Germany's Thyssenkrupp Marine Systems (TKMS) Dolphin-class AIP enabled submarine

The Indian Navy's underwater warfare capabilities are set to receive a monumental boost as Mazagon Dock Shipbuilders Limited (MDL) prepares to finalise two critical submarine construction contracts worth over ₹1.06 lakh crore within the current financial year 2025-26.

These twin projects represent India's most ambitious submarine modernisation initiative and mark a decisive step toward achieving maritime self-reliance in the Indo-Pacific region.

The flagship Project 75-India (P-75I) represents a paradigm shift in India's submarine acquisition strategy, with an estimated cost of ₹70,000 crore for the construction of six advanced conventional submarines.

This project, developed under India's Strategic Partnership model, will see MDL collaborating with Germany's Thyssenkrupp Marine Systems (TKMS) to deliver cutting-edge underwater platforms equipped with Air Independent Propulsion (AIP) technology.

The P-75I submarines will be based on an evolution of the German Type-214 design, specifically customised to meet the Indian Navy's stringent requirements. These submarines will feature enhanced stealth capabilities, longer underwater endurance, and advanced sensor systems that will significantly upgrade India's anti-submarine warfare capabilities. The project stipulates that the first submarine must have a minimum indigenous content of 45%, progressively increasing to 60% for the sixth submarine, aligning with India's "Make in India" initiative.

Project 75 Add-On: Enhanced Scorpene-Class Submarines

The second major contract involves the construction of three additional Scorpene-class submarines under Project 75 (Add-On), estimated at ₹36,000 crore. These submarines will build upon the successful foundation of the existing Kalvari-class submarines, incorporating enhanced capabilities including AIP technology that was absent from the original six Scorpene submarines delivered under Project 75.

The add-on project represents a strategic decision to bridge the capability gap while the more complex P-75I project develops. With commercial negotiations already completed, this project is positioned to commence more rapidly than its larger counterpart.

India's Submarine Fleet Challenges

India's current submarine fleet consists of just 17 submarines, comprising 16 conventional and one nuclear-powered vessel, a force structure that naval strategists consider insufficient to counter emerging threats from Pakistan and China. Many of these submarines are ageing, with some platforms exceeding 25-30 years of service, creating an urgent need for modernisation and replacement.

The Indian Navy's ambitious 30-year submarine plan, approved in 1999, envisioned the construction of 24 submarines by 2030. However, bureaucratic delays, technical challenges, and procurement bottlenecks have significantly hampered progress. The current dual-project approach represents a critical effort to accelerate submarine induction and address the growing capability gap.

Air Independent Propulsion Technology: A Game-Changer

The integration of AIP technology represents a revolutionary advancement for India's submarine capabilities. AIP systems allow conventional submarines to remain submerged for extended periods—up to two weeks compared to the traditional 2-3 days—without the need to surface or snorkel for battery charging. This technology dramatically enhances stealth capabilities and operational flexibility, making submarines virtually undetectable during extended patrol missions.

Germany's TKMS brings proven AIP technology to the P-75I project, with their fuel cell-based systems already operational on Type 214 submarines serving with South Korea, Greece, Portugal, and Turkey. The technology converts chemical energy from hydrogen into electrical power at approximately 70% efficiency, significantly higher than conventional diesel engines.

Pak-China Factor

The urgency behind India's submarine modernisation is underscored by the rapid advancement of regional competitors. Pakistan currently operates three French Agosta-90B submarines equipped with AIP technology, while China has ordered eight additional AIP-equipped Hangor-class submarines from China, bringing their total AIP-capable fleet to 11 submarines by the early 2030s.

China's expanding naval presence in the Indian Ocean, supported by its "String of Pearls" strategy, poses an additional challenge to India's maritime security interests. The People's Liberation Army Navy has rapidly expanded its submarine fleet and extended its operational reach throughout the Indo-Pacific region, necessitating a robust Indian response.

Private Sector Partnership

The P-75I project represents the first major implementation of India's Strategic Partnership model in the submarine sector. This framework, introduced in 2016, aims to revitalise the defence industrial ecosystem by encouraging private sector participation alongside established public sector undertakings. The model emphasises technology transfer, indigenous content development, and the creation of a tiered industrial ecosystem that can support long-term defence manufacturing capabilities.

Under this partnership, TKMS will transfer submarine design and technology to India, enabling the development of indigenous capabilities that can support future submarine programs, including the planned Project 76 for entirely indigenous submarine construction.

Project Execution Schedule

According to MDL officials, the first submarine under P-75I will be delivered seven years after contract signing, with subsequent submarines delivered at the rate of one per year. For the P-75 add-on project, the first enhanced Scorpene submarine will be delivered six years after contract execution, followed by annual deliveries.

If contracts are finalised by March 2026 as projected, the first P-75I submarine could enter service by 2033, while the first enhanced Scorpene could be operational by 2032. This timeline, while ambitious, reflects the complexity of integrating advanced technologies and achieving the required indigenous content levels.

Manufacturing Readiness

MDL's leadership has expressed confidence in the organisation's readiness to execute both projects simultaneously. Commander V Puranik (Retd), Director (Corporate Planning and Personnel) at MDL, emphasised that the shipyard possesses the skilled workforce and established supply chain networks necessary for immediate project commencement.

The completion of the sixth Scorpene submarine, INS Vaghsheer, in January 2025 demonstrates MDL's proven capability in submarine construction and provides a solid foundation for the upcoming projects.

Cost And Budget Implications

The combined project value of over ₹1.06 lakh crore represents a significant financial commitment that far exceeds initial estimates. The P-75I project alone has escalated from an original benchmark of ₹43,000 crore to ₹70,000 crore, raising concerns about cost management and budget allocation.

This cost escalation reflects the complexity of modern submarine systems, the integration of advanced technologies, and the premium associated with technology transfer and indigenous content requirements. The government's Cost Negotiation Committee will play a crucial role in finalising commercially viable terms that balance capability requirements with fiscal responsibility.

Technical And Integration Challenges

The integration of AIP technology into Indian submarines presents both opportunities and challenges. While tkMS brings proven AIP systems, adapting these technologies to Indian Navy specifications and operating conditions requires careful engineering and extensive testing. The requirement for progressive indigenisation adds another layer of complexity, as Indian suppliers must develop capabilities to manufacture sophisticated submarine components.

Historical precedents, including delays in previous submarine projects, underscore the importance of robust project management and risk mitigation strategies. The success of these projects will depend on effective coordination between international partners, domestic suppliers, and naval requirements.

Strengthening India's Maritime Posture

The successful completion of these submarine projects will significantly enhance India's underwater warfare capabilities and maritime security posture. The addition of nine modern submarines equipped with AIP technology will provide the Indian Navy with enhanced surveillance, reconnaissance, and strike capabilities across the Indian Ocean region.

These submarines will be capable of conducting extended patrol missions, monitoring strategic sea lanes, and providing credible deterrence against potential adversaries. The integration of advanced sensor systems and modern weapons platforms will enable multi-mission capabilities including anti-submarine warfare, anti-surface warfare, and intelligence gathering operations.

Conclusion

As India stands at the threshold of finalising these transformative submarine contracts, the nation moves closer to achieving its vision of maritime self-reliance and enhanced naval capabilities. The dual projects represent more than mere weapons acquisitions—they embody India's strategic commitment to developing indigenous defence capabilities while addressing immediate security challenges.

The successful execution of these projects will require sustained political will, effective project management, and continued investment in human resources and infrastructure development. However, the potential benefits—enhanced national security, technological advancement, and industrial capacity building—justify the significant financial and organisational commitments involved.

With regional competitors rapidly advancing their submarine capabilities and the Indo-Pacific emerging as a critical theatre of strategic competition, India's submarine modernisation initiative arrives at a crucial juncture. The finalisation of these contracts within the current financial year will mark a decisive step toward ensuring India's continued relevance as a major maritime power in the 21st century.

Agencies