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India's Ministry of Defence has approved the procurement of the country's first diesel-electric submarines that will be fitted with air independent propulsion (AIP).
The six-ship acquisition has an estimated value of approximately Rs 40,000 crore (US$5.57 billion).
However, it has been reported that the first new AIP-equipped submarine is not likely to enter service until the 2030s, compelling the country to rely for the meantime on its existing fleet of 16 submarines plus eight more due to enter service in the near-future.
Germany's ThyssenKrupp Marine Systems, Sweden's Kockums, France's Naval Group, and Russia's Rosoboronexport have expressed interest to participate in the tender to supply India's newest subs.
AIP will enable a diesel-electric submarine to remain submerged for up to 14 days, hence making it difficult to detect.
Conversely, a diesel-electric submarine not fitted with AIP will need to re-surface every 48 hours to charge its batteries, during which it becomes highly vulnerable to detection and attack.