INS Khukri (1958) - Incident

Incident

After the beginning of hostilities on 3 December 1971, Indian Naval radio detection equipment identified a submarine lurking about 35 miles south-west of Diu harbour.

The 14th Frigate Squadron of the Western Fleet was dispatched on a hunter-killer mission to destroy the submarine. The 14th Frigate Squadron normally consisted of three ships Khukri, Kirpan and Kuthar (all named after types of dagger). But only two were involved in the incident as Kuthar's boiler room was being repaired in Bombay. One reason that may have prompted the decision to deploy two obsolete Blackwood-class frigates against a modern Daphne-class submarine was that the Indian Navy lacked sufficient numbers of airborne anti-submarine planes.

In the early hours of 9 December, Hangor picked up two sonar contacts in the area. The sonar and radar transmissions identified them as warships but Hangor failed to intercept them and lost contact when the range increased.

The submarine sighted the squadron on the evening of 9 December. Khukri was still not aware of the submarine's presence and continued doing slow speed on a steady course because she was testing an improved version of the 170/174 sonar, which required a slow speed to increase detection, despite the fact that moving on slow speed was against Indian anti-submarine doctrine. At 19:57 Hangor fired a homing torpedo on a sonar approach at Kirpan. The torpedo failed to explode and was detected by Kirpan which turned away and fired anti-submarine mortars. Khukri increased its speed and turned towards the submarine, which then fired a second torpedo directed at Khukri. The torpedo struck Khukri and exploded under its oil tanks. According to the Pakistani submarine captain, Commander (later Vice Admiral) Ahmed Tasnim the ship sank within two minutes. Other sources claim that Khukri was struck by three torpedoes before going down.

After a few minutes, Kirpan turned back to attack Hangor with depth charges, as the her anti-submarine mortars had broken down. Hangor then fired another torpedo at Kirpan before turning away and exiting at maximum speed. Kirpan outran the torpedo and quickly disengaged returning later with another ship, Katchal, to search for the survivors from Khukri. Hangor patrolled the region for the next four days before returning safely to its berth.