(DEFENCE SECURITY ASIA) — India’s Project-77 is far more than a submarine construction effort — it is the crystallization of New Delhi’s ambition to command the Indian Ocean through indigenous nuclear technology, stealth warfare, and long-range precision strike capability.

Formerly known as Project-75 Alpha, the programme will deliver a fleet of six nuclear-powered attack submarines (SSNs), each representing the pinnacle of Indian maritime engineering under the Atmanirbhar Bharat initiative.

The Indian Navy envisions these vessels as the cornerstone of a multi-layered deterrence grid — capable of hunting enemy submarines, escorting ballistic-missile carriers, shadowing carrier strike groups, and launching land-attack missions deep into hostile territory.

Approved by the Cabinet Committee on Security (CCS) in October 2024, the initial tranche covers the first two submarines at an estimated cost of $4.7 billion, including new infrastructure at Visakhapatnam’s Ship Building Centre (SBC).

The total cost of the six-boat fleet and supporting facilities is expected to exceed $14 billion, making it the most expensive single defence programme in India’s naval history.

India’s urgency in advancing Project-77 has been amplified by the Chinese Navy’s increasing undersea presence in the Indian Ocean Region (IOR), with at least eight to ten PLAN submarines detected on rotational patrols annually, supported by logistics hubs in Gwadar, Karachi, and Djibouti.

New Delhi’s strategic community views these developments as a direct encirclement under Beijing’s “String of Pearls” doctrine, compelling India to establish a credible counter-deterrence posture that ensures persistent undersea surveillance and rapid response capabilities.

Recent satellite imagery and intelligence inputs indicate that construction of the specialized drydock for nuclear submarine assembly at SBC Visakhapatnam is progressing at an accelerated pace, with modular sections and heavy reactor-shielding equipment already delivered by Larsen & Toubro in early 2025.

India’s Defence Research and Development Organisation (DRDO) and Bhabha Atomic Research Centre (BARC) have also finalized the next-generation Integrated Platform Management System (IPMS) and acoustic isolation mounts, which will significantly reduce radiated noise levels and enhance survivability against PLAN’s advanced Type-093B and forthcoming Type-095 SSNs.

Crucially, Indian naval planners are aligning Project-77’s operational doctrine with the broader Indo-Pacific strategic framework, ensuring interoperability with QUAD partners through intelligence-sharing, anti-submarine warfare (ASW) exercises, and potential deployment coordination with the U.S. Navy’s 7th Fleet and Japan Maritime Self-Defense Force in contested maritime corridors.

STRATEGIC BACKGROUND: FROM ARIHANT TO PROJECT-77

The roots of Project-77 reach back to the 1990s, when the Advanced Technology Vessel (ATV) programme produced the INS Arihant, India’s first indigenously built ballistic-missile submarine (SSBN).

That success proved that Indian scientists and engineers could master nuclear propulsion — a feat previously achieved only by the United States, Russia, France, the United Kingdom, and China.

India’s earlier experience with leased Soviet-era Charlie I-class and later Akula II-class submarines gave the Navy its first taste of nuclear-powered endurance and quiet patrol operations.

However, those vessels were primarily used for training and operational familiarization rather than full-spectrum combat readiness.

With China deploying the Type-093B and developing the Type-095 SSN classes, and with increasing PLAN submarine patrols near the Andaman Sea and African littorals, India’s strategic calculus shifted from coastal defence to oceanic deterrence.

Project-75 Alpha, conceived in the early 2000s, gradually evolved into Project-77 — a new designation symbolizing India’s transition from diesel-electric dependence to nuclear-powered sovereignty.

By 2021, the Indian Navy decided to prioritize this SSN fleet over a third aircraft carrier, recognizing that undersea dominance, rather than surface tonnage, will decide future maritime conflicts.

DEVELOPMENT AND PRODUCTION ECOSYSTEM

The design and development of Project-77 are being spearheaded by the Warship Design Bureau (WDB), the rebranded Directorate of Naval Design, in close collaboration with the Bhabha Atomic Research Centre (BARC) and the Defence Research and Development Organisation (DRDO).

The preliminary design phase was completed in February 2020, followed by detailed hydrodynamic testing at the Naval Physical and Oceanographic Laboratory in Kochi.

Private-sector giant Larsen & Toubro (L&T) will construct the pressure hulls at Hazira, while nuclear reactors will be fabricated and integrated at Kalpakkam, Tamil Nadu.

The degree of indigenization is unprecedented — roughly 95 percent of systems, components, and materials are domestically produced, with limited foreign input for specific reactor shielding and noise-reduction technologies.

Each submarine will measure approximately 110 metres in length, displacing up to 10,000 tons when submerged — almost twice that of the Arihant-class SSBNs, placing them in the same category as the French Suffren-class and the British Astute-class SSNs.

The first two hulls are already under fabrication, with design validation expected by 2029 and reactor integration scheduled for 2031.

If timelines hold, India’s first indigenous SSN will enter operational service by 2036, followed by one new unit every 18 to 24 months, ensuring a continuous production rhythm into the 2050s.

TECHNICAL SPECIFICATIONS AND DESIGN FEATURES

Project-77 introduces a revolutionary hull architecture developed by Mishra Dhatu Nigam Limited (MIDHANI) using advanced HY-130 steel, allowing deeper operational dives and greater resilience under thermal stress in tropical waters.

The hull employs a teardrop geometry with a cylindrical mid-section, optimized for minimal hydrodynamic drag and superior acoustic stealth.

Anechoic rubber tiles and double-hull construction dampen sonar reflections, reducing the acoustic signature to rival late-generation Western submarines.

The estimated maximum dive depth exceeds 500 metres, enabling stealthy operations below the thermocline — a major advantage in the warm, variable layers of the Indian Ocean.

These submarines will incorporate an X-rudder configuration for enhanced maneuverability, while the sail design minimizes radar and wake signatures during periscope-depth operations.

Advanced sensor integration includes DRDO-developed sonar suites with a conformal bow array, flank planar arrays, towed passive arrays, and low-frequency intercept arrays for broad-spectrum acoustic detection.

Optical and electronic surveillance is provided by optronic masts featuring infrared, laser-rangefinding, and high-definition video sensors, replacing traditional periscopes.

Collectively, these features elevate Project-77 to the technological level of the U.S. Virginia-class Block IV and the French Barracuda, both regarded as benchmarks for stealth SSNs.

NUCLEAR PROPULSION SYSTEM

At the heart of each Project-77 submarine lies the 190 MWth Compact Light Water Reactor (CLWR-B2) developed by BARC — a quantum leap from the 83 MW pressurized-water reactors that power the Arihant class.

The CLWR-B2 employs highly enriched uranium (45 percent) fuel and an innovative nuclear-electric propulsion (NEP) system that converts reactor heat into electric power for a turbo-electric drive linked to pump-jet propulsors.

This configuration allows the submarine to cruise at 25 knots in near-silent electric mode, while retaining the ability to exceed 30 knots for high-speed pursuits.

Natural circulation within the reactor core eliminates the need for noisy mechanical pumps at low power levels, significantly reducing acoustic detection risks from adversary ASW forces.

BARC engineers are simultaneously developing a 200 MWe variant for the next generation of S5-class SSBNs, ensuring commonality in nuclear engineering and logistics.

The entire propulsion system, including auxiliary turbines and backup diesels, is designed for 20-year core life, allowing uninterrupted patrol cycles without refueling.

ARMAMENT: STRIKE FROM THE DEPTHS

Project-77’s offensive punch comes from its vertical launch systems (VLS) and torpedo tubes capable of firing an array of indigenous and collaborative missiles.

Key weapons include:

Missile / Torpedo	Type	Range (km)	Speed / Mach	Role
BrahMos SLCM	Supersonic	800	Mach 3	Anti-ship / Land-attack
Nirbhay SLCM	Subsonic	> 1,500	Subsonic	Stealthy deep strikes
BrahMos-II / LRAShM	Hypersonic	1,500–2,000	Mach 5+	Carrier-killer / Strategic strike
Varunastra / Takshak HWT	Heavyweight Torpedo	Varies	Classified	Anti-submarine warfare

Together, these enable a “shoot and disappear” doctrine where a single SSN can deliver dozens of long-range strikes without surfacing.

The submarines are also expected to deploy autonomous underwater vehicles (AUVs) and extra-large unmanned underwater vehicles (XLUUVs) like the JALKAPI-XLUUV, enabling ISR, mine warfare, and electronic deception missions far from the mothership.

This manned-unmanned teaming approach mirrors the U.S. Navy’s Orca programme and indicates India’s entry into the era of hybrid underwater operations.

STRATEGIC SIGNIFICANCE: THE NEW UNDERSEA TRIAD

The deployment of six SSNs under Project-77 will transform India from a regional naval power into a maritime deterrent state capable of sustained undersea presence across the Indo-Pacific.

Unlike the Arihant-class SSBNs, which serve as second-strike platforms, these SSNs are designed for first-response power projection — shadowing adversary fleets, securing sea lines of communication, and enforcing sea denial.

Their unlimited range and endurance mean they can patrol the South China Sea, Strait of Hormuz, and even the Western Pacific, coordinating with friendly navies under the Quadrilateral Security Dialogue (QUAD) framework.

Project-77 also acts as India’s counterbalance to the AUKUS pact, which will deliver nuclear-powered submarines to Australia, potentially shifting the Indo-Pacific balance.

With China expanding its overseas bases from Gwadar (Pakistan) to Djibouti (Horn of Africa) and deploying Type-093B SSNs through the Malacca Strait, India’s nuclear submarines will serve as persistent underwater sentinels ensuring deterrence and rapid escalation control.

Strategically, these submarines extend the reach of India’s nuclear triad, giving policymakers a credible sea-based tactical strike capability beyond its traditional SSBN fleet.

They also provide crucial escort functions for INS Vikrant and future Vikrant-II aircraft carriers, shielding them against Chinese and Pakistani submarine threats.

CHALLENGES AND TECHNOLOGICAL RISKS

Despite the optimism, Project-77 faces significant engineering and financial challenges.

The integration of untested turbo-electric propulsion systems in warm tropical waters poses a major technical hurdle, as thermal efficiency declines under high ambient temperatures.

Reactor miniaturization for compact hull spaces demands advanced metallurgy and precision welding techniques still being refined in Indian shipyards.

Budgetary constraints and the simultaneous funding of S5-class SSBNs could stretch financial allocations, potentially delaying follow-on boats beyond 2040.

Moreover, India’s submarine-building ecosystem currently lacks the production rhythm of Russia’s Sevmash or the U.S. Electric Boat Division, both of which sustain parallel SSN and SSBN assembly lines.

Training nuclear-qualified submarine crews is another long-term challenge — with each boat requiring about 100 specialist personnel, including nuclear engineers, sonar analysts, and weapons officers.

India’s INS Chakra II lease from Russia provided critical experience, but the absence of a current operational SSN means the first Project-77 submarine will also serve as a live training platform.

COMPARATIVE ANALYSIS: GLOBAL CONTEXT

Globally, the U.S. Virginia-class Block V, U.K. Astute-class, French Suffren, and Chinese Type-095 SSNs set the benchmark for nuclear attack submarine performance.

Project-77’s estimated 10,000-ton displacement and 190 MW reactor output position it between the Astute (7,400 tons) and Virginia Block V (10,200 tons), providing India a balanced blend of endurance, speed, and payload.

While it may not yet match the automation levels or reactor quieting of its Western counterparts, its indigenous build gives India the strategic advantage of technology sovereignty — an essential element in nuclear deterrence independence.

Crucially, India’s collaboration with France through the Scorpène programme and discussions on nuclear propulsion expertise exchange under the Indo-French Strategic Partnership could accelerate technological refinement.

In the long term, India’s SSN fleet could evolve into a “Virginia-lite” model — integrating hypersonic weapons, unmanned support drones, and distributed sensor networks across the Indian Ocean.

READ: India Set To Lease K-519 ‘Iribis’: Second Akula-Class Nuclear Submarine To Counter China’s Silent Expansion

THE ROAD AHEAD: 2030–2050

The Indian Navy’s long-range maritime plan, “Maritime Capability Perspective Plan (MCPP) 2037,” envisions a six-boat nuclear SSN fleet complemented by six Arihant/S5 SSBNs and 18 conventional AIP-equipped submarines.

By 2050, India could operate up to 12 SSNs, ensuring two permanently deployed in the Western Indian Ocean, two in the Eastern Indian Ocean, and one or two under maintenance or training cycles.

This posture would allow India to maintain continuous undersea deterrence coverage from the Arabian Sea to the Western Pacific — a feat currently achieved only by the U.S., Russia, and China.

Additionally, the integration of DRDO’s K-series ballistic and cruise missiles will enable cross-platform interoperability, allowing future SSNs to deploy tactical nuclear or conventional payloads as the strategic environment demands.

CONCLUSION

Project-77 is not merely an industrial milestone; it is the strategic backbone of India’s 21st-century naval doctrine.

By merging nuclear propulsion, indigenous production, and precision-strike capability, India is forging an undersea fleet that will secure its maritime frontiers and project power far beyond its littorals.

As the first submarine approaches completion in the mid-2030s, the Indian Ocean will witness a profound shift — one that cements India as a true blue-water power and a guardian of the Indo-Pacific commons.

When fully operational, the Project-77 fleet will stand as a testament to India’s scientific ambition, strategic maturity, and enduring resolve to protect its maritime sovereignty against any adversary, near or far.

Naval analysts believe that once operational, India could maintain continuous deterrence patrols across key maritime choke points, effectively monitoring Chinese and Pakistani naval movements around the clock.

Furthermore, India is exploring the establishment of forward logistics nodes in the Seychelles, Oman, and Indonesia’s Sabang Island, aimed at providing refuelling and resupply options for its nuclear-powered assets, a strategy that mirrors the U.S. Navy’s global undersea support model.

The integration of AI-assisted sonar analytics and autonomous underwater drones under the upcoming National Underwater Domain Awareness (NUDA) Project will enhance threat detection, enabling Project-77 submarines to operate as part of an intelligent, networked maritime grid.

Ultimately, Project-77 represents India’s declaration of technological and strategic parity with established maritime powers, reaffirming its role as the principal security guarantor in the Indian Ocean and a pivotal balancing force in the evolving Indo-Pacific order. — DEFENCE SECURITY ASIA