Comparison Hangor Versus Scorpene Class Tactics and Employment

The Hangor Killer

Pakistan's first Hangor-class submarine, built under an agreement with China, arrived at Karachi Port on June 11 with much fanfare.

The Hangor Class stands out equipped with Air-Independent Propulsion (AIP) for extended underwater endurance. This will enhance the Pakistan Navy’s stealth endurance and offer options for long-range strikes in deep waters.

A comparison with the Scorpene-class submarines the most advanced with the Indian Navy may be in order even though these do not feature an AIP.

In size, the Hangor displaces 2800 tonnes compared to the Kalvari class's 1775 tonnes, allowing the former to field more crew and weapons but restricting operations to deep waters. In addition, detection due to enormous size is easier than the smaller Kalvari class boats.

The AIP provides an advantage to the Hangor class to remain submerged for much longer periods without surfacing or snorkelling. The Hangor is equipped with Stirling-cycle AIP enabling weeks of submerged stealth rather than surfacing often.

The Chinese are reported to have procured the Stirling AIP technology from the Swedish shipbuilder Kockums, which they reverse-engineered and incorporated into the Yuan-class submarines including the fielding of a massive 320 kW Stirling engine which needs confirmation.

The Hangor class has multiple moving mechanical parts that generate a slight acoustic signature compared to modern, vibration-free fuel cells operated by the Scorpene.

The two classes uniformly field six 21-inch torpedo tubes. For anti-ship and land-attack missions, the Kalvari-class fields proven systems like French Exocet missiles and the supersonic BrahMos, whereas the Hangor-class is equipped with Chinese-origin anti-ship missiles and Submarine-Launched Cruise Missiles (SLCMs)

In terms of sensors, the Kalvari leverages widely used, combat-tested French sonar and combat management systems. While adequate information of the sensor suite of the Hangor Class is not available, it can be expected to field a modern array of sonars, EW suites and optronics.

The AIP does not by itself provide the Hangor Class and advantage as the first impression gives, but underwater tactics and employment will finally determine the success of the submarine class.

The Hangor will be facing the Indian Navy’s very capable Anti-Submarine Warfare network, operating across multiple domains, from the Boeing P-8I Neptune maritime patrol aircraft, armed with advanced AN/APY-10 radars, sonobuoys, and Mark 54 lightweight torpedoes.

Despite the Hangor's AIP system, its large 2,800-ton frame leaves a larger acoustic and magnetic signature, making it a prime target for a P-8I's sensor array.

In littoral waters, India also deploys specialised ASW platforms like the Kamorta-class stealth corvettes and the newer Arnala-class ASW Shallow Watercraft which use advanced hull-mounted and towed-array sonars, thus restricting operations by the Hangor class in littoral waters.

The Kalvari-class submarines will be most vulnerable when they surface to recharge batteries. Pakistan Navy's RAS 72 Sea Eagle maritime patrol aircraft features Leonardo Seaspray AESA radars optimised to detect small targets—such as a submarine's periscope or snorkel mast.

On the other hand, Kalvari class also exploits littoral manoeuvrability to hide in thermal layers closer to the coast and data relays from friendly Indian surface groups to time its high-risk battery-charging cycles when enemy aircraft are out of range.

In essence tactics and employment will determine the advantage and not merely the AIP of Pakistan Navy's Hangor Class subs over the Indian Navy's agile and silent Scorpene Class.