India is pursuing a two-pronged approach to significantly expand and modernize its conventional submarine fleet. The government is currently weighing the acquisition of three additional Scorpene-class submarines, which would extend the existing Kalvari-class production line at Mazagon Dock Limited (MDL) in Mumbai.
Simultaneously, the larger and more ambitious Project-75(I) program, slated for six advanced diesel-electric attack submarines, is moving closer to final approval. Defence Secretary Rajesh Kumar Singh confirmed that both proposals are under consideration, with Project-75(I) being at a more advanced stage.
Project-75(I): A Major Strategic Investment
Project-75(I) represents an estimated investment exceeding ₹80,000 crore. This program envisions constructing six advanced submarines in India through a strategic partnership, with Germany’s Thyssenkrupp Marine Systems (TKMS) being a prominent contender. The initiative is expected to involve substantial participation from Indian private-sector companies, fostering indigenous defense manufacturing.
These new submarines are designed to incorporate cutting-edge features, including advanced sensors, sophisticated weaponry, enhanced stealth capabilities, and critical Air Independent Propulsion (AIP) systems. AIP technology allows conventional submarines to remain submerged for extended periods, significantly boosting their operational endurance and covertness.
Indigenous Upgrades for Existing Fleet
Beyond new acquisitions, the Indian Navy is also committed to upgrading its current submarine fleet. The Defence Research and Development Organisation (DRDO) has successfully developed an indigenous AIP system. This system is slated for installation on one of the Scorpene-class submarines during its mid-life refit, expected around the middle of next year, according to Defence Secretary Singh.
This integration of a domestically developed AIP system will enhance the capabilities of the existing Scorpene fleet, aligning with India's broader goal of self-reliance in defense technology. The modernization efforts extend further with the Naval Physical and Oceanographic Laboratory (NPOL) having developed an indigenous integrated combat system for submarines, which will be progressively installed across the fleet during refits.
Regional Context and Future Outlook
These parallel efforts in new construction and fleet upgrades come as India monitors regional naval developments, including Pakistan's induction of Chinese-designed Hangor-class submarines. The proposed additional Scorpene submarines would leverage an established production line, while Project-75(I) would introduce a distinct class of advanced conventional submarines through international collaboration.
The combination of new submarine construction, the integration of indigenous AIP technology, and advanced combat systems underscores India's multi-faceted strategy to bolster its conventional underwater capabilities and maintain a robust naval presence.