December, 1971 How INS Khukri was sunk?
On 22 November 1971, PNS Mangro, a Hangor-class diesel-electric submarine, under the command of Lieutenant-Commander Shamim, was deployed to patrol off the Arabian Sea.
On November 26, PNS Hangor, a Daphne-class diesel-electric submarine with a load of torpedoes, under the command of Commander Ahmed Tasnim, sailed from its base to patrol the Bombay Harbour.
PNS Mangro was ordered back to base and on December 2, PNS Mangro reported back to her base.
On December 2, PNS Hangor, “remaining submerged in a northerly direction, investigated radio transmissions intercepted from the warships belonging to the Western Naval Command of the Indian Navy that would launch a first missile attack on Karachi.
PNS Hangor was passed over by the large Squadron of the Western fleet of the Indian Navy. The cruiser INS Mysore passed directly over” PNS Hangor. Hostilities began on the 3rd of December 1971.
On December 7/8, either the Indian Navy’s radio detection equipment or “Indian intelligence picked up transmissions from a Pakistani submarine 35 miles south-west of Diu Head”. Admiral Sardarilal Mathradas Nanda, Chief of Naval Staff, ordered the despatch of the 14th Frigate Squadron of the Western Fleet to destroy PNS Hangor.
The 14th Frigate Squadron normally consisted of five ships INS Khukri, INS Kirpan, INS Kalveti, INS Krishna and INS Kuthar but the Frigate Squadron that went with the intention of destroying PNS Hangor had four-INS Kuthar was missing. On December 9
PNS Hangor “picked up two sonar contacts. Their sonar and radar transmissions identified them as warships…engaged in a rectangular anti-submarine search.
” By 19:00, PNS Hangor “was in a position and the two Indian surface ships were approaching on a steady course with a narrow weave, at a speed of 12 knots.” At 19:15, PNS Hangor “went to action stations. At 19:30 she came to periscope depth.
The radar showed the range to be 9,800 meters, but the ships were darkened and could not be seen, so the decision was made to dive to 55 meters and rely exclusively on sonar for the approach and attack.” Amazingly, the Indian warships failed to detect PNS Hangor. On December 9 at 19:57, PNS Hangor fired a torpedo at INS Kirpan.
Apparently, “the torpedo failed to explode, but was detected by INS Kirpan, who turned away and fired anti-submarine mortars.
INS Khukri increased speed and turned towards PNS Hangor, who fired a second torpedo at INS Khukri.
After five minutes, the torpedo exploded under the INS Khukri’s oil tanks, and INS Khukri began to sink.’
INS Kirpan, the Indian Navy’s anti-submarine warfare frigate, “turned back to attack the PNS Hangor with depth charges (her anti-submarine mortars had broken down) and PNS Hangor fired another torpedo at INS Kirpan before turning away and exiting at maximum speed.
INS Kirpan outran the torpedo and later returned with another ship, INS Katchal, to rescue INS Khukri’s survivors.”
For the record, the sinking of INS Khukri, a Type 14 Blackwood-class frigate of the Indian Navy, by PNS Hangor (nicknamed: ‘Shark’), a Daphne-class diesel-electric submarine, is the “only recorded submarine kill after World War II until the Falklands War, when the Royal Navy’s nuclear submarine, HMS Conqueror, sank the Argentine Navy cruiser, General Belgrano.”
Following the sinking of INS Khukri, the “Indian Navy and Air Force mounted Operation Falcon, a major anti-submarine operation involving ASW ships, Sea King helicopters and Alize ASW/strike aircraft.”
On December 18, PNS Hangor returned back to Karachi. The sinking of INS Khukri had far reaching consequences. The morale within the Pakistan Navy went through the sky.
The Indian Navy, under strategic pressure, cancelled ‘Operation Triumph’, the third missile attack, that was due to be launched on December 10.
