India’s Defence Research and Development Organisation (DRDO) has signed an agreement with Naval Group to upgrade the country’s Kalvari-class submarines.

As part of the deal, the French defense firm will integrate a domestically-built air-independent propulsion system into the service’s “INS Kalvari” submarine.

The system will improve the performance and lethality of diesel-electric underwater vessels and increase their submerged endurance several-fold.

“It has merits in performance compared to other technologies and is unique as the hydrogen is generated onboard,” Naval Group said in a statement.

The company stated that the propulsion system has reached maturity, confirming its readiness to take on various underwater missions.

Investments in Underwater Capabilities

The decision to upgrade India’s Kalvari-class submarines is one of the country’s ongoing investments in boosting its underwater domain capabilities.

Earlier this week, the Indian Navy commissioned its fifth Kalvari-class submarine, “INS Vagir.”

According to Chief of the Naval Staff, Adm R Hari Kumar, the new submarine will significantly boost the navy’s operational might.

“Vagir is the third submarine inducted into the Navy in a short span of 24 months. This underscores the coming of age of India’s shipbuilding industry, and the maturing of our defense ecosystem,” he said.

The diesel-electric attack submarine has a length of 67.5 meters (221 feet) and can deploy SUT heavyweight torpedoes or SM.39 Exocet anti-ship missiles.

It can remain underwater for 50 days and cover a range of 6,500 nautical miles.