The Indian Navy inducted the sixth and final submarine of the P-75 Scorpene Project, along with a stealth frigate and a guided missile destroyer. Though an unprecedented feat, the Air Independent Propulsion (AIP) technology still eludes the Indian Navy’s submarine fleet. In contrast, the Chinese-built Hangor class submarine is likely to enter the Pakistan Navy’s fleet as scheduled.
The Indian Navy doesn’t operate a single AIP-equipped submarine yet. Meanwhile, the Pakistan Navy’s all three French Agosta-90B (PNS Khalid, Saad, and Hamza) are powered by AIPs.
As per the current progress, the Hangor submarines are expected to join the Pakistan Navy by the late 2020s and early 2030s. Upon completion, the submarines will join the Pakistan Navy’s fleet, taking the strength of its AIP-equipped boats to 11.
Despite being cash-strapped, Pakistan is matching the prowess of the Indian Navy ship by ship. As the only Indian Navy-operated port in the country is coming to life and set to become the largest naval base east of the Suez Canal, Pakistan has also accelerated its efforts to have one of Asia’s largest naval fleets by enlarging its surface fleet to 50 warships along with a subsurface fleet of 11 submarines. Of the 50 surface ships the Pakistan Navy aspires to operate, 20 are expected to be “major surface vessels” like frigates and corvettes.
Admiral Naveed Ashraf, Chief of the Naval Staff of the Pakistan Navy, told Chinese state media that the construction of four of these submarines is progressing as per the timeline.
Admiral Ashraf said that the Hangor-class submarines will significantly enhance Pakistan’s naval capabilities with their improved stealth, maneuverability, and firepower, allowing our Navy to execute a wide range of operations effectively.
“The project is proceeding as per the timeline. We expect that these submarines will join the Pakistan Navy fleet very soon,” Ashraf said.
In December 2021, the fifth Hangor-class conventional submarine, also the first one to be built in Pakistan, had the steel cutting ceremony. With it, Pakistan will gain invaluable experience in building the world’s top-class modern submarine.
The Hangor submarines are S-26 variants based on the Chinese Yuan class submarines but developed for exports. Several design changes were made to the standard-grade S-26.
The Hangor class submarine is larger, with a displacement of 2,800 tons compared to the S26’s 2,550 tons. But it has a slightly shorter hull (76 m to the S26’s 77.7 m). Both have the same payload capacity of six torpedo tubes and a Stirling-based AIP system.
Earlier, the S-26 submarines were powered by the German MTU 12V 396 SE84 diesel engine, but the German government reportedly withheld export licenses for the powerplant. Later, the Pakistan Navy decided to go with the Chinese CHD-620 diesel engine, delaying the program.
These submarines are equipped with advanced sensors and modern armaments, which slightly tilts the tactical power balance in favor of Pakistan. These diesel attack submarines align with the Pakistan Navy’s offensive sea denial strategy, which prioritizes using submarines and missile-carrying maritime patrol aircraft in naval warfare.
AIP-powered conventional diesel-electric submarines (SSK) are midway between nuclear-powered boats and non-AIP SSKs. It allows an SSK to remain submerged for 10 to 14 days without needing to surface to charge its batteries, which might get it detected. Other SSKs can stay underwater for roughly 48 hours. The fuel-cell-based AIP is unique, as it generates its hydrogen requirement on board.
An AIP enhances a submarine’s underwater endurance between battery charges by three to four times, thus reducing its vulnerability to detection.
Indian Submarine Fleets’ Slow Progress Towards AIP
With the induction of INS Vaghsheer, the Indian submarine fleet currently has 17 conventional submarines. The Scorpene Class submarine will be retrofitted with an indigenous AIP system when the first submarine in the class, INS Kalvari, undergoes major refit.
Retrofitting the operational submarine would require cutting it into halves and inserting a new AIP section, increasing its length and weight. French shipbuilder Naval Group will assist in the complex procedure.
After this, the technology will undergo further testing before being fitted into the remaining Scorpene-class submarines. Experts have pointed out that upgrading a weapons platform with new technology will reduce operational readiness, as the repairs will take at least a year.
Apart from the six recently built submarines, the rest are over 30 years old and approaching their decommissioning date. India’s aging Shishumar (HDW) class and Sindughosh (Kilo) class submarines are facing spare parts issues because of Russia’s Ukraine war.
The Indian Navy is also scouting for a foreign vendor to build AIP-equipped submarines under Project-75I. It has already done field evaluations of the system offered by Germany and Spain. However, it is yet to be finalized who gets the contract.
Considering it took 11 years for the first Scorpene class submarine to enter the Indian Navy’s fleet after signing the deal, the subs to be built under Project 75I are at least a decade away from entering operation.
Pakistan-China Cooperation
Pushed by China, Pakistan has woken up to the importance of the Western Indian Ocean and, hence, the push for the navy’s modernization.
Apart from the Hangor class submarine, Admiral Khalid talked about four Type 054A/P frigates built by China and how they have bolstered the country’s warfighting capabilities.
“The induction of Type 054 A/P frigates in the Pakistan Navy Fleet has bolstered our warfighting capabilities and enhanced operational flexibility, and these ships will remain the mainstay of the Pakistan Navy Fleet in coming years.”
The last two of the frigates were delivered in May 2023. The Type 054A/P is one of the latest multi-role frigates of Chinese origin, equipped with state-of-the-art weapons and sensors that include CM-302 surface-to-surface missiles and LY-80 surface-to-air missiles, as well as an Advanced Anti-Submarine Warfare suite and Combat Management System, enabling ships of this class to operate under multi-threat scenarios. The Pakistan Navy has been the first customer of these frigates.
The Pakistan Navy Chief said that Type 054 A/P ships are equipped to operate under multi-threat scenarios and have been fully integrated into Pakistan Navy operations. The F-22P guided missile frigate, built by China and rechristened as PNS Zulfiquar by the Pakistan Navy, conducted Operation Himalayan Spirit in the North Arabian Sea in October 2024. The Pakistan Navy seized 1.3 tons of narcotics during the operation.
