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Last Updated: 02 June 2007

PROJECT 75 - SCORPENE SSK

Vessel Type: Submarine.

Future Commissions: The first of six boats is expected to join the Indian Navy in 2012 and the remaining five will follow at yearly intervals.

Structures & Facilities: The submarine features pressure hull weldable, high tensile, high yield, stress-specific HLES 80 steel and the use of this steel gives the boat an unlimited dive capacity, even at maximum depth. The hull has been designed for silent operations and thus when submerged, the submarine radiates very little noise which in turn improves the performance of its own sonars and also reduces the risk of detection by enemy submarines. The boat features a seven blade, skewed propeller which also assists in radiating low noise.

Due to the optimized hydrodynamic shape of its albacore-shaped hull, the Scorpene SSK enjoys number of benefits such as minimal noise flow in turn keeping the acoustic signature low & causing little interference with the onboard sonar system. The hydro-dynamically efficient hull enables diving to depths in excess of 300 meters and also enabling the propulsion system to sustain a submerged speed of 20 knots for over an hour due to low drag. The boat's main batteries - part of the low noise electrical power plant - will be the main source of power when submerged and powerful diesel generators are used to quickly recharge the batteries once the vessel is at minimum periscope depth. If the MESMA AIP system is used, the submerged endurance is increased by factor of 3 to 4, making it possible for the Scorpene to be underwater for 15 days or more.

The crew amenities, life support systems, safety/diving system are designed for a complement of 30 personnel and patrol time lasting up to two months. High level of automation ensures low demand at the platform management, leaving the crew to focus on navigation and analysis of tactical data on six multifunctional consoles. The boat also features a powerful array of internal & external communication systems. Furthermore, the modular design enables accommodation of two or four diesel generators, a high strength escape trunk-cofferdam, lifeboats or a trailing wire antenna.

Acoustics Discretion: The DCN Press Kit at Euro Naval 2006 states the following about acoustic signature reduction of the Scorpene SSK - quiteness will be achieved by identifying various acoustic situations and the corresponding target level for radiated noise taking into account depth, speed and which items of onboard equipment are in use. Strict requirements are specified for all onboard equipment, the propellers, the hull and hull appendages. Three of the most representative acoustic situations are; (i) patrol at four knots with only essential equipment operating, specifically the auxiliaries required on patrol, (ii) transit at 8 knots to or between patrol areas during which special precautions must be taken to reduce turbulent flow noise and (iii) snorkeling at 6 knots while recharging the batteries. The submarine will be vulnerable to being detected in this situation, primarily due to the noise radiated by the diesel engines. On the other hand, it can also be said that the submarine's diesel generators are sized to ensure that battery charging takes as little time as possible.

The main modes of noise and vibration transmission are also examined very closely. The main sources include mechanical vibration, pressure variations in seawater circuits and shipboard airborne noise. The clean, efficient hull enables it to achieve high submerged speeds with minimal turbulence resulting in both improved sonar performance and reduced risk of detection by the enemy. To further reduce the risk of detection, all vibrating equipment will be isolated from the hull using the same principles adopted for the French Navy's latest nuclear-powered submarines.

Displacement: Submerged; 1790 to 2010 tons.
...................Surfaced; 1550 to 1850 tons.

Dimensions: Length - 66 to 76 meters.
................Draught - Not Known.
................Beam - Not Known.

Diving Depth: 300 to 350 meters (984 to 1150 feet).

Main Machinery: Two diesel generation sets providing a total output of 1250 kW. Also features an elastically supported electronic engine providing 2900 kW of power. The contract with DCN does permit the Indian Navy to fit the MESMA (Module d'energie Sousmarin Autonome) AIP (Air Independent Propulsion) module, after the third boat has been delivered. The Times of India reported on 22 January 2006, that the Indian Navy is indeed looking to install the system on the last three boats. The news article further stated that without the system, the Scorpene can remain underwater for a maximum of four days before surfacing or snorkelling to draw in oxygen needed to recharge its batteries. With AIP, the boat will be able to operate for 18 days, giving it a huge strategic advantage.

Each MESMA system is expected to cost US $50 to 60 million and the Indian Navy will have to acquire permission from the Cabinet Committee on Security (CCS) for the purchase. Vice Admiral Nirmal Kumar Verma, currently Vice Chief of Naval Staff, stated "We are looking very closely at the AIP system and hope to get it in future. The Scorpenes, in any case, are a generation ahead of the Agosta submarines." The only export customer to date for the MESMA system, has been the Pakistan Navy which will use them on their Agosta 90B submarines. If indeed purchased, it would rule out the possibility of the Indian Navy acquiring PEM (Polymer Electrolyte Membrane) fuel cells from Siemens of Germany. Fuel cells are the German variant of an AIP system and are reportedly superior to the French system.

Proponents of the German fuel cells state that they have no moving parts and are thus virtually silent in operation. Its quietness is reportedly unmatched by any other current AIP system in the world. The fuel cells also do not emit exhaust heat, thereby reducing detection. Opponents of fuel cells state that the close proximity of hydrogen and oxygen is inherently dangerous and an explosion of such will result in both boat and crew being lost at sea. Opponents of the French MESMA system state that they are noisier than the German fuel cells because of their moving parts and the disposal of combustion gases, caused by the mixture of liquid oxygen and ethanol. Ultimately it is hoped that the user, regardless of system chosen, makes a final decision based on operational requirements.

Maximum Speed: Submerged; 20 knots.
.......................Surfaced; Not Known.

Maximum Range: Submerged; Not Known.
.......................Surfaced; Not Known.

Maximum Endurance: 45 to 50 days.

Complement: 31 personnel.

Sonar Suite: It's not known for sure whether the TSM 2233 Mk2 sonar or the S-Cube sonar suite will equip the Indian Navy boats. Similar submarines (i.e. Scorpene SSK) built for the Chilean & Malaysian Navies have a COTS (Commercial Off The Shelf) based TSM 2233 Mk2 sonar suite. Scorpenes of the Chilean Navy feature a sonar suite that includes a bow array, distributed array, planar flank array and an active array. Scorpenes of the Malaysian Navy feature a sonar suite that features a basic TSM 2233 Mk2 sonar with some enhancements and also includes mine avoidance sonar. The S-Cube sonar suite is the latest generation of export submarine sonar systems from Thales and is truly an open system architecture & COTS-based TSM 2233 evolution. It's pedigree lies in the core capabilities of the SSN sonar from the French and Royal Navies. Fast adaptive beam forming techniques, large PVDF planar flank arrays and very user-friendly look & feel HMI (Human Machine Interface) combo results in outstanding performance of the multi-mission sonar suite. It achieves panoramic detection, tracking, classification & localization through conventional & adaptive beam forming using a passive cylindrical array, a passive planar flank array, an intercept array, passive ranging arrays and a self noise monitoring system.

Weapons Control: The combat management system onboard the submarine will be a second-generation SUBTICS [Submarine Tactical Integrated Combat System] platform from Underwater Defence Systems International (more commonly known as UDS International) of France. It offers greater situational awareness & operator control through an optimal mix of automated decision making & interactive tools and features a weapon control system, a command & tactical data handling system, an assortment of sonar equipment and an integrated navigation system. Situational awareness will be achieved by fusing data from acoustic (sonar) and non-acoustic sensors (optical, optronic, ESM, radar, communication, navigation & tactical datalinks) while the operator is provided with best control over combat data by employing the latest innovation in multimedia technologies. Also, it features a tailorable HMI based on an 'operational roles & tasks' concept that increases operator efficiency. Extensive use of COTS hardware & software ensures high availability & easy maintenance. Its modular and flexible architecture ensures high adaptability to meet a wide range of operational needs and makes it easier to be upgraded as needs evolve. SUBTICS provides a complete tactical overview of the submarine's surrounding environment. With an ability to download data from external sources, it will allow the submarine to exchange & study tactical data received from other friendly submarines, surface combatants and/or ASW (anti-submarine warfare) helicopters.

Weapons: The submarines will be fitted with six bow-located 21" torpedo tubes, providing a salvo launch capability. The torpedo of choice will be the Black Shark heavyweight torpedo from Whitehead Alenia Sistemi Subacquei (WASS) of Italy. The Black Shark is a dual purpose, wire-guided torpedo which is fitted with an active/passive acoustic head and a multi-target guidance & control unit incorporating a counter-countermeasures system. It has an electrical propulsion system based on a silver oxide and aluminum battery. The boats will also be armed with the Block 2 variant of the Exocet SM-39 AShM which has a range of 50 km and can be launched from under the sea.

Countermeasures: The submarines will be fitted with the C303 anti-torpedo countermeasures system from WASS of Italy. The boats will also feature the AR-900 electronic support measures/direction-finding (ESM/DF) system from EDO Reconnaissance Systems of the US. Additional information on the system can be read from the company's product brochure.

Comments: Project 75 is one of the Indian Navy's standard submarines for the 21st century and is part of the 30 year sub-building program which calls for a projected force of 24 boats of the SSK type. This program is not to be confused with the nuclear powered Advanced Technology Vessel. The second phase of this three decade sub-building program involves Project 76. With a confirmed order of six Scorpene SSKs plus a projected 6 - 8 Project 76 boats, the remaining 12 to 10 submarines are planned to be based on an indigenous design and will marry the best of what the Scorpene and Project 76 boats have to offer.

In February 2001, the then incumbent Chief of Naval Staff - Admiral Sushil Kumar - commented on Project 75 by stating, "Our emphasis will be on re-configuration to build more silent and hunter-killer submarines equipped with long-range weapons and advanced electronic warfare systems." He also stated that the work on upgrading the submarine building facilities at Mazagon Dock Limited in Mumbai had commenced, as the facility had been lying idle after the construction of two Shishumar Class submarines in the early 1990s. Admiral Kumar had previously stated that Project 75 would be a locally re-designed variant of the Shishumar Class, with a tube-launched missile capability. In fact, the first two boats were reportedly designated as the Modified Shishumar Class and were given pennant numbers of S48 and S49 respectively. However Captain S V Nair (Retd.) - former Chairman and Managing Director of Mazagon Dock Limited - in an interview to Business India in July-August 2000, stated that the program was on hold as the designs were still being debated.

German Defence Minister Rudolf Scharping visited India in late February 2001, and held wide ranging discussions from strategy to hardware and is likely that he was indirectly selling the HDW kit for the Project 75 submarine. This suggests that the Project 75 program was likely based on the Shishumar Class submarine, before the Indian Navy decided to move on to more advanced platforms. This theory gained more credence in June 2001, in an interesting twist of events, when the Ministry of Defence gave its stamp of approval for acquiring the Scorpene SSK from DCNS of France. After a few years of protracted negotiations and rising costs, the Indian Government signed a contract in New Delhi on 06 October 2005 for six boats worth US $3.5 billion. All six vessels will be built at Mazagon Dock Limited in Mumbai, with the first boat expected to commission in 2012 and thereafter at the rate of one every year till 2017. However, a spokesperson for DCNS stated in a press release, dated 12 September 2005, that the project could take 15 years to complete which would be around 2020/21.