Operation Trident
Part ofIndo-Pakistani War of 1971
Date 4–5 December 1971 Location Arabian Sea, 14–17 nautical miles (26–31 km; 16–20 mi) south of thePort of Karachi, Pakistan. Result Strategic Indian naval victory and partial naval blockade on Pakistan.
Belligerents
India	Pakistan
Commanders and leaders
K. P. Gopal Rao Babru Bhan Yadav	M. A. K. Lodhi
Units involved
Indian Navy	Pakistan Navy
Strength
ThreeVidyut-class missile boats TwoArnala-classanti-submarinecorvettes Onefleet tanker	Ships deployed off the coast of Karachi
Casualties and losses
None	1destroyer sunk 1minesweeper sunk 1 cargo ship sunk 1destroyer badly damaged, scrapped as result Karachi harbour fuel storage tanks destroyed 255 naval personnel killed

Operation Trident was anoffensive operation launched by theIndian Navy on Pakistan's port city ofKarachi during theIndo-Pakistani War of 1971. Operation Trident saw the first use ofanti-ship missiles in combat in the region. The operation was conducted on the night of 4–5 December and inflicted heavy damage on Pakistani vessels and facilities. While India suffered no losses, Pakistan lost aminesweeper, adestroyer, acargo vessel carryingammunition, andfuel storage tanks in Karachi. Another destroyer was also badly damaged and eventually scrapped. India celebrates itsNavy Day annually on 4 December to mark this operation. Trident was followed up byOperation Python three days later

In 1971, thePort of Karachi housed the headquarters of thePakistan Navy, and almost its entire fleet was based inKarachi Harbour. Since Karachi was also the hub of Pakistan's maritime trade, a blockade would be disastrous for Pakistan's economy. The security of Karachi Harbour was predominant to the Pakistani High Command, and it was heavily defended against any air or naval strikes. The strike aircraft based at airfields in the area secured the port's airspace.^[1]

Towards the end of 1971, there were rising tensions between India and Pakistan, and after Pakistan declared a national emergency on 23 November, theIndian Navy deployed threeVidyut-classmissile boats in the vicinity ofOkha, near Karachi, to carry out patrols. As the Pakistani fleet would also operate in the same waters, the Indian Navy set a demarcation line that ships in their fleet would not cross. Later, this deployment proved useful for gaining experience in the region's waters. On 3 December, after Pakistan attacked Indian airfields along the border, theIndo-Pakistani War of 1971 officially began.^{[2][non-primary source needed]}

While Operation Trident was primarily a naval strike, the Indian Air Force also conducted critical bombing raids on Karachi harbour facilities, oil tanks, and infrastructure. These joint efforts significantly impaired Pakistan’s maritime logistics. The humour-laced term "Karachi Halwa" was later coined informally to describe the destructive sweet mix they delivered over Karachi.^[3]

The Indian Naval Headquarters (NHQ) in Delhi, along with theWestern Naval Command, planned to attack the Port of Karachi. A strike group under Western Naval Command was formed for this mission. This strike group was to be based around the threeVidyut-class missile boats already deployed off the coast ofOkha. However, these boats had limited operational and radar range, and to overcome this difficulty, it was decided to assign support vessels to the group.^[4]

On 4 December, what was now designated as the Karachi Strike Group was formed and consisted of the threeVidyut-class missile boats:INS Nipat,INSNirghat andINS Veer, each armed with four Soviet-madeSS-N-2B Styxsurface-to-surface missiles with a range of 40 nautical miles (74 km; 46 mi), twoArnala-classanti-submarinecorvettes:INS Kiltan andINS Katchall, and afleet tanker,INSPoshak. The group was under the command ofCommanderBabru Bhan Yadav, the commanding officer of the25th Missile Boat Squadron.^[4][5][6]

As planned, on 4 December, the strike group reached 250 nautical miles (460 km; 290 mi) (nmi) south off the coast of Karachi and maintained its position during the day, outside the surveillance range of thePakistan Air Force. As Pakistani aircraft did not possessnight-bombing capabilities, it was planned that the attack would take place between dusk and dawn.^[5] At 10.30 pmPakistan Standard Time (PKT), the Indian task group moved 180 nmi (330 km; 210 mi) from its position towards the south of Karachi. Soon, Pakistani targets, identified as warships, were detected 70 nmi (130 km; 81 mi) to the northwest and northeast of the Indian warships.^[4]

INSNirghat sailed forward in a northwesterly direction and fired its first Styx missile atPNS Khaibar, a PakistaniBattle-class destroyer.Khaibar, assuming it was a missile from Indian aircraft, engaged itsanti-aircraft systems. The missile hit the right side of the ship, exploding below the galley in the electrician's mess deck at 10.45 pm (PKT). This led to an explosion in the first boiler room. Subsequently, the ship lost propulsion and was flooded with smoke. An emergency signal that read: "Enemy aircraft attacked in position 020 FF 20. No. 1 boiler hit. Ship stopped", was sent toPakistan Naval Headquarters (PNHQ). Due to the chaos created by the explosion, the signal contained the wrong coordinates of the ship's position. This delayed rescue teams from reaching its location. Observing that the ship was still afloat,Nirghat fired its second missile, hittingKhaibar in the second boiler room on the ship's starboard side, eventually sinking the ship^[4] and killing 222 sailors.^[7]

After verifying two targets in the area northwest of Karachi, at 11.00 pm (PKT), INSNipat fired two Styx missiles – one each at cargo vessel MVVenus Challenger and its escortPNS Shah Jahan, aC-class destroyer.Venus Challenger, carrying ammunition for the Pakistani forces, exploded immediately after the missile hit and eventually sank 23 nmi (43 km; 26 mi) south of Karachi. The other missile targetedShah Jahan and damaged the ship very badly. At 11.20 pm (PKT),PNS Muhafiz, anAdjutant-classminesweeper, was targeted byINSVeer. A missile was fired, andMuhafiz was struck on the left side, behind the bridge.^[4] It sank immediately before it could send a signal to the PNHQ,^[4] killing 33 sailors.^[7]

Meanwhile, INSNipat continued towards Karachi and targeted the Kemari oil storage tanks, placing itself 14 nmi (26 km; 16 mi) south of theKarachi Harbour. Two missiles were launched; one misfired, but the other hit the oil tanks, which burned and were destroyed completely, causing a Pakistani fuel shortage. The task force returned to the nearest Indian ports.^[4]

Soon, the PNHQ deployed rescue teams on patrol vessels to recover the survivors ofKhaibar. AsMuhafiz sank before it could transmit a distress call, the Pakistanis only learned of its fate from its few survivors who were recovered when a patrol vessel steered towards the ship's burning flotsam.^[4]

The Pakistan Air Force retaliated for these attacks by bombingOkha Port, scoring direct hits on fuelling facilities for missile boats, an ammunition dump, and the missile boats' jetty.^[8] The Indian Navy anticipated this attack and had already moved the missile boats to other locations to prevent any losses. However, the destruction of a special fuel tank prevented further incursions untilOperation Python, executed three days later.^[9]

As a result of the operation, the Pakistan Armed Forces were put on high alert. The deployments raised several false alarms in the ensuing days about the presence of Indian Navy vessels off Karachi. One such false alarm was raised by a Pakistan NavyFokker Friendship reconnaissance aircraft on 6 December 1971, which incorrectly reported a frigate of the Pakistan Navy as an Indian Navy missile boat. The PNHQ requested a Pakistan Air Force air strike on the supposed Indian ship. At 06.45 am (PKT), fighter jets were scrambled and strafed the vessel before it was identified as the frigatePNS Zulfiqar. Thisfriendly fire incident resulted in casualties and damage to the vessel.^[10]

With no casualties on the Indian side, this operation was a great success. To mark its victory, the Indian Navy annually celebratesNavy Day on 4 December.^[1]

Several Indian Navy personnel were honoured with gallantry awards for the operation. Then Fleet Operations Officer,Captain (laterVice Admiral)Gulab Mohanlal Hiranandani, was awarded theNau Sena Medal for the detailed operational planning; theMaha Vir Chakra was awarded to the strike group commander, CdrBabru Bhan Yadav, for planning and leading the task force; andVir Chakras were awarded toLieutenant Commanders Bahadur Nariman Kavina, Inderjit Sharma, M O Thomachan and Om Prakash Mehta, the commanding officers of INSNipat, INSNirghat, and INSVeer respectively. Master Chief M. N. Sangal of INSNirghat was also awarded theVir Chakra.^[1]LieutenantPhool Kumar Puri,Engineering OfficerINS Veer, was awarded theNau Sena Medal for his efforts in the 1971 war.^[11]

• INS Khukri
• Indo-Pakistani War of 1971
• Operation Searchlight
• Indo-Pakistani wars and conflicts
• Indo-Pakistani Naval War of 1971
• List of ships sunk by missiles

• Military operations of the Indo-Pakistani war of 1971
• Naval battles of Indo-Pakistani wars
• 20th century in Karachi
• Military history of Karachi
• Port of Karachi

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