Mazagon Dock Shipbuilders Limited (MDL) is positioned to secure two major submarine contracts worth over ₹1.06 lakh crore from the Indian government by the end of financial year 2025-26, marking the largest defence procurement in India's history. These contracts represent a critical investment in India's naval capabilities and underscore the strategic importance of maritime security in the Indo-Pacific region, reported Rahul Singh of Hindustan Times.

Project 75I: The ₹70,000 Crore Advanced Submarine Program: Technical Specifications And Partnership

The centrepiece of this procurement is Project 75I, valued at ₹70,000 crore, which will see MDL partnering with Thyssenkrupp Marine Systems (TKMS) to construct six advanced submarines. These submarines will be based on the HDW Class 214 design, a proven platform that combines the design principles of the Type 209 family with advanced features from the Type 212A boats.

The HDW Class 214 submarines offer impressive specifications, including a length of approximately 72 meters, a pressure hull diameter of 6.3 meters, and a surface displacement of around 2,000 tonnes. These single-hull, one-compartment submarines feature eight weapon tubes and can accommodate a crew of 27 personnel.

Air Independent Propulsion Technology

The distinguishing feature of these submarines is their Air Independent Propulsion (AIP) system, which utilises Siemens polymer electrolyte membrane (PEM) hydrogen fuel cells. This technology allows submarines to remain submerged for approximately two weeks without surfacing or snorkelling, significantly enhancing stealth capabilities and operational effectiveness. The AIP system generates electricity through the chemical reaction of hydrogen and oxygen, producing only water as waste while maintaining extremely quiet operation.

Indigenisation And Technology Transfer

A crucial aspect of Project 75I is its emphasis on indigenous content and technology transfer. The first submarine must have a minimum of 45% indigenisation, with local content increasing to 60% by the sixth submarine. This progressive indigenisation approach aligns with India's Atmanirbhar Bharat initiative and aims to establish domestic submarine manufacturing capabilities.

The technology transfer from tkMS to India will enable future indigenous submarine development, representing a significant advancement over previous technology transfer arrangements. The first submarine is expected to be delivered seven years after contract signing, with subsequent submarines following at an annual delivery rate.

Additional Scorpene-Class Submarines: ₹36,000 Crore Investment: Enhanced Capabilities

The second major contract involves three additional Scorpene-class submarines worth ₹36,000 crore. These submarines will be larger and more advanced than the existing Kalvari-class vessels, featuring certain design changes and incorporating 60% indigenous content. The new submarines will be similar to those supplied to the Brazilian Navy and will be slightly larger than the previous six submarines.

Delivery Timeline

The first of these three new Scorpene-class submarines will be delivered six years after contract signing, with the remaining two following at an annual rate. This timeline ensures continuity in submarine production while maintaining the skilled workforce and established supply chain at MDL.

Strategic Context And Naval Modernisation: Current Fleet Status

The Indian Navy's submarine fleet currently consists of 16 conventional submarines, with the recent commissioning of INS Vaghsheer in January 2025 completing the original Project 75 program. The six Kalvari-class submarines built under Project 75 represent India's current backbone of conventional submarine capability.

Regional Security Dynamics

These submarine acquisitions are driven by evolving regional security dynamics, particularly China's expanding naval presence in the Indian Ocean Region and Pakistan's submarine modernisation efforts. The Chinese PLA Navy operates 355 warships and submarines, making it the world's largest naval force, while Pakistan is developing submarine capabilities with Chinese assistance.

Naval Expansion Goals

India's submarine procurement is part of an ambitious naval expansion program targeting a fleet of 175 ships by 2035. Currently, the Indian Navy operates over 130 vessels, with 61 warships and submarines at various stages of construction and an additional 17 warships and nine submarines awaiting approval.

Technology Integration and Upgrades: DRDO AIP System Integration

In a parallel development, the Defence Research and Development Organisation (DRDO) has been developing an indigenous AIP system for the existing Kalvari-class submarines. In December 2024, the government signed a ₹1,990 crore contract with MDL for constructing and integrating AIP plugs for the DRDO-AIP system. The first indigenous AIP system is expected to be retrofitted onto INS Kalvari during its major refit in September 2025.

Electronic Heavy Weight Torpedo Integration

Simultaneously, a ₹877 crore contract was signed with Naval Group of France for integrating Electronic Heavy Weight Torpedoes (EHWT) onto the Kalvari-class submarines. This integration will significantly enhance the firepower capabilities of the existing submarine fleet.

Industrial Ecosystem Development

The combined submarine programs are expected to generate substantial employment opportunities. The AIP integration project alone will create nearly three lakh man-days of employment. The broader submarine construction programs will sustain thousands of skilled jobs across MDL's facilities and the extensive supplier network.

MDL and its partners have developed a robust industrial ecosystem involving more than 50 Indian companies for submarine construction. This ecosystem includes an Indian subsidiary of Naval Group employing over 70 Indian engineers to support the Indian Navy's submarine programs.

Manufacturing Capabilities

MDL has demonstrated its capability to simultaneously build 11 submarines and 10 destroyers, positioning it as India's premier submarine construction facility. The company's proven track record includes successful delivery of six Scorpene-class submarines under Project 75, with the final submarine, INS Vaghsheer, commissioned in January 2025.

Contract Finalisation

Both submarine contracts are expected to be signed before March 31, 2026, following the completion of commercial and technical negotiations. The Cost Negotiation Committee (CNC) has been established to finalise terms, with discussions already underway for both projects.

Delivery Schedule

The comprehensive delivery timeline spans over a decade:

Project 75I: First submarine delivery seven years post-contract, followed by annual deliveries
Additional Scorpène Boats: First submarine delivery six years post-contract, followed by annual deliveries

This staggered delivery approach ensures continuous submarine induction while maintaining production efficiency.

These submarine acquisitions will significantly enhance India's underwater warfare capabilities, providing advanced platforms for anti-submarine warfare, anti-surface warfare, intelligence gathering, and special operations. The submarines' extended underwater endurance and stealth capabilities will strengthen India's maritime deterrence posture.

The emphasis on technology transfer and indigenisation represents a crucial step toward achieving self-reliance in submarine technology. The progressive increase in indigenous content, from 45% to 60%, demonstrates India's commitment to developing domestic defence manufacturing capabilities.

The addition of nine advanced submarines to India's fleet will help maintain the regional balance of power in the Indian Ocean. These platforms will provide India with enhanced capabilities to monitor sea lanes, protect maritime interests, and respond to emerging security challenges.

The ₹1.06 lakh crore investment in submarine capabilities represents one of India's most significant defence procurements, reflecting the strategic importance of maritime security in the 21st century. Through these contracts, India is not only enhancing its naval capabilities but also building the foundation for a robust domestic submarine manufacturing industry that will serve the nation's defence needs for decades to come.

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