During the Cold War, the US Navy and the CIA executed one of the most audacious intelligence operations in maritime history — a mission that almost altered the balance of naval power between the two superpowers. This secret venture, known as Operation Ivy Bells, epitomised the extent to which underwater espionage could redefine strategic advantage.
The operation involved tapping into a Soviet underwater military communications cable in the Sea of Okhotsk, a heavily guarded and frigid expanse of the Soviet Far East. For the Americans, this was no ordinary reconnaissance. It was a calculated bid to break into the most secure layer of Soviet naval communications — the invisible lifeline that connected the Soviet Pacific Fleet with its coastal command.
The Action
A specially modified submarine, USS Halibut, equipped with an array of high-tech sonar and diver modules, stealthily infiltrated Soviet waters. Its elite team of divers installed a large, sophisticated wiretapping device around the communication cable on the seabed — capable of recording every signal and transmission that passed through.
For almost a decade, the United States successfully collected vast quantities of unencrypted intelligence on Soviet naval operations, submarine deployments, and missile tests. This trove of information gave the US a near-unmatched strategic edge in understanding Soviet nuclear submarine patrols and weapon readiness.
The covert mission continued undetected until 1981, when it was compromised by a mole inside the National Security Agency (NSA), who leaked details of the operation to the KGB. The leak led to the removal of the tapping device by Soviet divers, ending one of the most successful submarine espionage missions ever conducted.
Underwater warfare, once confined to the secrecy of Cold War espionage, has resurfaced as a defining element of 21st-century maritime power. It is reshaping how nations build deterrence, project strength, and secure influence in the Indo-Pacific
Operation Ivy Bells demonstrated not only how underwater warfare could influence global power dynamics but also how fragile the balance of undersea dominance could be when secrecy failed. Its lessons resonate strongly today, when cables, sensors, and undersea networks form the nervous system of global connectivity and security.
The Underwater Tactics: New Reality
In the modern age, the battlefront has expanded far beyond the visible waters. Underwater operations are no longer limited to passive surveillance or stealth patrols. They are emerging as powerful deterrence mechanisms, with capabilities of both denial and punishment — akin to air and land-based strategic operations.
Three major forces are driving this shift in undersea warfare and shaping the security calculus for nations like India.
First — The China Threat
China is undergoing a rapid and determined expansion of its underwater warfare capabilities. It is developing next-generation nuclear ballistic missile submarines (SSBNs), including the advanced Type 096 class, which will be quieter, stealthier, and more lethal. According to US Department of Defense assessments, China could field as many as 65 submarines by 2025 and up to 80 by 2030, surpassing both the US and Russia in sheer numbers.
Such a formidable fleet will enable Beijing to project power deep into the Indian Ocean Region (IOR), expanding its area-denial envelope and threatening critical sea lanes that sustain global trade — including India’s own energy lifelines from the Gulf.
Second — Maritime Geopolitics
The Indo-Pacific’s maritime balance is undergoing a dramatic transformation. The region remains inadequately equipped to counter China’s underwater surveillance networks, drone submarines, and long-endurance vessels. This imbalance has direct implications for India.
Beijing’s growing presence in the Indian Ocean — from Gwadar and Hambantota to Djibouti — creates a potential subsurface chokehold around the subcontinent. The underwater domain could soon become a tool of coercion, where China leverages its undersea capabilities to negotiate from a position of strength, undermining both Indian and American influence in the IOR.
Nearly 95 per cent of the world’s internet data, financial transactions, and communications travel through undersea fibre-optic cables. A single deliberate disruption could cripple global connectivity, strategic command, and economic stability
Third — Energy and Infrastructure Security
Beyond military operations, the undersea domain is the lifeline of modern civilisation. Nearly 95 per cent of the world’s internet data, financial transactions, and communications travel through a vast network of undersea fibre-optic cables. A single targeted disruption — caused by a Unmanned Underwater Vehicle (UUV), a diver-saboteur, or a stealth submarine — could paralyse financial systems, communication grids, and even military command networks.
The 2022 Nord Stream pipeline sabotage served as a chilling wake-up call, revealing how a deep-sea strike could have profound geopolitical and economic consequences. As global dependency on undersea infrastructure grows, the vulnerability of cables and pipelines will increasingly define national resilience and deterrence strategy.
While Intelligence, Surveillance, and Reconnaissance (ISR) remain key components of undersea warfare, the expanding subsurface dimension demands new doctrines and technologies. Large surface fleets or aircraft carriers may not suffice in countering stealthy, precision-driven threats below the waves.
Serious Situation With Indian Navy
India’s maritime ambitions have grown significantly, but its underwater preparedness lags behind. While the Navy plans to expand its surface fleet to 175–200 ships by 2035, its submarine arm is in a state of serious depletion.
The current fleet comprises ageing Kilo-class (Sindhughosh) and HDW (Shishumar) submarines, while the induction of the Scorpène-class (Kalvari) submarines under Project-75 has been slow. The Navy currently has no operational nuclear-powered attack submarine (SSN) after the decommissioning of INS Chakra-II in 2021.
Nuclear-powered attack submarines form the backbone of underwater strike power. They can hunt enemy submarines, target surface vessels, protect carrier groups, and conduct long-range reconnaissance with unlimited underwater endurance. Their ability to remain submerged for months at a time allows for stealthy, sustained deterrence — a capability India critically lacks.
The long-delayed Project-75(I) — intended to build six advanced conventional submarines with Air Independent Propulsion (AIP) for longer underwater endurance — remains entangled in bureaucratic and procedural delays. Originally conceived in 1997, it has taken over two decades without tangible progress.
The success of Project-75(I) is vital not just for replenishment but for the modernisation and revival of India’s underwater combat capability. Unless accelerated, India risks falling behind regional adversaries in the subsurface domain, even as its surface fleet continues to expand.
To achieve command of the sea, a nation must possess offensive maritime capability, not merely defensive readiness. India’s naval doctrine must evolve to project power and deterrence beneath the waves, not just above them
Drying Up Mines
Another overlooked but crucial pillar of underwater warfare is mine warfare — a strategy that offers both offensive and defensive leverage. Naval mines, when strategically deployed, can block enemy routes, create choke points, and deter intrusion into vital sea lanes.
Equally critical are mine countermeasure vessels (MCMVs), which detect and neutralise enemy mines. The Indian Navy’s Pondicherry-class minesweepers, however, are ageing rapidly and nearing obsolescence, leaving India vulnerable in this area.
Globally, navies are adopting autonomous underwater mine-hunting systems, networked sonar grids, and remote-operated countermeasure vehicles. India’s limited investment in these areas risks constraining its ability to secure key approaches, including the Arabian Sea, Bay of Bengal, and Andaman waters.
Mine warfare, though silent and unseen, remains one of the most cost-effective forms of deterrence in naval strategy — one that India can ill afford to neglect.
Threat is Real
The threat of underwater warfare is no longer speculative. It is immediate, evolving, and intensifying. The Indian Navy’s top brass recognises this reality. Recently, Vice Admiral K. Swaminathan, Commander-in-Chief of the Western Naval Command, warned that “China is becoming more assertive not only in the South China Sea but also in the Indian Ocean Region.” His statement underlines that the next great contest for maritime dominance will unfold beneath the waves.
While India continues to pursue indigenous innovation and modernisation, its naval doctrine still emphasises surface operations and conventional power projection. The rapidly changing nature of warfare demands a shift towards covert, offensive, and grey-zone operations that impose deterrence through denial and punishment.
China’s “Near Seas Defence and Far Seas Protection” strategy offers a model of layered assertiveness — combining coastal security with distant deterrence. India must evolve its own version of this doctrine, prioritising underwater endurance, multi-domain integration, and persistent presence.
India’s future naval dominance will depend not on the size of its surface fleet but on the strength, sophistication, and stealth of its underwater arm. Building credible subsurface capabilities will determine how India shapes the strategic balance in the Indo-Pacific
To achieve command of the sea, as the legendary naval strategist Alfred Thayer Mahan asserted, a nation must possess offensive maritime capability — not merely defensive readiness. For India, this means developing nuclear submarines, unmanned underwater platforms, and an active mine warfare wing, supported by robust ISR infrastructure.
Bottom Line
As the Indian Navy awaits its next moment to assert its maritime might — perhaps reminiscent of 1971’s decisive operations — it must prepare for an altogether different kind of battle: the silent, invisible, and relentless war beneath the sea.
India’s future naval dominance will depend not on the size of its surface fleet but on the strength, sophistication, and stealth of its underwater arm. Building this capacity will send a powerful message across the Indo-Pacific — that India is ready to defend its maritime sovereignty across every dimension, from the surface to the oceanic depths.
The writer is a national security analyst specialising in intelligence and strategic affairs. He has worked extensively with national security and foreign policy think tanks of repute, and has written for publications including The Telegraph, The Print, Organiser, and Fair Observer. He has also been a guest contributor to the School of International Studies at Jawaharlal Nehru University (JNU).
