India’s ₹80,000-crore submarine push: Project-75(I) nears final approval

India’s long-pending Project-75(I) submarine programme has moved closer to a final decision, with the government considering a deal worth more than ₹80,000 crore for six advanced conventional submarines to be built domestically with German technology partnership.

Defence Secretary Rajesh Kumar Singh said Project-75(I) is at the final stage and has been submitted for a decision by the competent authority. The programme is expected to involve Mazagon Dock Limited (MDL) and German defence company Thyssenkrupp Marine Systems (TKMS), with substantial participation from Indian private-sector firms.

Project-75(I) envisages six diesel-electric attack submarines equipped with advanced sensors, weapons, stealth features and Air Independent Propulsion (AIP). The programme is being pursued under India’s Strategic Partnership model, which seeks to combine foreign defence technology with domestic manufacturing.

The submarines are expected to be built in India rather than imported as complete platforms. This is intended to expand domestic shipbuilding capabilities and increase Indian industry’s participation in complex defence manufacturing.

The programme has been in the pipeline for years as the Indian Navy seeks to modernise its conventional submarine fleet. Its proposed technology package includes enhanced underwater endurance, improved stealth and modern combat systems.

German partnership at the centre

The proposed partnership with TKMS is a key component of Project-75(I). The German company is expected to work with an Indian shipyard under the strategic partnership framework, with MDL identified as the Indian partner in the programme.

The domestic construction model is also expected to involve Indian private-sector companies, broadening participation in submarine production beyond traditional defence shipbuilding arrangements.

 

Singh said the submarines under Project-75(I) will be built entirely in India. The final approval will determine when the programme can move from the contracting stage towards construction.

AIP and indigenous systems add to modernisation

The submarine programme is being accompanied by efforts to upgrade India’s existing underwater fleet. The Defence Research and Development Organisation (DRDO) has developed an indigenous AIP system, which the Navy is seeking to install on a Scorpene-class submarine during a planned mid-life refit.

AIP allows conventional submarines to remain submerged for longer periods without surfacing, potentially improving endurance and stealth. The Navy is also preparing to introduce an indigenous integrated combat system developed by the Naval Physical and Oceanographic Laboratory (NPOL). According to Singh, the system will be progressively installed in submarines during refits.

Wider fleet expansion under consideration

Alongside Project-75(I), the government is also considering three additional Scorpene submarines for construction at MDL. Singh said the proposal is at an earlier stage than Project-75(I).

Together, the proposed new submarines, additional Scorpene boats and upgrades to existing vessels represent multiple efforts to strengthen India’s conventional underwater capabilities. The immediate focus, however, remains the final decision on Project-75(I), which would set the course for the construction of six advanced submarines in India.