Pakistan’s naval modernisation is gaining remarkable momentum as its Hangor-class AIP submarines achieve major milestones.

The first boat is undergoing sea trials, the third has already been launched, and the sixth has seen its keel laid. This rapid progression underscores Pakistan’s determination to cement its undersea deterrent with eight new conventional attack submarines by the decade’s end.

Built under collaboration with China Shipbuilding & Offshore International Co. (CSOC), the Hangor-class represents the export variant of China’s Type-039B Yuan-class SSK, featuring Air Independent Propulsion (AIP) for extended underwater endurance.

Four vessels are being built in China, with the remaining four assembled at Karachi Shipyard & Engineering Works (KSEW), reinforcing Pakistan’s industrial capabilities and self-reliance in submarine construction.

Despite adopting a less advanced propulsion setup—based on the CHD620 diesel and a Stirling-type AIP system—the Hangor-class offers Pakistan an edge in persistence and mission flexibility across the Arabian Sea. Although the Stirling AIP is inherently noisier and less efficient compared to modern fuel-cell systems, it still provides multi-day submerged operation, reducing snorkel cycle frequency.

Conversely, the Indian Navy’s Project-75I, which seeks to induct next-generation AIP-enabled submarines with longer underwater endurance and advanced sensor suites, remains stuck at contracting and design finalisation stages. This delay, compounded by the phased upgrade of India’s existing Kalvari-class (Scorpène) fleet, leaves a timing gap in AIP capability through the late 2020s.

By 2030, Pakistan could operationally field up to 11 AIP-equipped boats—including upgraded Agosta-90B submarines fitted with locally developed MESMA-type AIP modules—compared to India’s none, until the P-75I series materialises. This numerical and endurance advantage supports Pakistan’s concept of sustained undersea denial and extends its tactical reach across chokepoints in the North Arabian Sea.

While Indian Kilo- and Scorpène-class submarines maintain qualitative superiority in stealth, sensors, and weapons integration, Pakistan’s quantitative and AIP-based endurance advantage could complicate India’s anti-submarine warfare (ASW) posture in the near term, until indigenous AIP integration or next-gen P-75I boats enter service later in the decade.

Technical Comparison: Hangor-Class Vs Agosta-90B Vs Kalvari-Class Submarines

SpecificationHangor-Class (Type-039B Export)Agosta-90B (Upgraded)Kalvari-Class (Project-75 Scorpène)
Origin/BuilderChina (CSOC) / Pakistan (KSEW)France (DCNS, now Naval Group) / Pakistan (KSEW)France (Naval Group) / India (MDL)
Type/Generation4th Gen Conventional AIP Submarine3rd Gen AIP-Upgraded Submarine4th Gen Conventional Submarine (Non-AIP)
Displacement (Surfaced/Submerged)~2,300 / 2,800 tons~1,760 / 2,000 tons~1,615 / 1,775 tons
Length~76 m~67 m~67.5 m
Propulsion SystemDiesel-electric with Stirling-based AIP (CHD620 diesel engines)Diesel-electric with MESMA AIP (upgraded locally)Diesel-electric (AIP retrofit planned by 2026–27)
Endurance (Submerged with AIP)15–20 days10–14 days8–10 days (post AIP integration)
Maximum Diving Depth~300 m~350 m~350 m
Speed (Submerged)18 knots20 knots20 knots
Crew Complement~38~36~35
Sonar and SensorsH/SQG-207 flank array + Chinese CMSUpgraded Thales DUUX-5 + local CMSSUBTICS sonar suite (integrated French-Indian system)
Torpedo Armament6 × 533 mm tubes (Yu-6 / CM708 torpedoes)4 × 533 mm tubes (ECAN F17 or DM2A4)6 × 533 mm tubes (Whitehead SUT / ECAN F21)
Missile CapabilityCM-708UNB / Babur-3 (SLCM, test-fit)Babur-3 SLCM (limited integration)Exocet SM39 (Anti-ship missile)
AIP TechnologyStirling-cycle AIP (Chinese)MESMA (Closed-cycle steam turbine)Planned PEM Fuel Cell AIP (DRDO-NMRL)
Stealth SignatureModerate (due to AIP mechanical noise)High (older hull design, moderate silencing)Very High (low acoustic signature, advanced silencing)
Build Numbers and Status (2025)8 planned (1 on trials, 3 launched, 6th keel laid)3 in service (all upgraded)6 in service (AIP upgrade planned)
Service Entry Timeline2026–2030 (progressive induction)1999–2008 (modernized by 2022)2017–2024 (AIP retrofit from 2026)
Strategic RoleExtended endurance patrols, second-strike SLCM platformCoastal deterrence, SLCM platformBlue-water ASW and sea control operations

Pakistan’s Hangor-class fleet, combining quantity and AIP endurance, is closing the regional undersea gap with China’s technological assistance. Although limited by noisier propulsion and lower stealth compared to India’s Kalvari-class, its operational persistence and SLCM capability provide significant asymmetry.

India’s edge in acoustic discretion and sensor integration remains, but until P-75I submarines become operational, Pakistan’s cumulative AIP fleet (Agosta + Hangor) will dominate the endurance spectrum in the northern Indian Ocean.

IDN (With Agency Inputs)