INS Karanj | 06 Feb 2020

Why in News

The third Scorpene submarine, Karanj, will be delivered to the Indian Navy by December 2020.

  • INS Karanj is a part of Project-75 and was launched in January 2018. It is currently in advanced stages of sea trials.

Project-75

  • It is a programme by the Indian Navy that entails building six Scorpene-Class attack submarines.
  • The programme has been undertaken with transfer of technology from French company Naval Group (formerly known as DCNS) at the Mazagon Dock Limited (MDL).
  • The submarines in the P75 Scorpene-Class are powered by the conventional diesel-electric propulsion system.
  • The first Scorpene submarine, Kalvari, was commissioned in 2017 and it would go for a normal refit after six years in 2023, during which time the Air-Independent Propulsion (AIP) would be installed.
  • Second Scorpene Khanderi was inducted in September 2019.
  • The remaining submarines (Vela, Vagir, and Vagsheer) in the series are in advanced stages of manufacturing and trials.

Air-Independent Propulsion

  • Conventional submarines use a diesel-electric engine, and must surface for oxygen required for fuel combustion. If fitted with an Air Independent Propulsion (AIP) system, the submarine needs to take in oxygen less frequently.
  • While many naval powers, including India, have acquired nuclear-powered submarines for deep-sea operations, conventional diesel-electric variants are considered useful for coastal defence. The latter are optimised for stealth, and their weapons and sensors provide for effective operations close to the shore.
  • Diesel-electric submarines require them to come to the surface frequently to charge their batteries, their underwater endurance time is less. ‘Air-independent’ propulsion technology helps to make the diesel generator less dependent on surface air.

Source: TH