PNS Hangor (S131) - Indo-Pakistan War of 1971

Indo-Pakistan War of 1971

On midnight, 2 December 1971, in an attempt to locate a number of possible enemy contacts, PNS Hangor continued her patrol in a northerly direction to investigate radio transmissions intercepted by on-board monitoring equipment. Two contacts were picked up on passive sonar and were identified as warships. The initial range was 6 to 8 miles. The submarine began to stalk the contacts, but an early attempt to gain an attack position on the identified ships failed when the PNS Hangor could not match the surface ships' speed. The submarine's crew however managed to predict the target ships' movements and succeeded in working its way into a tactically advantageous position along the path of the patrolling frigates by 19:00.

On the night of 2 and 3 December 1971, the PNS Hangor, while lying in wait off Bombay, detected a large formation of ships from Indian Navy's Western fleet which included cruiser INS Mysore. As the Indian Naval fleet passed by Hangor very closely, all transmissions were silenced to avoid detection by the Indian fleet. Upon reinstating communications, the PNS Hangor provided advance intelligence of a possible attack by the observed Indian armada near the Karachi coast and passed an alert to Pakistani forces stationed in Karachi. These transmissions were intercepted and identified by the Indian Navy. On 3 December, the Indian Navy dispatched two ASW frigates, INS Khukri and the INS Kirpan of 14 Squadron - Western Naval Command.

On 9 December 1971, 19:00 hours, PNS Hangor detected the possible signature of the two Indian frigates dispatched in response to the intercepted communications. Later, around midnight, Commander Tasnim ordered the PNS Hangor to dive deep to carry out a blind (Sonar only) approach and attack. The attack team concentrated on tracking the two targets as they gradually came within firing range. At 19:57 the submarine fired a down-the-throat shot with a Homing torpedo at the INS Kirpan from a depth of 40 meters. The torpedo was tracked but no explosion was heard. It was then speculated that the torpedo has missed its target, and the moment INS Kirpan sensed the torpedo, the Captain of INS Kirpan realized that the ship was under attack turned away at maximum speed. Hangor had struck first, but had failed to hit hard.

As INS Kirpan fled the battle, INS Khukri, to its south, knowing the direction from which the torpedo had come, increased speed and came straight for an attack on Hangor. As INS Khukri came in for an attack, Hangor’s attack team shifted targeting to Khukri, quickly obtaining a solution and fired a second torpedo. The second torpedo was fired on the approaching INS Khukri and was followed by a heavy and loud explosion as the torpedo impacted the INS Khukri. Shortly before the impact, Hangor detected the direct orders of INS Khukri’s Commanding Officer Captain Mahendra Nath Mulla ordering evasive maneuvers, however, Khukri was unable to avoid the torpedo. Hangor moved into position to search for possible survivors, however, with the Khukri sinking in matter of two minutes, all hands were lost. The casualty roster listed 18 officers and 176 sailors aboard the INS Khukri. It remains as Indian Navy's most costly wartime casualty in terms of lives lost.

Witnessing the INS Khukri sinking as she did, aggravated the Commanding Officer of her sister ship, the INS Kirpan. The Kirpan engaged the PNS Hangor with a hasty emergency attack. Sinking a pattern of depth charges, the Kirpan hoped to drive the Hangor into retreat. However, Hangor continued the engagement, firing a third torpedo locked on to the INS Kirpan's tail. INS Kirpan quickly disengaged, and increased her speed and successfully evaded the torpedo. Though it is reported that it got damaged in the attack. Hangor disengaged by turning west towards deeper waters. Hangor continued to patrol for another 4 days till the night of 13 December 1971 when she returned safely to her berth. While celebrating her victory, the second half of the mission, with PNS Ghazi under the command of Commander Zafar Muhammad Khan patrolling in water near Vishakapatnam, Bay of Bengal, sank mysteriously when its own mine exploded on it. All hands aboard the PNS Ghazi died when the submarine sank on the night of 4 December 1971.