Submarine First: Why Undersea Power Leads India’s Naval Modernisation
If there is one domain where urgency now outweighs symbolism in India’s naval modernisation, it is beneath the surface.
While public debate often gravitates toward aircraft carriers and blue-water task forces, strategic prioritisation inside the system increasingly points to submarines as the more immediate requirement. The logic is straightforward: in an era of long-range surveillance, anti-ship missiles, and expanding Chinese maritime presence in the Indian Ocean Region, stealth and survivability matter more than visibility.
Naval planners are pushing for accelerated submarine induction across both conventional and nuclear categories. Competing priorities include large capital surface ships, but submarine expansion is widely regarded as the more pressing operational necessity.
Budget allocations will determine pace. But sequencing now appears to favour the undersea fleet.
The Current Fleet Reality
India’s conventional submarine fleet has faced gradual depletion over the past two decades due to retirements outpacing induction. The six boats under Project 75 — the Kalvari-class — represent a major modernization step, but they do not fully offset the numerical gap.
The Kalvari-class, based on the Scorpène design, has improved stealth and modern combat systems. However, naval planners have consistently signaled that overall submarine strength remains below desired levels, especially when viewed against expanding regional underwater capabilities.
The urgency is shaped not just by numbers but by operational geography. The Indian Ocean Region has witnessed periodic deployments by the People’s Liberation Army Navy, including nuclear-powered submarines. Persistent undersea presence complicates maritime situational awareness and increases deterrence demands.
Project 75I: Delayed but Critical
The follow-on program, commonly known as Project 75I, remains under evaluation and negotiation. It is intended to deliver next-generation conventional submarines equipped with advanced air-independent propulsion systems and enhanced endurance.
The project has experienced delays linked to cost, technology transfer conditions, and industrial participation frameworks. Yet within naval circles, 75I is considered indispensable for maintaining credible undersea deterrence.
Unlike surface combatants, submarines do not project presence in a visible way. Their value lies in uncertainty. A deployed submarine complicates adversary planning by introducing risk that cannot be easily neutralised.
In fiscal debates, this survivability factor weighs heavily.
Nuclear-Powered Attack Submarines (SSNs): Strategic Autonomy Underwater
Beyond conventional submarines, India’s longer-term ambitions include expanding its fleet of nuclear-powered attack submarines.
India already operates the ballistic missile submarine INS Arihant, which anchors the sea-based leg of the nuclear triad. However, attack submarines — distinct from ballistic missile submarines — serve a different purpose: escorting carrier groups, shadowing adversary submarines, and conducting deep-sea interdiction.
The SSN program is viewed internally as a long-horizon but strategically transformative capability. Nuclear propulsion allows sustained high-speed underwater operations without surfacing for air, dramatically increasing endurance and operational reach.
In discussions around naval prioritisation, SSNs are frequently cited as more aligned with India’s future maritime contest than a third aircraft carrier.
However, nuclear submarine construction is capital-intensive and technologically demanding. The program’s pace will depend on industrial capacity, reactor production, and sustained funding commitment.
The Carrier Debate in the Shadow of Submarines
The proposal for a third aircraft carrier, associated with INS Vishal, remains under evaluation.
Naval planners argue that a three-carrier structure ensures continuous operational availability across both eastern and western seaboards. Yet within the broader defence establishment, questions persist regarding sequencing.
Competing priorities include submarine expansion, air force recapitalisation, and land-based missile modernization. Given finite resources, trade-offs are unavoidable.
Submarines offer asymmetric leverage. They are harder to detect, cheaper to conceal, and less politically visible than carriers. In an era of anti-ship ballistic missiles and precision targeting, some strategists argue that survivability should outweigh prestige.
The debate is not settled. But in near-term prioritisation, submarines appear to command stronger consensus.
Sea Denial vs Sea Control
At the doctrinal level, the conversation increasingly distinguishes between sea control and sea denial.
Aircraft carriers represent sea control — projecting air power and establishing dominance over maritime zones.
Submarines embody sea denial — preventing adversaries from operating freely by introducing persistent, invisible threat.
Given India’s geographic advantage astride major sea lanes, sea denial strategies hold particular relevance. Even a limited but credible submarine force can impose disproportionate caution on larger fleets operating within range.
This logic underpins the argument that undersea capability offers high strategic return relative to cost.
Industrial and Fiscal Realities
Despite consensus on urgency, execution remains complex.
Submarine construction requires specialised shipyard infrastructure, long build cycles, and sustained funding stability. Delays in procurement approvals ripple across timelines. Technology transfer negotiations influence industrial participation.
Budget allocations will determine pace. Defence spending must accommodate modernization across multiple services, including the Air Force’s fighter induction requirements and the Army’s equipment upgrades.
Naval planners are pushing for predictable multi-year funding commitments to avoid start-stop cycles that inflate costs and delay readiness.
Without fiscal consistency, even well-designed submarine programs risk timeline slippage.
The Strategic Outlook
India’s maritime strategy is evolving toward layered deterrence. Surface combatants, carriers, amphibious platforms, and unmanned systems all contribute to that architecture. But beneath the visible expansion lies a quieter recalibration.
Undersea dominance is increasingly seen as the foundational layer of credible maritime deterrence.
Submarines offer survivability in contested environments. They provide strategic ambiguity. They complicate adversary planning without requiring visible escalation.
The coming decade is likely to reveal a sequencing pattern: conventional submarine reinforcement first, SSN acceleration next, and major surface platform decisions following fiscal clarity.
Ambition remains broad. But arithmetic, geography, and threat assessment suggest that India’s naval future will be shaped first by what operates below the surface.
