The Export Edition: Why Pakistan’s Hangor Isn’t Beijing’s Real Yuan

New Delhi: Pakistan’s much-hyped Hangor-class submarine programme has been repeatedly showcased as a technological leap in its naval modernisation drive, especially amid ongoing regional tensions in the Indian Ocean. But beneath the fanfare lies a crucial detail: the Hangor is not the same as the People’s Liberation Army Navy’s (PLAN) frontline Yuan-class submarine. 

Instead, it is an export derivative, the S26 design, that likely lacks several high-end features that make the Yuan a formidable asset in China’s undersea arsenal. This distinction underscores Beijing’s strategic caution in arms exports, even to close allies like Islamabad, while highlighting Pakistan’s growing dependency on Chinese technology amid delivery setbacks and the uncertainties of real-world deployment.

The Hangor-class submarines, part of a $5 billion deal signed in 2015, are based on the S26 design, an export-optimised derivative of the Type-039A/B Yuan-class. Four are being built at China’s Wuchang Shipyard in Wuhan, and four at Karachi Shipyard & Engineering Works (KSEW) through technology transfer, aiming to bolster Pakistan’s underwater capabilities in the Arabian Sea.

The Yuan is the PLAN’s primary conventional submarine, combining diesel-electric propulsion with an advanced Air-Independent Propulsion (AIP) system. Deployed extensively in the East and South China Seas, it provides China with a stealthy, persistent undersea presence. With over 20 units in service and more under production, the Yuan incorporates lessons from operational patrols and joint exercises, such as those with Russia in 2025.

However, the S26 variant for Pakistan is likely stripped of sensitive technologies, mirroring Beijing’s pattern of reserving cutting-edge systems for domestic use. While the Hangor benefits from Stirling AIP for extended submerged operations (potentially 2-3 weeks), it relies on the Chinese CHD620 engine, a substitute for German MTU units blocked by export controls, raising concerns about reliability and noise levels compared to PLAN variants. This engine swap, necessitated by geopolitical constraints, underscores the challenges of export models.

Export submarines often differ from their domestic counterparts in three key areas: sensors, combat management systems (CMS), and acoustic quieting. These differences, while subtle, can significantly impact operational effectiveness in high-threat environments like the North Arabian Sea.

The Yuan’s PLAN variants likely carry advanced flank-array and towed-array sonars optimised for long-range detection in contested waters, enhancing situational awareness against quiet adversaries. The S26 is believed to have less capable sensor suites, potentially reducing its ability to detect advanced submarines at range, a critical vulnerability against sophisticated ASW networks. 

Modern submarines rely on CMS to fuse sonar, electronic warfare, and tactical data into actionable targeting solutions. The Yuan integrates advanced Chinese CMS platforms aligned with Beijing’s network-centric warfare doctrine, enabling seamless data sharing with surface fleets and aircraft. Export versions typically feature a downgraded CMS with limited networking capabilities, constraining interoperability. Pakistan’s efforts to integrate indigenous systems may mitigate this, but reliance on Chinese-derived architecture persists, potentially limiting compatibility with non-Chinese assets.

Submarine stealth depends on advanced hull coatings, machinery isolation, and hydrodynamic shaping. The Yuan’s state-of-the-art quieting technologies significantly reduce its noise profile to evade passive sonars. The Hangor, particularly with the unproven CHD620 engine, likely has less advanced acoustic dampening, making it more detectable to Indian Navy ASW assets in the warm, shallow waters of the Indian Ocean, where environmental factors amplify noise propagation.

Pakistan is not alone in facing challenges with Chinese submarine exports, as Thailand and Bangladesh’s experiences reveal systemic issues that amplify concerns about the Hangor programme. Thailand’s 2017 deal for an S26T submarine, a Yuan variant, faced over 1,200 days of delays when Germany blocked MTU396 engine exports, forcing China to substitute the untested CHD620 engine. The Royal Thai Navy’s insistence on rigorous testing halted construction at over 50% completion, nearly scuttling the $430 million project, which was only revived in August 2025 after Thailand accepted the Chinese engine. This mirrors Pakistan’s own engine switch, raising fears of compromised stealth or reliability.

Bangladesh’s 2016 purchase of two refurbished Type 035G (Ming-class) submarines, a Yuan predecessor, for $203 million, further illustrates China’s export strategy. These noisy, outdated boats require heavy Chinese technical support, limiting operational autonomy, while a $1.2 billion Chinese-built submarine base ties Dhaka to Beijing’s logistics. Pakistan’s broader experience with Chinese systems, like the F-22P frigates plagued by radar and missile issues, suggests similar risks for the Hangor’s long-term viability. These precedents highlight the challenges of integrating and maintaining Chinese export platforms. 

The Hangor’s touted endurance, AIP capabilities, and potential Babur-3 submarine-launched cruise missile integration await validation through sea trials. Submarine programmes are complex, and integration issues can undermine paper specifications. Delivery delays have already hit: only three of the planned eight submarines have been launched by August 2025, with none fully commissioned due to ongoing outfitting, trials, and crew training. KSEW’s units face further setbacks from Pakistan’s economic constraints and foreign exchange shortages, pushing full operationalisation to the late 2020s or beyond. The PLAN’s Yuan achieves weeks of submerged operations, but the Hangor’s performance in the Arabian Sea’s challenging conditions remains unproven, necessitating a cautious “watch and wait” approach.

China limits exports to preserve its technological edge, ensuring sensitive systems don’t leak to third parties, even allies like Pakistan. The Hangor ties Pakistan’s navy to Chinese logistics, training, and doctrine, fostering long-term dependency. With 81% of Pakistan’s arms imports from China, including tanks, jets, and now submarines, Islamabad’s naval posture is increasingly beholden to Beijing’s supply chains and geopolitical priorities. Past export issues, like delayed spare parts for Chinese systems, could exacerbate this reliance, limiting Pakistan’s strategic autonomy. For Pakistan, the Hangor offers a generational leap over its ageing Agosta-90B and Agosta-70 boats, with longer endurance, modern systems, and anti-ship missile capabilities. Yet, its effectiveness hinges on overcoming integration and reliability hurdles seen in other Chinese exports.

From India’s perspective, the Hangor heightens the undersea threat in the Indian Ocean, where New Delhi maintains strategic dominance. However, its export limitations and Pakistan’s operational challenges temper its impact. India’s Scorpène-class Kalvari submarines, with French quieting technologies, and its expanding P-8I aircraft and MH-60R helicopter fleets provide exploitable advantages in detection and tracking.  New assets like the INS Arnala and shallow-water crafts further strengthen India’s ASW “kill zone,” ensuring countermeasures against the Hangor’s potential.  While the Hangor warrants vigilance, India’s layered defences maintain a strategic edge.

The Hangor may be sold as Pakistan’s answer to the Yuan, but it remains a derivative of China’s frontline submarine, likely with downgraded sensors, CMS, and quieting. Lessons from Thailand and Bangladesh highlight the risks of delays, unproven components, and dependency, reinforcing the need for vigilance. Post-launch trials will determine if the S26 lives up to its claims, but for now, India’s robust ASW capabilities keep the strategic balance in check, while Pakistan’s reliance on China underscores the challenges ahead.

Commodore (Dr.) Johnson Odakkal is a maritime scholar, strategic affairs analyst, and Indian Navy veteran. He serves as Faculty of Global Politics and Theory of Knowledge at Aditya Birla World Academy, Mumbai, and Adjunct Faculty of Maritime and Strategic Studies at Naval War College, Goa.

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