The Return of the Hunter: Hangor Class Submarines and Pakistan’s Enhanced Undersea Deterrence

Author: Amina Munir
PNS Hangor, a French-built Daphne-class submarine, commanded by Commander Ahmad Tasnim, fired a homing torpedo into the shallow waters of Diu Head on 9 December 1971. In a few minutes, a 194-man Indian anti-submarine frigate, INS Khukri, was sunk. It was the first submarine to sink a warship anywhere in the world since the Second World War and it caused the Indian Navy to call off Operation Triumph, the intended third missile strike on Karachi, resulting in its entire Western Fleet being sent on an unsuccessful 96-hour search. This undersea war caused a shift in the undersea security calculus of South Asia. Today, the new Hangor class submarine Pakistan Navy is proudly building stands as a direct tribute to that legendary vessel — a generational renewal that will honor its tradition but multiply its strategic weight eight times over.

The Hangor-class submarine is not only milestone only procurement. It is reflected today by state-of-the-art Air-Independent Propulsion (AIP) technology, a local production base, and doctrine to suit the realities of the modern Indian Ocean Region (IOR).

Pakistan Navy has never been left behind with its submarine force. This enabled the Navy to gradually develop its subsurface capability since the 1960s of the United States, when it acquired the Tench-class ships, followed by three Daphne-class submarines of France, the Agosta 70 and Agosta 90B programmes, the last of which incorporated MESMA AIP technology.

Such continuity of institutions is important. Pakistan was not beginning afresh when it signed its historic contract with the Chinese Shipbuilding and Offshore International Company Ltd (CSOC) in April 2015, as the Chinese President, Xi Jinping, paid a state visit to Islamabad to purchase eight next-generation submarines. It was a leap generationally on a well-established basis. The largest arms export deal in Chinese military history of the day, the 4-5billion contract was signed to build four submarines at Wuchang Shipbuilding Industry Group, Wuhan and four at Karachi Shipyard and Engineering Works (KS&EW) under a comprehensive Transfer of Technology (ToT) agreement.

The design of the Hangor class is based on the proven Type 039A/B Yuan-class of China, the mainstay of the conventional submarine force of the People’s Liberation Army Navy, and adapted to the Pakistani Navy. The submarines have a hydrodynamically optimised hull, acoustic absorbing coatings, raft-mounted equipment, and modern acoustic management systems, which make them significantly less detectable.

The major strength of the platform is its Air-Independent Propulsion system through a Sterling engine. Compared to traditional diesel-electric submarines that are required to snorkel every few times. AIP submarines can spend three to four weeks in the water without exposing themselves to the air. This significantly minimises the acoustic and thermal emissions and makes the vessel practically invisible to maritime patrol aircraft and surface anti-submarine warfare (ASW) capabilities. Together with a reported seaworthiness of 65 days, top underwater speed of 20 knots, a maximum depth of 300 metres underwater, and six 533mm torpedo tubes that can fire both heavyweight torpedoes and anti-ship cruise missiles, the Hangor class is a qualitative improvement to any submarine Pakistan has ever deployed before.

The ship also carries Optronic Scopes, Electronic Support Measures (ESM), advanced radar and a highly advanced sonar suite that includes a hull-mounted, flank, towed-array, and mine-avoidance systems, providing complete multi-domain situational awareness.

The maritime doctrine of Pakistan is highly defensive: sea denial, not sea control. It aims to elevate the price of aggressive naval operations to a prohibitive one, especially by using the Anti-Access/Area Denial (A2/AD) operations in the Exclusive Economic Zone and beyond. Here, high-tech AIP submarines represent an asymmetry of costs. The strategic rationale was confirmed by the May 2025 tensions, when the sustained submarine patrol of the Arabian Sea, conducted by Pakistan Navy, within an established A2/AD structure, was effective in deterring the Indian naval forces from approaching the maritime perimeter of Pakistan. This no-shoot deterrence operation was only the persuasive value of a realistic underwater strength.

This too caused the entire Royal Navy task force to be in a defensive posture, though no torpedoes actually went off when the Argentine submarine ARA San Luis was present in the 1982 Falklands War. Presence creates paralysis. Having operational Hangor-class boats will place a consistent, realistic threat grid on any enemy who is operating in the North Arabian Sea, and demands the dedication of substantial ASW resources to screen carrier battle group operations, at a tremendous expense to offensive operational liberty. Also, to pure deterrence, the Hangor class is a direct safeguard to the economic lifeline of Pakistan. About 80 percent of oil imports into the country go through the sea routes, and the China-Pakistan Economic Corridor ends at Gwadar, a port, whose strategic position relies solely on the security of the surrounding sea routes. The submarine force presents a plausible warning to any attempt to blockade or interdict these important arteries.

The Strait of Hormuz dynamic state of security also justifies the strategic thought on the sea denial doctrine in Pakistan. The Strait being one of the most crucial maritime chokepoints in the globe with approximately one-fifth of the world oil passing through it, it has of late been the centre of heightening tensions with Iran signalling, increased naval presence, and numerous threats of disruption to flow by increasing regional tensions. These incidents demonstrate one simple fact: even the sense of maritime interdiction in the narrow sea lanes could trigger the disproportional economic and military consequences in the international arena. The concern of Pakistan with sea denial, A2/AD capabilities in such an environment is not only defensive but also the strategic foresight. Like the way Iran has demonstrated the ability to affect the adversarial calculus of the Strait of Hormuz through the use of geography, asymmetric naval platforms, and subsurface platforms, the introduction of AIP-equipped submersibles to the North Arabian Sea would enable Pakistan to be more capable of instilling uncertainty, augmenting operational risk, and discouraging coercive maritime behavior.

The legacy of the Hangor programme, perhaps, is not at sea, but in the Karachi dockyards. The ToT agreement with CSOC is extensive, including submarine design experience, construction methodology of the hull, propulsion system and AIP systems, integration of combat management system, integration of weapons, quality assurance standards and comprehensive training of Pakistani engineers and technicians.

Four out of the eight of the submarines will be built wholly by KS&EW, which is a local industrial success never seen in the history of the Pakistani navy. At full capacity, KS & EW will have the ability to build its own submarines, which will no longer require Pakistan to rely on foreign shipyards to build its most important strategic resources. This is in agreement with the Submarine Vision 2030 of the Pakistan Navy, which predicts a total of no less than eleven AIP-capable submarines by the decade-end, including modernised Agosta-90Bs, which would place Pakistan in the position of being able to deploy one of the most capable conventional submarine forces in Asia.

This was demonstrated in 1971 when one submarine, outnumbered, in shallow water and hunted 96 hours by an entire enemy fleet, outdid size and firepower by stealth, patience and precision. That ship now is exhibited at the Pakistan Maritime Museum. The spirit it had become is resurrected, not once in a shell, but eight times. To the enemies of Pakistan, it represents a threat environment that is exponentially more complicated. To the region it would translate into a more secure and deterrence-based maritime balance. To Pakistan, it signifies that the hunter has come back and this time round, it is in a fleet.

Author is a Research Associate at the Maritime Centre of Excellence, Pakistan Navy War College, and Lahore.