Indo-Pakistani naval warfare of 1971
Part of Indo-Pakistani war of 1971 and Bangladesh Liberation War
Date 2–16 December 1971 Location East-Pakistan (now Bangladesh) Result Pakistan Naval failure Indian Decisive Victory Eastern Front Defeat of Pakistan naval forces Pakistani naval forces surrender Western Front West Pakistan Sea ports were severely damaged ceasefire and negotiated Territorial changes East-Pakistan became Bangladesh
Belligerents
Pakistan Pakistan Navy	India  Indian Navy
Commanders and leaders
Vice Admiral Muzaffar Hassan Rear-Admiral Hasan Ahmed Rear-Admiral M. Shariff	Admiral S. M. Nanda Vice-Admiral S.N. Kohli Vice-Admiral R. Krishna
Casualties and losses
1,900 Killed in action † 1,413 captured  (POW) 7 gunboats 1 minesweeper 1 submarine 2 destroyers 3 patrol crafts	194 Killed in Action † 1 ASW Frigate

The Indo-Pakistani Naval warfare of 1971 were the series of aggressive naval battles fought by the Indian and Pakistani Navy during the Indo-Pakistani War of 1971. These battles were an integral part of India-Pakistan War of 1971 and the Pakistan war in Bangladesh. The series of naval operations began by the Indian Navy to exert pressure from seaward as the Indian Army and Indian Air Force moved in to close the ring round East Pakistan from several directions on land. The naval operations incorporated the naval interdiction, air defence, ground support, and logistics missions led successfully by the Indian Navy. After the success of East-Pakistan naval operations, the Indian navy later increased the diameter of their naval operations to West Pakistan.

With the successful outcomes of Indian Navy's naval operations in East-Pakistan, the Indian Navy commenced the large scale of naval operations, Operation Trident and Operation Python in the Western front, prior to the start of formal combat between India and Pakistan.

Background

The Indian Navy did not play a vital and integral role during the Indo-Pakistani War of 1965 as the war was more focused on the land based conflict. On September 7, a flotilla of the Pakistan Navy under the command of Commodore S.M. Shaikh, carried out a small scale bombardment of the Indian Navy's radar station of Dwarka, which was 200 miles (300 km) south of the Pakistani port of Karachi. Having known as Operation Dwarka, the operation did not score any big hits^[1]. The operation was failed to achieve any major and primary objectives of disabling the radar station and there was no immediate retaliatory response from India.

After the war, the Indian Navy underwent rapid modernization and expansion. Consequently, the Indian Navy budget grew from Rs. 35 crores to रRs. 115 crores^[2]. The Indian Navy's Combatant Fleet was augmented by addition of Submarine squadron and acquisition of six Osa missile ship from the Soviet Union. The Indian Naval Air Arm was also strengthened^[3]. As the crises between East and West-Pakistan began, the Indian Armed Forces intervened, hence, starting the Bangladesh Liberation War.

Pakistani Eastern Naval Command

The Pakistan Combatant Forces' GHQ had declined substantial naval contingent for the defense of East Pakistan. The Pakistan Naval forces's had inadequate ships to challenge the Indian Navy on both front, and the PAF was unable to protect this ships from both Indian Air Force and the Indian Naval Air Arm. The Pakistan Navy had deployed all her from naval power in Western Front to counter the Indian challenge.

The East Pakistan's naval ports were left defenseless as the Eastern Military Command of Pakistan had decided to fight the war without the navy and faced with a hopeless task against overwhelming odds, the navy planned to remain in the ports when war broke out^[4].

In eastern wing, the Pakistan Navy had heavily depended on her Gun boat squadron^[5]. The Pakistan's Eastern Naval Command was commanded by Flag Officer Commanding (FOC) Rear-Admiral Mohammad Shariff who also served as the right-hand of Lieutenant-General Niazi. The Pakistan Navy had 4 (PNS Jessore, Rajshahi, Comilla, and Sylhet). The boats were capable of attaining maximum speed of 20 knots (37 km/h), were crewed by 29 sailors. Having known as Pakistan Navy's brown water navy, the gun boats were equipped with various weapons, including heavy machine guns. The boats were adequate for patrolling and led anti-insurgency operations. But they were hopelessly out of place in a conventional warfare^[6].

In the early of April, Pakistan Navy began the naval operations around the East-Pakistan to support the Army's executed Operation Searchlight. The Rear-Admiral Mohammad Shariff, Flag Officer Commanding (FOC) of Pakistan's Eastern Naval Command had coordinated all these projected missions. On April 26, Pakistan Navy had successfully completed the Operation Barisal, but it resulted in temporary occupation of city of Barisal^[7].

The bloody ubran guerrilla warfare was insued, and Operation Jackpot had severely damaged the operational capability of Pakistan Navy. Before the starting of the hostilities, all the naval gun boats were stationed at the Chittagong^[8]. As the Air operations were began, the IAF aircraft damaged the Rajshahi, while Comilla sunk on 4th December. On December 5th, the IAF sank two patrol boats in Khulna. The PNS Sylhet was destroyed on December 6 and the Balaghat on December 9 by Indian aircraft. On 11th December, the PNS Jessore was destroyed, while Rajshahi was repaied. Rajashahi under the command of Lieutenant-Commander Shikder Hayat managed to evade the Indian blockade and reach Malaysia before the surrender on December 16.

Naval Operations in Eastern Front

The Indian Navy's Eastern Naval Command had effectively applied a naval blockade which also completely isolated East-Pakistan's Bay of Bengal, trapping the Eastern Pakistani Navy and eight foreign merchant ships in their ports.

On December 4th of 1971, the INS Vikrant, the aircraft carrier, was also deployed in which its Sea Hawk attack aircraft contributed in Air Operations in East Pakistan. The aircraft successfully attacked many coastal towns in East Pakistan including Chittagong and Cox's Bazaar. The continuous attacks later dismantle the PAF's capability to retaliate^[9].

The Pakistan Navy quickly responded by deploying her long range submarine, PNS Ghazi, to counter the threat. The PNS Ghazi, under the command of Cdr Zafar Muhammad Khan^[10], was assumed to locate the INS Vikrant, but when it was not able to locate, decided to mine the port of Vishakapatnam – the Headquarter of Eastern Naval Command^[11]. The Indian Navy's Naval Intelligence laid a trap to sink the submarine by dispatching INS Rajput, the destroyer. At around midnight of 3–4 December, the PNS Ghazi began its operation of laying mines. At same time, INS Rajput started to moving out from her garrison and began her mission to East-Pakistan.

The INS Rajput's sonar radar reported the disturbance underwater and two of the depth charges were released^[12]. The submarine sank with all 92 on hands due to indirect or direct impact of the depth charges, around midnight on 3 December 1971 off the Vishakapatnam coast^[13].

The sinking of Ghazi turned out to be a major blow and sat back for Pakistan Naval operations in East-Pakistan^[14]. It diminished the possibilities of carry out the large scale of Pakistan naval operations in Bay of Bengal. It also eliminated further threat possessed by Pakistan Navy to Indian Eastern Naval Command.

The successful Indian Air Operations and Operation Jackpot, led by the Bengali units, had undermine the operational capability of Pakistan Navy. Many officers had defected from the Navy and fought against the Pakistan Navy^[15]. By the time Pakistan Defences Forces surrendered, the Navy had suffered the most damages as almost all of the gun boats, destroyer (PNS Sylhet), and submarine was lost in the conflict, including their officers.

Sinking of INS Khurki

As the Indian military offensive in East Pakistan increases, the Pakistan Navy had dispatched her submarine squadron on both front. Codename Operation Falcon, the Pakistan Navy had deployed PNS Hangor, a Daphné class submarine, near the coastal water of West-Pakistan.

According to the Lieutenant R. Qadri, an Electrical engineer officer at Hangor during the time, the assigned mission was considered quite difficult and highly dangerous, with the submarine squadron sailing under the assumption that the dangerous nature of this mission meant a great mortal risk to the submarine and her crew^[16].

On the midnight of 21st November of 1971, PNS Hangor, under the command of Commander Ahmed Tasnim, began her reconnaissance operations. Both PNS Ghazi and PNS Hangor maintained coordination and communication throughout patrol operations.

On December 2nd and 3rd December, Hangor had detected alarge formation of ships from Indian Navy's Western fleet which included cruiser INS Mysore. Hangor had passed an intelligence to Pakistani naval forces of a possible attack by the observed Indian Armada near Karachi. The Indian Naval Intelligence intercepted these transmittions, and dispatched two ASW frigates, INS Khukri and the " INS Kirpan of 14th Squadron - Western Naval Command.

On 9th December of 1971, at 1957 hours, Hangor sunk INS Khurki with two homing torpedoes. According to her commander, the frigate sank within the matter of two minutes^[17]. The frigate sank with 192 hands on board. Hangor also had struck INS Kirpan with two torpedoes (fired in two different occasions), but the torpedoes had missed its target^[18]. Kirpan quickly disengaged the engagement as she had fled the battle and successfully evaded the fired torpedoes.

Attack on Karachi

On 4th December, the Indian Navy, equipped with P-15 Termit, launched Operation Trident on port of Karachi. During this time, Karachi had housed the Headquarters of Pakistan Navy as well as the backbone of country's economy. The Indian Navy's Pre-emptive strike resulted in an ultimate success. The Indian missile ships successfully sunk the minesweeper PNS Muhafiz and the destroyer PNS Khaibar. Operation Trident was an enormous success with no physical damage to any of the ships in the Indian task group, which the attack naval squadron safely returned back to their garrison.

The Operation Trident caused a great psychological trauma to Pakistani forces. On December 6th, a naval intelligence failure caused a confrontation between Pakistan Navy and their own Air Force. Fighter jets had mistakenly targeted PNS Zulfikar, the destroyer, before it was identified as one of their own^[19]. PNS Zulfikar was badly damaged and her crew members were badly wounded during the air raid. Soon after the raid, the PNS Zulfikar was unable to perform her active duty, leaving the West Pakistani shores and coasts defenseless.

Shortly after the attack of INS Khurki, the Indian Navy launched a second large scale operations, on the midnight of December 8 and December 9 of 1971. The operation, codename Operation Python, was commenced under the command of Chief of Naval Staff of the Indian Navy Admiral S.M. Nanda^[20]. The INS Vinash, the missile boat, and two multipurpose frigates, INS Talwar and INS Trishul participated in the operation. The attack squadron approached Karachi and fired four missiles. During the raid, the Panamian vessel Gulf Star, Pakistan Navy's PNS Dacca, the destroyer, and the British ship SS Harmattan were badly damage. More than 50% of total fuel requirement for the Karachi was blown^[21]. More than $3 billion worth of economic and social sector damage, most of the oil reserves and ammunition had been lost, warehouses and naval workshops destroyed. The PAF was also affected by the attack. The missiles had destroyed the run way for the PAF to take sworties. The Karachi port was severly damaged and was left burning. The operation further crippled the Pakistani economy, and it had also paralyzed the Pakistan naval operations in western coast.