Navy Day India: Operation Trident and the 1971 Karachi Raid
Why India marks Navy Day on 4 December: Operation Trident, the 1971 missile-boat raid that sank Pakistani ships off Karachi. Timeline to Navy Day 2026.
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At about 10.40 pm on 4 December 1971, a Soviet-built Indian missile boat fired the first anti-ship missile ever used in the region at a Pakistani destroyer south of Karachi. By midnight two warships and a cargo ship were sinking, another destroyer was wrecked and Karachi’s oil tanks were burning, and not one Indian sailor had been hurt. Navy Day in India is celebrated every 4 December to mark that raid, Operation Trident. This timeline follows it from the crisis of 1971, through the second raid four nights later and the loss of INS Khukri, to how the day is marked in 2026.
💡 Short Answer
India celebrates Navy Day on 4 December because on the night of 4–5 December 1971 the Navy carried out Operation Trident. Missile boats INS Nirghat, INS Nipat and INS Veer sank the destroyer PNS Khaibar, the minesweeper PNS Muhafiz and the ship Venus Challenger, wrecked PNS Shah Jahan and set Karachi’s Keamari oil tanks on fire, with no Indian losses.
Navy Day and Operation Trident: Key Questions
Operation Trident and Navy Day in Ten Points
- Why 4 December: Navy Day marks the Karachi raid of 4–5 December 1971.
- Small boats, big punch: three Osa-class boats, each with four Styx missiles, did the striking.
- Night was the shield: most Pakistani aircraft could not attack at night.
- First missile at about 10.40 pm: INS Nirghat sank PNS Khaibar.
- Three ships sunk, one wrecked: Khaibar, Muhafiz and Venus Challenger; Shah Jahan was scrapped.
- Karachi’s fuel burned: Nipat hit the Keamari oil tanks at about midnight.
- Python four nights later: INS Vinash hit the oil farm again and sank two merchant ships.
- A heavy loss elsewhere: INS Khukri was sunk off Diu the same night as Python, with 194 killed.
- Navy Day has moved to the coast: demonstrations since 2022 have rotated between cities.
- Karachi still matters: in May 2025 the Navy said it had been ready to strike it again.
Navy Day and the 1971 Raids at a Glance
The key dates. Scroll sideways on a phone.
| Date | Event |
|---|---|
| 3 Dec 1971 | Pakistan’s air strikes on Indian airfields, including Okha; war widens |
| 3–4 Dec 1971 | Submarine PNS Ghazi sinks off Visakhapatnam |
| 4–5 Dec 1971 | Operation Trident: Khaibar, Muhafiz and Venus Challenger sunk, Shah Jahan wrecked, Keamari oil tanks hit |
| 8–9 Dec 1971 | Operation Python: Gulf Star and Harmattan sunk, PNS Dacca wrecked, oil farm hit |
| 8–9 Dec 1971 | INS Khukri sunk by PNS Hangor off Diu; 194 killed |
| 16 Dec 1971 | Surrender in Dhaka; Bangladesh is born |
| Every 4 Dec | Navy Day marks Operation Trident |
| 8 Dec 2021 | President’s Standard for the 22nd Missile Vessel Squadron, the ‘Killers’ |
| 2022–2025 | Navy Day demonstrations at Visakhapatnam, Sindhudurg, Puri and Thiruvananthapuram |
| May 2025 | Operation Sindoor: Navy ready to strike ‘including Karachi’ |
| 18 Feb 2026 | International Fleet Review off Visakhapatnam |
| 31 May 2026 | Admiral Krishna Swaminathan becomes Navy chief |
| 4 Dec 2026 | Navy Day, 55th anniversary of Trident |
The Timeline: From the 1971 Crisis to Navy Day 2026
Newest first. Tags mark the war, Trident, Python, the loss of INS Khukri, memory, Navy Day events and 2025–26 developments.
2026
Navy Day turns 55 Navy Day
The 2026 Navy Day will be the first under Admiral Krishna Swaminathan. Since 2022 the main operational demonstration has moved to a different coastal city each year; we had not found an official announcement for 2026 at the time of writing.
2026
INS Samarthak commissioned at Karwar 2025–26
The 107-metre, roughly 3,700-tonne ship can serve as a weapons-trials platform, support mine countermeasures and act as a mothership for uncrewed aerial, surface and underwater systems. Missile boats in 1971 needed tankers and escorts to reach Karachi; the new generation of support ships is built around drones and sensors.
2026
Admiral Krishna Swaminathan becomes Navy chief 2025–26
A communication and electronic-warfare specialist commissioned in 1987, Swaminathan once commanded the missile vessels INS Vidyut and INS Vinash. Vidyut was the class name of the 1971 Osa boats, and the first INS Vinash fired the missiles of Operation Python. He came to the top job from Mumbai’s Western Naval Command, the command that ran the Karachi raids.
2026
International Fleet Review off Visakhapatnam 2025–26
India’s third International Fleet Review, after Mumbai in 2001 and Visakhapatnam in 2016, brought 60 Indian Navy ships, 19 foreign warships, three Indian submarines and more than 60 aircraft. It took place in the city whose Victory at Sea memorial honours the 1971 war.
2025
Navy Day demonstration in Thiruvananthapuram Navy Day
President Droupadi Murmu watched the first Navy Day operational demonstration held in Kerala’s capital, a day before Navy Day itself. Kerala’s Governor and Chief Minister attended.
Karachi in the sights again 2025–26
After the Pahalgam attack of 22 April 2025, the Navy put its carrier battle group, submarines and aircraft to sea and carried out missile firings within 96 hours. Vice Admiral A.N. Pramod, Director General of Naval Operations, said the forces had been ready to strike targets at sea and on land, ‘including Karachi’, at a time of India’s choosing, and that Pakistani ships had been kept in harbour or close to their coast. No naval strike was ordered before the ceasefire of 10 May.
2024
Navy Day at Puri’s Blue Flag beach Navy Day
The third demonstration outside Delhi moved to the east coast, with warships, aircraft and marine commandos off Puri.
2023
Navy Day at Sindhudurg Navy Day
The demonstration was held off Tarkarli near Sindhudurg fort, linking Navy Day with the maritime legacy of Chhatrapati Shivaji Maharaj, whose navy built the fort in the 17th century.
2022
Navy Day leaves Delhi for the coast Navy Day
For the first time the main Navy Day celebrations were held outside the national capital, as a public operational demonstration in Visakhapatnam, home of the Eastern Naval Command.
2021
President’s Standard for the ‘Killers’ Memory
The squadron that traces its lineage to the boats of Trident and Python received the President’s Standard, the honour given to formations smaller than those receiving the President’s Colour. It then included the missile vessels Prabal, Pralaya, Nashak, Nishank, Vipul, Vibhuti, Vinash and Vidyut.
2018
The names sail on, then retire Memory
The 1971 Osa boats had long gone, but their names had been given to a newer generation of missile vessels. The second Nirghat, commissioned around 1990, was decommissioned with Nirbhik at Naval Dockyard, Mumbai.
1971
Surrender in Dhaka The war
The war ended with the creation of Bangladesh. At sea, the Western Fleet had dominated the Arabian Sea after the Karachi raids, while the aircraft carrier INS Vikrant’s aircraft struck ports in East Pakistan.
1971
INS Khukri is lost off Diu Loss
On the same night as Operation Python, the anti-submarine frigate Khukri was hit by two torpedoes while hunting a submarine off the Gujarat coast. It is the only warship the Indian Navy has lost in war since independence. Captain Mahendra Nath Mulla was awarded the Maha Vir Chakra posthumously; a memorial stands at Diu.
1971
Operation Python: Karachi again Python
A smaller force returned to Karachi. INS Vinash, under Lieutenant Commander Vijay Jerath, fired all four of its missiles: one hit the Keamari oil farm, others sank the Panamanian vessel Gulf Star and the British merchant ship Harmattan and damaged the Pakistani fleet tanker PNS Dacca beyond repair. The raid had been delayed in part because Pakistani air attacks had destroyed a fuel tank at Okha. No Indian ship was hit.
1971
The strike group is back in Bombay Trident
The ships came back in ones and twos. A communication fade meant the task group commander in INS Kiltan never got the withdrawal order and reached a point 20 miles south of Karachi to find himself alone; INS Veer, slowed by a machinery fault, made repairs and followed.
1971, ~00:00
Keamari’s oil tanks burn Trident
With no ships left in the outer anchorage, Commander Yadav ordered Nipat to fire at a shore target. Its missile hit the oil tanks at Keamari at about midnight. The fires in Karachi’s fuel installations became the defining image of the raid.
1971, night
PNS Muhafiz sinks Trident
A third radar contact to the north was engaged by Veer. The ship burned fiercely for over 70 minutes before sinking. She turned out to be the coastal minesweeper PNS Muhafiz, and about 33 of her crew were killed. Pakistan’s naval headquarters learnt of her loss only when survivors were found by a boat searching for Khaibar’s crew.
1971, night
Venus Challenger and Shah Jahan hit Trident
Nipat engaged the contact to the north-east. The merchant ship MV Venus Challenger, carrying ammunition for Pakistan, was hit and sank; the destroyer PNS Shah Jahan was badly damaged and later scrapped. Accounts differ on exactly which missile struck which ship, but both were put out of action.
1971, 22:40
First missile: PNS Khaibar Trident
At about 10.30 pm the boats, running at 32 knots about 70 nautical miles south of Karachi, detected targets 43 miles to the north-west and north-east. The destroyer Khaibar turned to intercept. At about 10.40 pm Nirghat fired. The first missile hit the boiler room; the second stopped her. Khaibar sank in about 45 minutes, and about 222 of her crew died.
1971, day
The run-in to Karachi Trident
The force waited about 250 nautical miles south of Karachi during daylight, out of reach of Pakistani aircraft, then raced north after dark. The missile boats had short range, so the corvettes were there to provide radar, communications and, if needed, a tow or fuel. A fourth missile boat stayed on patrol off Dwarka to cover the return.
1971
Pakistan’s air strikes widen the war The war
The Navy had planned to hit Karachi on the same night that Pakistan opened hostilities in the west, but the boats could not reach the launch point 150 miles from Karachi in time. The attack was set for the next night. In the Bay of Bengal, the submarine PNS Ghazi sank off Visakhapatnam around the turn of 3–4 December.
1971
A new commander for the ‘Killers’ The war
An anti-submarine specialist with a year’s experience on missile boats, Yadav was given command a day before the war began. He would lead Trident from INS Nipat.
Missile boats arrive from the Soviet Union The war
The small boats had limited range and were meant for harbour defence. Indian planners, including Captain G.M. Hiranandani, worked out how to tow or escort them into the Arabian Sea and use them offensively, a concept that was tested for the first time over Karachi.
1971
The crisis in East Pakistan The war
After the Awami League won the December 1970 election, Pakistan’s army began a crackdown in East Pakistan. Refugees poured into India, and by late 1971 war was widely expected.
The Night of the Raid, Hour by Hour
How quickly it happened.
Pick an Indian ship to see its role in the 1971 Karachi raids and what it achieved.
Six ships sailed for Trident and three for Python. Not one was hit off Karachi. The Navy’s only loss of the war came elsewhere, off Diu.
What Pakistan Lost Off Karachi
Ships and installations hit in Operations Trident and Python.
| Ship | Type | Hit by | Result |
|---|---|---|---|
| PNS Khaibar | Destroyer | INS Nirghat, Trident | Sunk; about 222 killed |
| PNS Muhafiz | Coastal minesweeper | INS Veer, Trident | Sunk; about 33 killed |
| MV Venus Challenger | Merchant ship with ammunition | INS Nipat, Trident | Sunk |
| PNS Shah Jahan | Destroyer | Trident missile strike | Badly damaged, later scrapped |
| Keamari oil tanks | Shore fuel installations | INS Nipat (Trident), INS Vinash (Python) | Set ablaze twice |
| SS Gulf Star | Panamanian merchant ship | INS Vinash, Python | Sunk |
| SS Harmattan | British merchant ship | INS Vinash, Python | Sunk |
| PNS Dacca | Fleet tanker | INS Vinash, Python | Damaged beyond repair |
Casualty figures for the Pakistani ships come from later accounts and vary slightly between sources. The exact share of Karachi’s fuel stocks destroyed is not reliably documented in the sources we used.
Why Operation Trident Worked
The right weapon in an unexpected role. The Osa boats had been bought for coastal defence and had little range or air defence. The Navy’s planners turned that around: corvettes would escort them, a tanker would refuel them and they would be towed or shepherded to within striking distance, then sprint in at 32 knots. Each boat’s four Styx missiles could hit a destroyer from well beyond its guns.
Darkness and timing. The force waited out of air range during the day and attacked at night, when most Pakistani aircraft could not respond. Pakistan’s own warning to merchant ships to stay 70 miles out after sunset meant that any contact inside that ring was almost certainly a warship.
Surprise and confusion. Khaibar did not grasp that an attack was coming until about 10.15 pm. Pakistan’s naval headquarters did not learn that Muhafiz had sunk until her survivors were picked up. By then the boats were heading home.
Luck played a part. A communications fade left the task group commander unaware of the order to withdraw, and INS Veer had to slow down with a machinery fault on the way back. Neither was exploited.
What the Popular Story Gets Slightly Wrong
Common phrasings checked against the records we used.
| Popular claim | What the record shows |
|---|---|
| The raid was on Karachi Harbour itself | Ships were hit at sea, 19 to 35 miles south of Karachi; only the oil tanks ashore were inside the port area |
| Nipat attacked Shah Jahan and Venus Challenger | Most accounts agree; the USI account credits Nipat with Venus Challenger and Veer with a second double target, so details vary |
| India lost no ships in 1971 | True of the Karachi raids, but INS Khukri was sunk off Diu on 8–9 December |
| Navy Day is held only in Delhi | Since 2022 the main demonstration has moved to a different coastal city each year |
| Year | Navy Day demonstration | Chief guest |
|---|---|---|
| 2022 | RK Beach, Visakhapatnam, Andhra Pradesh, first outside Delhi | President Droupadi Murmu |
| 2023 | Tarkarli, Sindhudurg, Maharashtra | Prime Minister Narendra Modi |
| 2024 | Blue Flag beach, Puri, Odisha | President Droupadi Murmu |
| 2025 | Shangumugham beach, Thiruvananthapuram, Kerala (3 December) | President Droupadi Murmu |
| 2026 | Not announced as of 18 October 2026 | – |
Beyond the main demonstration, ships open to the public, commands hold ‘Beating Retreat’ ceremonies and wreaths are laid at war memorials such as Victory at Sea in Visakhapatnam and the INS Khukri memorial at Diu. The day is also used to show the Navy’s peacetime work: anti-piracy patrols, humanitarian assistance and disaster relief, and evacuation of Indians from conflict zones.
Pick a measure to compare the Navy of Operation Trident with today’s.
A short comparison, not a full order of battle.
Navy Day in 2026: Karachi, Carriers and a Fleet Review
The 55th Navy Day arrives in an eventful year. In February the Navy hosted its largest International Fleet Review, with 85 ships from 74 countries off Visakhapatnam. In May Admiral Krishna Swaminathan, a former missile-vessel captain, took command. In October the Navy commissioned INS Samarthak, a mothership for drones and uncrewed vessels. And Operation Sindoor in 2025 showed that the Arabian Sea and Karachi remain at the centre of India’s naval planning against Pakistan, though this time the fleet’s role was to deter rather than strike.
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Conclusion: The Night That Gave the Navy Its Day
Operation Trident lasted about an hour and a half. It sank or wrecked four ships, set Karachi’s fuel ablaze, cost India nothing and, with Python four nights later, pushed Pakistan’s navy into its harbour for the rest of the war. That is why 4 December, rather than the date of any bigger battle, became Navy Day.
Fifty-five years on, the boats and missiles have changed completely, but the lesson the Navy draws from that night has not: preparation, surprise and the reach to strike from the sea.
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⚠️ Editorial Note
This timeline draws on the United Service Institution of India’s account of Operation Trident, which uses Vice Admiral G.M. Hiranandani’s official history Transition to Triumph (2000); the President’s address on the Standard for the 22nd Missile Vessel Squadron (PIB, 2021); reporting on Navy Day 2025, Operation Sindoor, the International Fleet Review 2026, the change of Navy chief and INS Samarthak; and published summaries of Operations Trident and Python. Times are approximate and in Pakistan Standard Time. Pakistani casualty figures vary between sources. Accounts differ on some details of which missile struck which ship. This article is historical and does not take a side in present-day India–Pakistan relations.
Sources & further reading
Every dated entry above was checked against these references. Last reviewed 18 October 2026.
- Operation Trident: A Triumph of the Indian Navy in the 1971 Indo-Pak War
- Address by President Ram Nath Kovind on presenting the President's Standard to the 22nd Missile Vessel Squadron
- Navy showcases maritime prowess, multi-domain combat capabilities off Kerala coast
- Operation Sindoor: Indian Navy was ready to strike Karachi, says Vice Admiral Pramod
- President of India witnesses International Fleet Review at Visakhapatnam
- Admiral Krishna Swaminathan assumes charge as 27th Chief of the Naval Staff
- Indian Navy commissions first multi-purpose vessel, INS Samarthak
- INS Khukri (F149): sinks with the captain and his men in 1971
- Operation Trident (1971)
- Operation Python