(USS Diablo in 1964, after the Fleet Snorkel Conversion and just before the submarine transferred to Pakistan. This photo gives a good view of the plexiglass bridge windshield which was later recovered off the wreck.)
USS Diablo underwent the conversion in 1963. As modified,
USS Diablo displaced 1,570t surfaced and 2,414t submerged. The refitted submarine could make 20kts surfaced, 12kts snorkeling with the diesels, or 8 ¾kts submerged on battery power. The underwater endurance on battery power remained limited; 97NM at 2kts or 48 hours maximum.
USS Diablo now had a crew of 76 (9 officers and 68 enlisted men). The submarine carried the SS-2 radar with an average range of 21NM, the AN/BLR-6 ESM system, and AN/BQR-2 sonar with a range of 4 NM.
The armament of
USS Diablo in postwar American (and later, Pakistani) service remained the WWII-era Mk14 torpedo. The Mk14 was the main US Navy submarine torpedo of WWII. It had a range of 2 ¼NM at 46kts or 4 ½NM at 30kts, and had a 507 lbs TNT warhead. This was an unguided, straight-running torpedo inferior to the post-WWII homing designs. None the less, because of the huge quantity built, it remained in frontline US Navy use through the Korean War and in second-line service into the 1970s. The Mk14 was always the torpedo type included with exported American WWII-veteran submarines.
(The WWII-era Mk14 which was heavily exported after the war and used in the US Navy until the early 1970s.)
Transfer to Pakistan
In 1963,
USS Diablo was loaned to Pakistan on a four-year basis under terms of the Security Assistance Program (SAP) with an option to renew or purchase afterwards. On 1 June 1964, the Pakistani ensign was raised and
USS Diablo became
PNS Ghazi.
USS Diablo was selected as the freshly-done Fleet Snorkel upgrade would give the Pakistani navy a quality asset, but would not take one of the more valuable GUPPY-upgraded WWII submarines out of American use.
PNS Ghazi arrived at her new home port of Karachi, Pakistan in September 1964.
PNS Ghazi was Pakistan’s first-ever submarine.
(PNS Ghazi arrives at Karachi, Pakistan in September 1964.)
THE 1965 WAR
The 1965 Indo-Pakistani War was the culmination of several border disputes. The war started on 5 August 1965.
PNS Ghazi was assigned to patrol south of West Pakistan, and ordered to seek out only “major” Indian warships, understood to be carriers, cruisers, and possibly large destroyers. India tried throughout the war to de-escalate the conflict and limit it as much as possible to a regional ground war. As such,
PNS Ghazi‘s prime target; the aircraft carrier
INS Vikrant; was not to be found.
(INS Vikrant had been launched as HMS Hercules by Great Britain during WWII but left unfinished when WWII ended. The incomplete carrier was later bought by India and finished to Indian specifications.)
The Indian navy was on the lookout of
PNS Ghazi and the submarine had to be wary of detection. On 9 September, the Indian frigate
INS Beas made an unsuccessful depth charge attack. Later an Indian Alize ASW plane flew directly over
PNS Ghazi while the submarine had the snorkel mast and periscope exposed. It was a miracle that the plane didn’t detect the submarine.
(The cramped control room of PNS Ghazi.)
On 17 September 1965,
PNS Ghazi acquired a surface contact which was identified as the frigate
INS Brahmaputra, one of the Indian navy’s more modern warships at the time.
PNS Ghazi fired three WWII-era Mk14 torpedoes at the contact and increased depth to evade counter-attack. According to the submarine’s logs, three distinct explosions were heard at the time the torpedoes should have impacted, and
PNS Ghazi was credited with sinking
INS Brahmaputra.
(A photo taken inside PNS Ghazi’s engine room during the 1965 war. The Fleet Snorkel-converted submarines retained their WWII propulsion system, four Fairbanks-Morse diesel engines and two Elliot electric motors.)
In fact,
INS Brahmaputra was not sunk, and had not even been hit. The frigate never acquired either a submarine nor incoming torpedoes, and had not dropped any depth charges. No ships were damaged or sunk in the area. It’s unknown to this day what
PNS Ghazi‘s target was or what the three explosions were.
The war ended on 23 September 1965 and
PNS Ghazi was recalled to Karachi.
Refit in Turkey
The USA placed a weapons embargo on Pakistan in 1965.
PNS Ghazi badly needed a refit at that time. To circumvent the embargo, Pakistan negotiated a shipyard deal with Turkey. Turkish shipyards were well familiar with WWII-vintage American submarines as the Turkish navy was operating several. Moreover, in 1953 Gölcük Shipyard in Turkey had been provided the Fleet Snorkel blueprints and had actually done two Fleet Snorkel conversions, on
TCG Gür and
TCG Inonu (formerly
USS Chub and
USS Brill during WWII) which had transferred unmodified in 1948. The refit cost $1.5 million ($11.1 million in 2015 dollars) which was a fairly good bargain.
(PNS Ghazi in Karachi harbor in 1970, following the Turkish refit.)
Because the Suez Canal was still closed from the Arab-Israeli Six Day War,
PNS Ghazi had to go the long way around South Africa and up through the Atlantic. The refit started in March 1968 and was completed in April 1970. It’s believed that the WWII American mines
PNS Ghazi used in 1971 were bought “under the table” from Turkey at this time.
