[38] After being commissioned at the Portsmouth Navy Yard on 31 March 1945, Diablo arrived at Pearl Harbor from New London, Connecticut on 21 July and sailed on her first war patrol on 10 August with instructions to stop at Saipan for final orders.

[2] From 23 August to 2 October 1947, she joined the submarines Cutlass and Conger for a simulated war patrol down the west coast of South America and around Tierra del Fuego.

Diablo sailed to Key West, Florida, for antisubmarine warfare exercises, from 16 November to 9 December 1947, and operated from New Orleans, Louisiana, for the training of naval reservists in March 1948.

[35] Between February and April 1959, she cruised through the Panama Canal along the coasts of Colombia, Ecuador, Peru, and Chile for exercises with South American navies.

Anwar that launched a naval artillery battery on the Indian Air Force's radar station in Dwarka, Gujarat, India.

[3] On 17 September 1965 Ghazi made a surface contact and identified INS Brahmaputra and fired three World War II-era Mark 14 torpedoes and increased depth to evade counterattack.

[3] According to submarine war logs three distinct explosions were heard at about the time when the torpedoes should have impacted but Brahmaputra was not sunk, neither had it been hit since the warship did not release depth charges nor had it detected the Sonar Emissions of the Ghazi.

[3] Upon her return she won ten war awards including two decorations of Sitara-e-Jurat, one Tamgha-i-Jurat and the President's citations and six Imtiazi Sanads while her commander, Cdr.

[3] After the war in 1965–66 an arms embargo was placed on both India and Pakistan, but was later waived by the United States, strictly based on the cash and carry method as Ghazi badly needing refitting.

[6] During her submerged circumnavigation voyage she briefly stopped at Mombasa, Kenya for refueling and, in Maputo, Mozambique before making a farewell visit at Simon's Town, South Africa.

[6] Her final stopover was at İzmir in Turkey and she continued submerged through the east coast of the Sea of Marmara to dock at the Gölcük Naval Shipyard, which was the only facility to upgrade the Tench-class based computers and other electromechanical equipment.

[3][41] Ghazi was on a two-fold mission: the primary goal was to locate and sink Vikrant and secondary was to mine India's eastern seaboard, which was to be fulfilled irrespective of the accomplishment of the first.

[45] The mysterious sinking of Ghazi took place on 4 December 1971 during its hunt to find Vikrant and/or during the minelaying mission on the Visakhapatnam Port, Bay of Bengal.

: 82 [46][47] Unable to detect her target, PNS Ghazi's commanders became disillusioned about their hunt for Vikrant and turned back to Visakhapatnam to start laying mines off the harbour with a confidence that it would take a swipe at INS Vikrant or at least bottle up the Indian Navy's heavy units clustered in this major Indian naval base on the night of 2–3 December 1971.

According to the Indian Navy's claims, Captain Singh changed the course at full speed across the specified point and ordered to drop two depth charges, which was done.

[48][49] On the night of 4–5 December 1971, Ghazi sank with all 93 servicemen on board (11 officers and 82 enlisted[50]) under mysterious circumstances: 157 [44][51] off the Visakhapatnam coast, allowing the Indian Navy to effect a naval blockade of East Pakistan.

: 157 [51] According to Indian DNI's director Rear-Admiral Mihir K. Roy, Ghazi's existence was revealed when a signal addressed to naval authorities in Chittagong was intercepted, requesting information on a lubrication oil only used by submarines and minesweepers.

[5] Vice Admiral Nilakanta Krishnan of the Eastern Naval Command had maintained that it was clear that Pakistan would have deployed Ghazi in the Bay of Bengal and a part of its plan was an attempt to sink the Indian aircraft carrier Vikrant.

[53] The Navy NHQ repeatedly made frantic efforts to establish the communication and anxiety grew as days passed for her return to the base.

[53] The Indian NHQ issued the statement a few hours before the loss of INS Khukri, and prior to launch of second missile attack on Karachi port.

[53] After the ceasefire in 1971, the Government of India undertook an investigation into the incident and immediately claimed that the submarine was sunk following the series of manoeuvres by the Indian Navy.

[53] A submarine rescue vessel, INS Karanj was sent to check the debris and India later built a "Victory at Sea Memorial" on the coast near where Ghazi was sunk.

The book also noted that the time of dropping of the charges, the explosion which was heard by the people of Visakhapatnam and that of a clock recovered from Ghazi, matched.

[27] Admiral Roy of India stated: "The theories propounded earlier by some who were unaware of the ruse de guerre (attempt to fool the enemy in wartime) leading to the sinking of the first submarine in the Indian Ocean gave rise to smirks from within our own (Indian) naval service for an operation which instead merited a Bravo Zulu (flag hoist for Well Done)".

[52] Admiral S. M. Nanda, Chief of Naval Staff of the Indian Navy during the conflict, stated : "In narrow channels, ships, during an emergency or war, always throw depth charges around them to deter submarines.

[63] It was only on 10 February 1972, when the incident was officially recognised by the Government of Pakistan and then-President Zulfikar Bhutto met with the grieving families and loved ones of the officers and sailors who served in Ghazi, and told them that they may have all perished due to this incident as many of the slain family members were pushing for repatriation to the Government of Pakistan as they were keeping the hope alive that they may have survived and rescued by India.

[3] Pakistan never accepted the theory from the Indian Navy but provided its alternative insights into this disaster based on the investigations on the Mark 14 torpedoes and other vintage military equipment installed in Ghazi.

[53] Credibility is added to this story by the later discovery made by Indian Coast Guard divers in 2003, that the damaged parts of the submarine had been blown inside out.

[48][67] From information found in the investigation conducted on the cause of the loss of the American submarine USS Cochino, it is possible that the lead-acid battery vented explosive hydrogen gas while charging underwater.

Items recovered were the back-up tapes of the radar computers, war logs, broken windshield, top secret files, as well as one of the bodies of a petty officer mechanical engineer (POME) who had a wheel spanner tightly grasped in his fist.