PNS/M Ghazi (S–130) (previously USS Diablo (SS-479); reporting name: Ghazi), , was a diesel-electric submarine, the first fast-attack submarine in the Pakistan Navy. She was leased from the United States Navy in 1963.

She served in the United States Navy from 1945 to 1963 and was loaned to Pakistan under the Security Assistance Program (SAP) on a four-year lease after the Ayub administration successfully negotiated with the Kennedy administration for its procurement. In 1964, she joined the Pakistan Navy and saw military action in the Indo-Pakistani theatres in the 1965 and, later in the 1971 wars.

In 1968 Ghazi executed a submerged circumnavigation of Africa and southern parts of Europe through the Indian Ocean to the Atlantic Ocean, due to the closure of the Suez Canal, in order to be refitted and updated at Gölcük, Turkey. The submarine could be armed with up to 28 Mk.14 torpedoes and had the capability of mine-laying added as part of her refit.

Starting as the only submarine in the Indo-Pakistani war of 1965, Ghazi remained the Pakistan Navy's flagship submarine until in 1971, when she sank under mysterious circumstances near India's eastern coast while conducting naval operations en route to the Bay of Bengal. While the Indian Navy credits Ghazis sinking to its destroyer , the Pakistani military oversights and reviews stated that "the submarine sank due to either an internal explosion or accidental detonation of mines being laid by the submarine off the Visakhapatnam harbour".Seapower: A Guide for the Twenty-first Century By Geoffrey Till

In 2010, it was revealed the Indian Navy destroyed all records of their investigations into this matter in 1980 after the Indo-Pakistani War of 1971.Warriors of the waves - Express TribuneReal story of submarine PNS Ghazi and the mystery behind its sinking - Economic TimesThe Ghazi Attack: Why did India destroy records of one of its greatest naval victories - Indian Defence News Nonetheless, Indian historians consider the sinking of Ghazi to be a notable event; as they have described the sinking as one of the "last unsolved greatest mysteries of the 1971 war." Initially made in Telugu and later due to good box office performance this movie was dubbed in several other Indian languages.

Service with United States Navy , a long-range fast-attack was launched on 1 December 1944, sponsored by the wife of U.S. Navy Captain V. D. Chapline on 31 March 1945 with Lieutenant Commander Gordon Graham Matheson as her first commanding officer.

She was the only warship of the United States Navy to be named Diablo, which means "devil" in Spanish. The submarine's assigned and issued insignia patch identified the caricature image of the devil running with a torpedo in the sea.

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. With the ceasefire, her destination was changed to Guam where she arrived on 22 August 1945. On the last day of the month, she got underway for Pearl Harbor and the East Coast arriving at New York City on 11 October, except for a visit to Charleston, South Carolina in October where she remained at New York until 8 January 1946.

From 15 January 1946 to 27 April 1949, Diablo was based in the Panama Canal Zone participating in fleet exercises and rendering services to surface units in the Caribbean Sea. From 23 August to 2 October 1947, she joined the submarines and for a simulated war patrol down the west coast of South America and around Tierra del Fuego. The three submarines called at Valparaíso, Chile, in September while homeward bound. 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.

Diablo arrived at Naval Station Norfolk in Virginia, her new home port, on 5 June 1949, and participated in Operation Convex in 1951, and alternated training cruises with duty at the Sonar School at Key West. Her homeport became New London in 1952 and she arrived there 17 September to provide training facilities for the Submarine School.

From 3 May to 1 June 1954, she was attached to the Operational Development Force at Key West for tests of new weapons and equipment. She participated in Operation Springboard in the Caribbean from 21 February to 28 March 1955, and continued to alternate service with the Submarine School with antisubmarine warfare and fleet exercises in the Caribbean and off Bermuda, as well as rendering services to the Fleet Sonar School and Operational Development Force at Key West. 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. On 27 May 1960, she entered Philadelphia Naval Shipyard for an overhaul which continued until October 1960.

In 1962 her hull classification symbol was changed to AGSS-479.

Diablo was decommissioned on 1 June 1964 and was commissioned in the Pakistani Navy the same day.

Awards Asiatic-Pacific Campaign Medal World War II Victory Medal National Defense Service Medal with star

Service with Pakistan Navy

The procurement and acquisition of Ghazi was a result of lengthy and complicated negotiation between the administrations of Pakistan and the United States. Since the 1950s the Pakistan Navy had been seeking to procure imported submarines, initially negotiating with the Royal Navy and subsequently also with the United States Navy.

With Ayub administration improving relations with the Eisenhower administration in 1960, Ghazi was finally procured under the Security Assistance Program (SAP) authorized by the Kennedy administration on a four-year lease with an option of renewing or purchasing the submarine afterwards in 1963.

Ghazi was the first submarine to be operated by a Navy in South Asia, becoming a serious threat to the Indian Navy. Contrary to popular perception, Ghazi technological feats were downgraded and extensively refitted its Fleet Snorkel under the Guppy program of the U.S. Navy at the Philadelphia Naval Dockyard, and was mostly unmodernized when she joined the services of Pakistan Navy. Naval historians had described Ghazi as an unarmed "clockwork mouse" used for training purposes. Nonetheless, the Indian Navy immediately was under the impression that it was militarized and an updated submarine that posed a serious threat.

She was fitted with 14 vintage Mark-14 torpedoes which had the controversy and notoriety of its own during World War II. On 4 September 1964 she arrived at the Naval Dockyard in Karachi and joined the Navy as its first long-range fast-attack submarine. She was named and designated as Ghazi (lit. Holiest Warrior) by the Pakistan Navy in 1964.

Western Front of the Indo-Pakistani war of 1965

On 5 August 1965 war broke out between India and Pakistan as a result of a covert infiltration in Indian Kashmir. Ghazi, was at that time under command of then-Commander Karamat Rahman Niazi, who would later ascend as a four-star admiral in the Navy. Other officers who served in Ghazi were then-Lieutenant-Commander Ahmed Tasnim (later promoted as Vice-Admiral), Sub-Lieutenant Fasih Bokhari, and Lieutenant Zafar Muhammad who would later command her, as a Commander, in 1971.

Notable Naval Officers of Ghazi in 1965 included: Cdr. K. R. Nyazi– Ofc–in–chrg. of Ghazi. Lt-Cdr. Ahmed Tasnim–2nd-in-Cmd. of Ghazi Lt-Cdr. Habib Ahmad-Electrical Officer of Ghazi Lt. Z.M. Khan– Chief Navigation officer in Ghazi S-Lt. Fasih Bokhari–then Torpedo officer in Ghazi

She was the only submarine in the conflict arena that was deployed in the war theatre, with a mission scope of attacking only heavy and major warships of the Indian Navy. She only aided the tactical task force under the command of Commodore S.M. Anwar that launched a naval artillery battery on the Indian Air Force's radar station in Dwarka, Gujarat, India. She was also seeking , the only aircraft carrier, but did not detect her target during the entire conflict. On 9 September 1965 INS Beas made an unsuccessful depth charge attack in an attempt to make a contact with Ghazi.

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. 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. No ships were sunk or damaged in the area and Ghazi safely reported back to base.

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. K.R. Niazi was decorated with the Sitara-e-Jurat and chief petty officers were decorated with the Tamgha-i-Jurat. It is not known what Ghazis target was or what the three mysterious explosions were since no inquiry report was ever submitted.

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. In 1967 the Navy applied to renew another four-year lease deal which was duly approved by the U.S. Navy and the U.S. Government but her material state and equipment continued to deteriorate. The Navy then signed a deal with the Turkish Navy for a refit and mid-life update that was to be carried out at Gölcük in Turkey – the only facility to update the Tench-class submarines.

Because of the Six-Day War in the Middle East the Suez Canal was closed due to the Egyptian Navy's blockage in 1967, Ghazi, under the command of Commander Ahmed Tasnim, had to execute a submerged circumnavigation in 1968 from Africa to Western Europe, which began from Karachi coast to Cape of Good Hope, South Africa and then through the Atlantic Ocean. It ended at the east coast of the Sea of Marmara where the Gölcük Naval Shipyard is located. Chief of Naval Staff Admiral S.M. Ahsan had arranged necessary refitting of Ghazis computers at the Karachi Shipyard & Engineering Works (KSEW) with help of the local industry such as DESTO.

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. After passing the Cape of Good Hope, she made another stopover at Luanda, Angola for victualing and continued her journey towards Western Europe to stopover at Toulon, France, where she was greeted by the French Navy. 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. It took her two months to complete her circumnavigation of Africa and Europe.

Refitting and mid-life upgrading of her military computers reportedly cost ~$1.5 million ($11.1 million in 2015–16). The program started in March 1968 and completed in April 1970 and it is believed that the U.S-made ill-fitted World War II era Mk.14/Mk.10 naval mines were bought "secretly" from Turkey.

Eastern Front of Indo-Pakistani war of 1971

Under the command of Lieutenant-Commander Yousaf Raza, Ghazi returned to Karachi coast after successfully completing the submerged circumnavigation of Africa which was taken in order to undergo a refitting program and mid-life updates of her military computers on 2 April 1970.