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Operation Trident
Part of Indo-Pakistani War of 1971
Date4–5 December 1971
LocationArabian Sea, 14 to 70 nmi south of Karachi port, Pakistan

Strategic Indian naval victory[1][2]

Partial Naval Blockade on Pakistan
 Indian Navy  Pakistan Navy
Commanders and leaders
Admiral Sardarilal Mathradas Nanda
Commander Babru Bhan Yadav
Rear Admiral Hasan Ahmed
CDRE Hanif Ali
CDRE Patrick J. Simpson
3 Vidyut class missile boats
2 anti-submarine Arnala class corvettes
Unknown number of ships
Casualties and losses

Minesweeper PNS Muhafiz sunk[6][7]
Destroyer PNS Khaibar sunk[6][7][8]
Transport, MV Venus Challenger, sunk[7][9]
Destroyer PNS Shah Jahan badly damaged[6][9][10]
Karachi harbour fuel storage tanks destroyed[6]
100+ sailors killed[citation needed]

700+ injured[citation needed]

Operation Trident and its follow-up Operation Python were naval offensive operations launched on Pakistan's port city of Karachi by the Indian Navy during the Indo-Pakistani War of 1971. Operation Trident resulted in the first use of anti-ship missiles in the region,[11] as well as the first sinking of naval vessels during hostilities in the region since World War II.[6] India celebrates its Navy Day annually on 4 December to mark this operation.


Karachi housed the headquarters of the Pakistani Navy and almost the entire Pakistan Navy fleet was based at Karachi Harbour. Karachi was also the hub of Pakistan's maritime trade, meaning that a blockade would be disastrous for Pakistan’s economy. The defence of Karachi harbour was therefore paramount to the Pakistani High Command and it was heavily defended against any air or naval strikes. Karachi received some of the best defence Pakistan had to offer, as well as cover from strike aircraft based at two airfields in the area.

Operation Trident was planned under the leadership of Admiral Sardarilal Mathradas Nanda. The Indian Navy's Vidyut class missile boats, had limited range. So the plan for Operation Trident called for towing the missile boats towards Karachi and including a refuelling tanker in the task force to enable the task force to return to Indian ports.[12] The Vidyut class vessels were each armed with four SS-N-2B Styx surface-to-surface missiles with a maximum range of 40 nmi and a firing system linked to long-range MR-331 Rangout radars.

Operation Trident

On 4 December, the Indian Navy launched a fast naval strike on the Pakistan Naval Headquarters (PNHQ) of Karachi.[13] The task group for the operation consisted of three Vidyut class missile boats, INS Nipat (K86), INS Nirghat (K89) and INS Veer (K82) from the 25th "Killer" Missile Boat Squadron, escorted by two anti-submarine Arnala class corvettes, INS Kiltan (P79) and INS Katchall (P81), and a fleet tanker, INS Poshak.[6][13] The task group was led by the Commanding Officer of the 25th Squadron, Commander Babru Bhan Yadav, embarked on INS Nipat.

As per the operational plan, the task group reached 250 nautical miles (460 km) south of Karachi and stayed in the area during the day, outside the range of Pakistan Air Force (PAF) aircraft. The plan was to attack Karachi at night because most PAF aircraft did not possess night-time bombing capability.[14] In the evening on 4 December, INS Kiltan and the 3 missile boats approached Karachi, evading Pakistani reconnaissance aircraft and surface patrol vessels.

At 2230 hrs PST, the task group converged about 70 nautical miles (130 km) south of Karachi detected Pakistani targets, analysed as warships 45 miles to the northwest and 42 miles to the northeast.

INS Nirghat then steered towards and engaged the northwesterly target and after verification, fired the first SS-N-2B Styx missile at the destroyer, PNS Khaibar, which was on patrol. Khaibar mistook the missile to be an aircraft and engaged it with its Bofors anti-aircraft guns. The missile struck Khaibar on the starboard side and exploded below the aft galley in the Electrician's mess deck at about 2245 hrs PST. The ship immediately lost propulsion, plunged into darkness and the No.1 Boiler room exploded, engulfing the ship in thick black smoke. Khaibar sent out an emergency transmission to PNHQ which read "Enemy aircraft attacked in position 020 FF 20. No 1 Boiler hit. Ship stopped." In the panic of the attack, the transmission sent incorrect coordinates of the ship's position, which resulted in delays in rescuing the survivors later. With the target still afloat, at about 2249 hrs, INS Nirghat fired a second missile, which was seen approaching and again engaged with anti-aircraft guns of Khaibar. The missile struck the No.2 Boiler room on the starboard side, sinking PNS Khaibar.[10]

At 2300 hours, INS Nipat engaged two targets to the northeast approaching Karachi. Verifying the targets, Nipat launched 1 Styx missile each at the MV Venus Challenger and her destroyer escort PNS Shah Jahan (DD-962).[9][10] By Indian claims[10][15][16] the MV Venus Challenger was carrying ammunition for Pakistan from the United States forces in Saigon. The ammunition on the Venus Challenger immediately exploded as the missile struck sinking her about 26 miles south of Karachi.[15] The other missile hit PNS Shah Jahan which was badly damaged and scrapped.[7][8][10]

At 2320 hours, the minesweeper PNS Muhafiz, was targeted by a Styx missile from INS Veer. The missile hit Muhafiz on the port side abaft the bridge, instantaneously disintegrating the vessel before it could send a transmission to the PNHQ.

INS Nipat continuing towards Karachi, locked on to the Kemari oil storage tanks of the port from 14 nautical miles (26 km) south of the harbour. It fired two missiles at the tanks. One of the missiles misfired, while the other hit the fuel tanks, which were burnt and destroyed, causing heavy loss.[6] The task force then withdrew back towards Bombay. The operation Trident was also noted for introducing the first ship launched missiles in the region, to the war.[6]


Overall, the Indian Navy's missile attack was carefully planned and executed well. The attack achieved complete surprise and was a shock to Pakistan's Armed Forces Command. A disjointed and haphazard rescue operation was launched to locate and recover survivors of PNS Khaibar, while PNHQ was not aware of the sinking of PNS Muhafiz. PNHQ learnt of the fate of Muhafiz from her survivors who were rescued when a patrol vessel steered towards her burning flotsam while searching for survivors from the Khaibar.[citation needed]

Pakistan Airforce retaliated to these attacks by bombing Okha harbour scoring direct hits on fuelling facilities for missile boats, ammunition dump and the missile boats jetty.[17][18] Indians were ready for this and had already moved the missile boats to other locations to prevent any losses.[15] But the destruction of the special fuel tank prevented any further incursions until Operation Python.[15]

The Pakistan Navy, on high alert as a result of the operation, raised a number of false alarms in the ensuing days about the presence of Indian Navy vessels off Karachi. One such false alarm was raised by a Pakistan Navy Fokker Friendship reconnaissance aircraft on 6 December 1971 which reported a Pakistan Navy frigate as a missile boat by Indian Navy.[13] The PNHQ ordered a Pakistan Air Force (PAF) air strike on the supposed Indian ship. At 0645 hrs, fighter jets were scrambled which strafed the vessel before it was identified as Pakistan Navy's own frigate PNS Zulfiqar, which suffered casualties and damage as a result of this friendly fire.[13]

Operation Trident was considered an enormous success for the Indian Navy with no casualties or damage to the Indian task group,[6] which returned safely back to Indian ports. The success of this operation prompted another successful attack on Karachi on 8 December 1971, known as Operation Python.[13]


The Indian Navy celebrates its Navy Day on 4 December, to mark the operational victory.

A number of Indian Navy personnel were honoured with gallantry awards for the operation. Then Fleet Operations Officer and later Vice Admiral Gulab Mohanlal Hiranandani, was awarded the Nausena Medal for the detailed operational planning.[19]

Maha Vir Chakra

  • Commander Babru Bhan Yadav, for planning and leading the task force.

Vir Chakra

  • Lieutenant Commander Bahadur Nariman Kavina, commanding officer of INS Nipat[20]
  • Lieutenant Commander Inderjit Sharma, commanding officer of INS Nirghat
  • Master Chief M. N. Sangal, INS Nirghat


  • S.M.Nanda (2004). The Man Who Bombed Karachi. HarperCollins India. ISBN. 


  1. 1.0 1.1 "BLOCKADE FROM THE SEAS". THE INDIAN NAVY AT WAR: 1971. bharat-rakshak. Retrieved 27 October 2011. 
  2. "Our superiority will prevail". Retrieved 27 October 2011. 
  3. "China's pearl in Pakistan's waters". 4 March 2005. Retrieved 27 October 2011. 
  4. "History". Indian Navy. Indian Defence. Retrieved 27 October 2011. 
  5. Mustafa, Malik Qasim. "MARITIME SECURITY: THE ROLE OF PAKISTAN NAVY". Strategic Studies. The Institute of Strategic Studies, Islamabad. Retrieved 27 October 2011. 
  6. 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 "Indo-Pakistani War of 1971". 
  7. 7.0 7.1 7.2 7.3 Hiranandani, G. M. (1965–1975). Transition to triumph: history of the Indian Navy. Barnes&Noble. 
  8. 8.0 8.1 Petrie, John N.. American Neutrality in the 20th Century: The Impossible Dream. DIANE Publishing. pp. 110. 
  9. 9.0 9.1 9.2 "Anti-Shipping Strike Combat Losses – Post 1966". Warship Vulnerability. Retrieved 27 October 2011. 
  10. 10.0 10.1 10.2 10.3 10.4 Harry, B.. "Trident, Grandslam and Python: Attacks on Karachi". Pages from History. Bharat Rakshak. Retrieved 28 October 2011. 
  12. "Indian Navy’s War Hero passes away: Cmde Babru Yadav led the Missile Boat Attack on Karachi in 1971". 
  13. 13.0 13.1 13.2 13.3 13.4 "Trident, Grandslam and Python: Attacks on Karachi". 
  14. "How west was won…on the waterfront". 
  15. 15.0 15.1 15.2 15.3 "NAVAL OPERATIONS IN THE WESTERN NAVAL COMMAND". Indian Navy. 
  16. "1971 War: The First Missile Attack on Karachi". Indian Defence Review. Retrieved 31 October 2011. 
  19. "Vice-Admiral Hiranandani cremated with full Naval honours". The Hindu. 3 September 2009. Retrieved 2012-01-19. 

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