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Project 75(I) - Design

Under Project 75I India will purchase 6 next generation diesel submarines with Air Independent Propulsion System (AIP) technology for the Indian Navy by 2022. Conventional diesel-electric submarines have to surface every few days to get oxygen to recharge their batteries. With AIP systems, they can stay submerged for much longer periods. Project 75-I will probably have both vertical launched BrahMos for the sea & land targets and tube-launched torpedoes for anti-submarine warfare.

Acceptance of Necessity for acquisition of six submarines under Project-75(I) was accorded by the Defence Acquisition Council in August 2010. The case is being progressed in accordance with the Defence Procurement Procedure. The Navy issued a Request for Information 07 September 2010 for procurement of 06 conventional submarines under project 75(I). The submarine should be capable of operating in open ocean and littoral / shallow waters in dense asw and ew environment and able to undertake following missions:-

  • anti surface and anti submarine warfare.
  • supporting operations ashore.
  • ISR missions.
  • special force and mining ops.

Prospective collaborators were requested to forward data regarding the following capabilities of the proposed design:-

  • maximum diving depth without limitation on number of dives.
  • maximum operating range (dived-snort-surface) and mission endurance.
  • air independent propulsion system being offered.
  • surface displacement and reserve buoyancy.
  • indiscretion rate.
  • sea water specific gravity operating range.
  • torpedo tubes with capability to launch long range heavy weight wire guided torpedoes, missiles and method for weapon discharge.
  • externally launched torpedo decoy system.
  • integrated combat system (details of prospective suppliers to be provided).
  • contemporary low noise propulsion and power generation system.
  • auxiliary motors with take home capability.
  • contemporary IPMS, SMCS, APMS.
  • AC system customised for operation in tropical waters characterised by high temperature and high humidity conditions.

The following data in respect of the proposed submarine be provided along with response to RFI:-

  • radiated noise levels in frequency band 30 hz to 10000hz (db // ref µpa) at speed of 5 knots and 10 kn
  • noise and vibration data for major propulsion and auxiliary machinery
  • maneuverability & stability characteristics

In 2020 the Indian Navy released a video of capabilities in designing and manufacturing Naval assets. A split second clip showcased a submarine design similar to the present diesel-electric attack Kalvari Class submarine based on the Scorpène-class, but with two important modular sections that are not part of the Kalvari Class design. Often called Super Kalvari, the diesel-electric attack submarines showcased featured the addition of the Fuel Cell-based Air Independent Propulsion (AIP) System module and addition of 8 missiles in each 4-cell Vertical Launch module to house BrahMos SLCM or the Nirbhay Sub-sonic cruise missile. The Kalvari class has an overall length of 66.4m but with the addition of two modules, Super Kalvari will have an estimated overall length of 100m+ that would give it a submerged displacement of over 3000 tons, nearly twice that og the submerged displacement of the Kalvari class submarine. Thwe push to locally develop Lithium-Ion battery system, 5MW Electric Propulsion motor and with successfully trial of the air-independent propulsion (AIP), India is advancing its capabilities to manufacture its own diesel-electric in near future. The S-80 Plus is the only existing 3000 ton displacement submarine design equipped with AIP and is, therefore, closes to the P75(I) requirements, allowing Navantia to comply with minimum modifications, and to focus on making the P75(I) a fully indigenous submarine.

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Page last modified: 06-06-2021 18:15:52 ZULU