By Faisal Nadeem
For Pakistan Navy, submarines have always played a pivotal role during both 1965 and 1971 wars. Despite having a limited role to play in both wars due to land centric nature of wars, submarines of Pakistan Navy always dominated themselves in Arabian Sea. In this regard, 09 Dec is annually celebrated as ‘Hangor Day’ to mark the achievements of PNS Hangor during the 1971 war. This piece revisits that part of history by describing the evolution of PNS Hangor in Pakistan Navy. Following the 1965 war, Indian Navy underwent a rapid modernization and expansion. Consequently, Pakistan Navy started focusing on strengthening its existing submarine fleet. The then Pakistani government began the process of acquiring Daphné-class submarine from France, including PNS Hangor. Hangor was the lead ship of Daphné-class diesel-electric submarine and was designed and constructed by France. It was commissioned into Pakistan Navy in 1969. During the 1971 turmoil in East Pakistan, Pakistan Navy’s offensive capabilities largely hinged on the small and nascent submarine force. In view of the increasing chances of war, the Pakistan Navy submarines undertook a few patrols to gather intelligence and picked up vital operational information for war time submarine operations. The longest patrol was over 30 days by PNS Hangor.
On 22 Nov 1971, PNS Hangor patrolled off towards Indian Kathiawar coast. On the very same day, Indian Army launched a full scale invasion of East Pakistan. Unheard of Indian intrusion, crew of PNS Hangor continued to proceed towards the designated area for a reconnaissance patrol amidst heavy Indian air activity. After reaching the designated area, the submarine crew started patrolling the region. For next few days, PNS Hangor patrolled in various areas with no success. On 02 Dec, sensors of the submarine picked up several radar transmissions originating from Bombay harbour. These transmissions were analyzed and assessed to be of Indian warships. The operations team of the PNS Hangor correctly assessed that a formation of six escorts from Indian Western Fleet was sailing out from Bombay (presently Mumbai). At that time, Pakistan was engaged in an all-out war in its eastern part only. Therefore, PNS Hangor was not directed to engage the incoming Indian fleet. Aggrieved over missing an opportunity to strike enemy nearby, the efforts of PNS Hangor’s crew were not to go in vain.
The presence of PNS Hangor in Indian waters forced the Indian fleet to split up, move toward south and forfeit its envisaged attack plans. Additionally, Indian Navy has to abandon its planned missile attack on Karachi harbour on the night of 05 Dec because of PNS Hangor’s presence in Indian waters. Meanwhile, PNS Hangor continued her patrol and extend her patrol northwards to investigate some intercepted radio transmissions. On 09 Dec, the submarine detected two contacts which were later found out to be two anti-submarine frigates off the Kathiawar coast. The Indian frigates were doing a rectangular anti-submarine search. By night, PNS Hangor placed itself on the estimated track of the targets (Indian frigates). The conditions in which Pakistani submarine was to target Indian frigates were not conducive for submarine operations due to shallow depth in the area. Against these odds, PNS Hangor targeted Indian Navy Frigate INS Khukri and INS Kirpan. PNS Hangor engaged both Indian naval ships 30 miles southeast off ‘Diu Head’, a headland in Arabian sea. INS Khukri sunk down within two minutes. 18 officers and 176 sailors lost their lives in the downing of the Indian frigate. On the other hand, INS Kirpan was severely damaged. The downing of INS Khukri was the first such incident in which a conventional submarine downed anti-submarine frigate through a torpedo attack. After targeting both Indian frigates, Indian Navy launched a massive anti-submarine effort i.e. Operation Falcon for hunting down PNS Hangor. The four day operation, which was launched on the night of 9th December, utilizing all available anti-submarine ships, shore-based surveillance aircraft, specialized anti-submarine naval aircraft Alice and Sea King anti-submarine helicopters in Hunter-Killer Groups to hunt down Pakistani submarine. The Indian naval search operation combed the area stretching from southwest of Diu Head, where INS Khukri was sunk.
It is pertinent to mention here that a submarine evasion following an attack is more complicated and challenging than the submarine attack itself due to various inherent conventional submarine limitations which include submerged endurance. Against all odds, PNS Hangor reached Karachi on 18 Dec. The accomplishments of PNS Hangor during 1971 war demonstrated tactical superiority of Pakistan Navy in subsurface warfare. On strategic level, Indian Navy had to cancel ‘Operation Triumph’, the third missile attack to be launched on 10 Dec. Additionally, the involvement of Indian western fleet in Operation Falcon for four days eased off pressure on Pakistani coast. For their act of courage and devotion to duty, the officers and men of PNS HANGOR were decorated with a number of highest operational gallantry awards given to a single unit of Pakistan Navy. PNS Hangor continued to serve Pakistan Navy with distinction until it was decommissioned in Jan 2006. It was later converted into a museum ship at Pakistan Maritime Museum in Karachi.