L&T And DRDO sign pact to build AIP modules


According to the business, a contract was signed on Thursday between Larsen & Toubro (L&T) and the Defence Research and Development Organisation (DRDO) for the development of two Air Independent Propulsion (AIP) System Modules for the Indian Navy’s Kalvari Class of submarines.

What is Air Propulsion System?

  • Purpose: AIP systems are created to make it possible for submarines to operate underwater for extended periods without the need to surface or use a snorkel. Decreasing the chance of being discovered, significantly improves their stealth and durability.
  • Power Source: The submarine’s propulsion and onboard systems are independently powered by AIP systems. They differ from traditional diesel-electric submarines in that they do not entirely rely on ambient oxygen.
  • AIP technology kinds: Submarines use Stirling engines, closed-cycle diesel engines, fuel cells, and other AIP technology types. Each technology has particular advantages and disadvantages.
  • Fuel Cells: The electrochemical reaction of hydrogen and oxygen in fuel cells, a common AIP technology, produces energy. Typically, fuel that has been stored on board, like diesel or methane, is used to produce the hydrogen.
  • Benefits: When compared to conventional diesel-electric submarines, AIP systems provide several advantages, including increased underwater endurance, a smaller acoustic profile, lower emissions, and quieter operation.
  • Drawbacks: Compared to conventional propulsion systems, AIP systems frequently have higher levels of complexity, expense, and weight. They also need specialised maintenance facilities and infrastructure.
  • Operational Capabilities: Depending on the specific AIP technology and the size of the submarine, AIP-equipped submarines can stay underwater for weeks or even months. As a result, missions can be prolonged, patrols can last longer, and operational flexibility is improved.
  • Limitations: Although AIP increases underwater endurance, submarines equipped with it still need to surface from time to time to recharge or replenish their AIP systems or to convert to alternative power sources like nuclear or diesel engines.
  • Deployment: Several nations, including Germany, Sweden, France, China, Japan, and others, use AIP technology. It is frequently added as an upgrade to current submarines or included in brand-new submarine designs.