India's Scorpène Submarines with DRDO's Fuel-Cell AIP: A Technological Leap Over Pakistan's Hangor-Class Fleet

Recent discussions have emerged following statements by Commodore (R) Syed Muhammad Obaidullah of the Pakistan Navy, who asserted the superiority of Pakistan's Chinese-supplied Hangor-class submarines over India's French-designed Scorpène-class vessels. While Obaidullah highlighted the advantages of the Chinese Air Independent Propulsion (AIP) system in the Hangor-class, a closer examination reveals a more nuanced perspective.

Hangor-Class Submarines: Stirling Engine-Based AIP

The Hangor-class submarines, an export variant of China's Type 039A Yuan-class, are equipped with a Stirling engine-based AIP system. This technology allows submarines to remain submerged longer than traditional diesel-electric models by using external combustion engines that operate quietly. However, Stirling engines require liquid oxygen storage and are not as efficient or silent as more advanced AIP systems. Additionally, these engines involve mechanical components that may necessitate regular maintenance, potentially affecting operational readiness.

Scorpène-Class Submarines: Embracing DRDO's Fuel-Cell AIP

In contrast, India's Scorpène-class submarines are set to be retrofitted with an indigenously developed Fuel-Cell AIP system by the Defence Research and Development Organisation (DRDO). This system generates electricity through a chemical reaction between hydrogen and oxygen, producing water as a byproduct. Notably, the DRDO's design includes onboard hydrogen generation, eliminating the need for storing hydrogen, which enhances safety and operational efficiency.

Fuel-cell AIP systems offer several advantages:

• Enhanced Stealth: They operate silently, reducing the acoustic signature and making detection by adversaries more challenging.
• Extended Endurance: Submarines can remain submerged for longer periods without surfacing, providing a tactical advantage.
• Reduced Maintenance: With fewer moving parts compared to Stirling engines, fuel-cell systems are less prone to mechanical issues, ensuring higher availability.

Comparative Analysis: Technological Edge

While the Hangor-class submarines' Stirling engine-based AIP provides improved underwater endurance over conventional systems, the DRDO's fuel-cell AIP represents a more advanced solution. The integration of this technology into India's Scorpène-class submarines is anticipated to offer superior stealth, longer submerged operations, and enhanced reliability.

Furthermore, reports suggest that the Hangor-class submarines are equipped with Chinese-made diesel generators, which may produce more noise compared to the German MTU engines originally intended for these vessels. This increased noise could compromise their stealth capabilities, a critical factor in submarine warfare.

Conclusion

While the Hangor-class submarines enhance Pakistan's naval capabilities, assertions of their superiority over India's Scorpène-class should be reconsidered. The forthcoming integration of DRDO's Fuel-Cell AIP into the Indian submarines is poised to shift the balance, offering technological advancements that may outpace the capabilities of the Hangor-class fleet.