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AIP (Air-Independent Propulsion) Technology

AIP (Air-Independent Propulsion) Technology:

France’s Naval Group declined the bid for the P-75I Project, citing it does not use AIP (Air-Independent Propulsion) Technology yet.

  • Around 10 countries have developed or are close to building AIP technology, and almost 20 nations have AIP submarines.

P-75I project:

  • In June 1999, the Cabinet Committee on Security approved a 30-year plan for the Navy to indigenously build and induct 24 submarines by 2030.
  • In the first phase, two lines of production were to be established — the first, P-75; the second, P-75I. Each line was to produce six submarines.
  • While the six P-75 submarines are diesel-electric, they can be fitted with AIP technology later in their lives.
  • This P-75I project envisages indigenous construction of submarines equipped with the state-of-the-art Air Independent Propulsion system at an estimated cost of Rs. 43,000 crore.


  • AIP is a technology for conventional non-nuclear submarines.
  • Submarines are essentially of two types: conventional and nuclear.
  • The conventional submarines use diesel-electric engines, which require them to surface almost daily to get atmospheric oxygen for fuel combustion.
  • If fitted with an AIP system, the submarine will need to take in oxygen only once a week.
  • The indigenously developed AIP, which is one of the key missions of the Naval Materials Research Laboratory (NMRL – DRDO), is considered one of the ambitious projects of the DRDO (Defence Research and Development Organisation) for the Navy.