INS Khukri (F149)

After the beginning of hostilities on 3 December 1971, Indian Naval radio detection equipment identified a submarine lurking about 35 miles (56 km) south-west of Diu harbour. The 14th Frigate Squadron of the Western Fleet was dispatched to destroy the submarine.[2] It normally consisted of five ships, Khukri, Kirpan, Kalveti, Krishna and Kuthar, but at the time of the incident Kuthar's boiler room was being repaired in Bombay.[2] 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 anti-submarine aircraft.[5]

The submarine sighted the squadron on the evening of 9 December. Khukri was still not aware of the submarine's presence[6] and continued slowly on a steady course because she was testing an improved version of the 170/174 sonar, which required a low speed to increase detection, despite the fact that moving on low speed was against Indian anti-submarine doctrine.[2] At 19:57 Hangor fired a homing torpedo on a sonar approach at Kirpan.[2] The torpedo did not explode[6][7] and was detected by Kirpan which turned away and fired anti-submarine mortars.[2] Khukri increased its speed and turned towards the submarine, which then fired a second torpedo directed at Khukri.[2] The torpedo struck Khukri and exploded under its oil tanks.[2][6] According to the Pakistani submarine captain, Commander Ahmed Tasnim, the ship sank within two minutes.[7] Other sources claim that Khukri was struck by three torpedoes before going down.[8]

After a few minutes, Kirpan attacked Hangor with depth charges, as her anti-submarine mortars were no longer functional.[2] Hangor then fired a final torpedo at Kirpan before leaving the area.[2][6] Hangor patrolled the region for the next four days before returning safely to her berth.

Khukri is the only ship lost in combat in the history of the Indian Navy.[2][3][9] Eighteen officers and 176 other sailors were killed.[3][9] The captain, Mahendra Nath Mulla, was among the casualties and is the only Indian captain to go down with a vessel as INS Khukri is the only warship of Indian navy lost in combat. He was posthumously awarded India's second-highest military honour, the Maha Vir Chakra.[3][9]

There is a memorial to the sailors in Diu. The memorial consists of a scale model of Khukri encased in a glass house, placed atop a hillock facing the sea. The memorial was inaugurated by Vice Admiral Madhvendra Singh as the flag officer commanding-in-chief.[4]

INS Khukri during an execise with Indonesian Navy in 1960

Model of Khukri at the INS Khukri memorial, Diu

INS Khukri memorial, Diu

Responsibility for errors by Indian naval officers related to the sinking has caused some controversy. The naval officer who led the inquiry into the sinking, Benoy Bhushan, has claimed that India's official naval history invented fictional accounts to cover up bungling and a surviving sailor from the frigate, Chanchal Singh Gill, has called for an investigation and withdrawal of gallantry awards to negligent officers in the squadron.[10]

• Mankekar, D.R. (1972). Twenty-Two Fateful Days: Pakistan Cut to Size. New Delhi: Indian Book Co.
• Roy, Mihir K. (1995). War in the Indian Ocean. Lancer International.
• "Indian Navy - Blackwood Class Type 14 Frigates". Marine News Supplement: Warships. 76 (5): S277–S281. May 2022. ISSN 0966-6958.

• Bharat Rakshak's article on the incident

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