. Powered by a Sundstrand 21TP01 gas turbine (using HAP-Otto bi-propellant fuel) driving a shrouded pump-jet propulsor, Spearfish has a high sprint speed (attaining more than 65 kt during trials), a deep-diving capability and high endurance.
Spearfish's homing system hosts around 200,000 lines of operational code and is capable of both wire-guided and autonomous attacks. Spearfish provides RN submarines with a dual ASW/ASuW (anti-surface vessel warfare) capability. During a US/UK High Seas Firing in the Atlantic in June 2002, a Spearfish torpedo was fired from HMS Tireless at a range of 3.2 km against a stopped target in the shape of the decommissioned cruiser ex-USS Wainwright.
The MoD is now considering options for a follow-on Submarine Launched Underwater Weapon (SLUW) to succeed Spearfish in RN service from the middle of the next decade.
BAE Systems Underwater Systems has already undertaken concept studies, under the banner of the Advanced Spearfish Programme (ASP), to examine improvements to Spearfish and establish the basis for SLUW.
ASP is intended to substantially improve the weapon's performance against quiet targets in shallow-water environments.
The wire-guided Saab Underwater Systems Torpedo 2000 (designated Tp62 in Swedish service) began development in 1988. It uses a bi-propellant propulsion system (a combination of 85 per cent HTP and 15 per cent kerosene). Torpedo 2000 can trade off speed against range up to a maximum of about 50 kt and 50,000 m respectively.
Despite high hopes, Torpedo 2000 has not fared well in the export market and its only international sale to date, a SEK500 million (USD64.5 million) order placed by the Brazilian Navy in 1999, was annulled in 2004. Brazil had intended that Torpedo 2000 would arm its new improved Tupi-class submarine Tikuna. However, the contract was terminated in 2004 for what Saab Underwater Systems says is "mainly a consequence of integration difficulties due to third-party proprietary rights".
The company acknowledges that costs arising from the cancellation could affect the Saab group's overall figures by up to SEK160 million.
Under contract to FMV, Saab Underwater Systems has developed the AUV 62F experimental UUV (unmanned underwater vehicle) based on modules from Tp 62.
![8-]](./images/smilies/icon_cool.gif "Cool"){kind=icon}
