HMAS Onslow (SS 60/SSG 60) is one of six s, previously operated by the Royal Australian Navy (RAN). The submarine was named after the town of Onslow, Western Australia, and Sir Alexander Onslow, with the boat's motto and badge derived from Onslow's family heritage. Ordered in 1963, Onslow was laid down at the end of 1967 by Scotts Shipbuilding & Engineering Company in Scotland, launched almost a year later, and commissioned into the RAN at the end of 1969.
During her career, Onslow became the first conventionally powered submarine to be fitted with anti-ship missiles, and was successful in wargames, "sinking" a seven-ship flotilla during Exercise Kangaroo 3 in 1980 and the United States supercarrier at RIMPAC 1998.
After being decommissioned in March 1999, Onslow was then presented to the Australian National Maritime Museum in April, where she is preserved as a museum ship.
Design and construction Onslow is one of four Oberon-class submarines ordered in 1963. The last of this group, Onslow was laid down by Scotts Shipbuilding & Engineering Co. in Greenock, Scotland on 4 December 1967. She was launched by Princess Alexandra, The Honourable Lady Ogilvy on 3 December 1968, and commissioned into the RAN on 22 December 1969.White, Australian submarines, p. 199 The boat was named after the coastal town of Onslow, Western Australia, which was in turn named after Sir Alexander Onslow, the third Chief Justice of Western Australia. Onslows motto, Festina Lente (Latin for "Hasten Slowly"), is shared with the Onslow family, and the ship's badge contains a judge's wig.White, Australian submarines, p. 200 Although this was the only use of the name by the RAN, two surface ships of the Royal Navy have previously been named .
The submarine is long, with a beam of , and a draught of when surfaced. At full load displacement, Onslow displaces 2,030 tons when surfaced, and 2,410 tons when submerged. The two propeller shafts are each driven by an English Electric motor providing 3,500 brake horsepower and 4,500 shaft horsepower; the electricity for these is generated by two Admiralty Standard Range supercharged V16 diesel generators. These can propel the submarine at up to on the surface, and up to when submerged. Onslow has a maximum range of at , and a test depth of below sea level. When launched, the boat had a company of 8 officers and 56 sailors, but by the time she was decommissioned, the number of sailors had increased to 60. In addition, up to 16 trainees could be carried.
Unlike other submarines in her class, Onslow is fitted with a four-man diver access hatch, allowing for easier deployment and recovery of special forces divers.Shaw, HMAS Onslow, p. 10
Armament The main armament of Onslow are six bow torpedo tubes, capable of firing torpedoes or releasing sea mines. The British Mark 8 torpedo was initially carried by the submarine; this was replaced by the wire-guided Mark 23.Shaw, HMAS Onslow, p. 21 During a refit from 1982 to 1984, Oberon became the first conventionally-powered submarine in the world to be fitted with anti-ship missiles—specifically, the UGM-84 Sub Harpoon. At the same time, the Mark 23 torpedoes were replaced by the United States Mark 48 wire-guided torpedo. As of 1996, the standard payload of Onslow was a mix of 20 Mark 48 Mod 4 torpedoes and Sub Harpoon missiles. Some or all of the torpedo payload could be replaced by Mark 5 Stonefish sea mines, which were deployed through the torpedo tubes.
The submarine's secondary armament consisted of two stern-mounted, short-length torpedo tubes: these were intended for use against pursuing submarines, but the development of steerable wire-guided torpedoes shortly after the boat entered service made these redundant, and they were closed off during the 1982–84 refit.Shaw, HMAS Onslow, p. 19 The aft tubes fired Mark 20 anti-submarine torpedoes.
Operational history
1970–1981 Onslow arrived in Sydney at the conclusion of her delivery voyage to Australia on 4 July 1970. On board was Vice Admiral Sir Victor Smith, at the time the Chief of Naval Staff, who had embarked at Brisbane. The boat visited Pearl Harbor later that year; arriving without being detected by the USN until she surfaced in the middle of the harbour.Pratley, Farewell to a quiet achiever, p. 59 Onslow returned to Pearl Harbor in 1971 to participate in the RIMPAC multinational naval exercise.Shaw, HMAS Onslow, p. 6 During the exercise, a practice torpedo fired by the United States Coast Guard Cutter failed to disengage as designed and hit the submarine—the damage was a small dent near the stern and a crack in the port propeller shaft seal causing flooding in the after ends. Submarine went to emergency stations, all water tight hatches sealed and Salvage blow was started to the flooding compartment which had four crew inside (Tony,Ned, Gra, and Mal) Onslow was not permitted to dive again until damage was inspected via dry-dock back in Australia after a six week wait in Pearl Harbour for a local docking that failed to eventuate.
Onslow became the first vessel of the RAN to be assigned to the ANZUK force in Singapore on 22 July 1972.Gillett, Warships of Australia, p. 198 During another ANZUK deployment, in 1974, the boat's attack periscope was damaged when it came in contact with the log probe of the frigate . The boat returned to Australia on 18 December. On 5 May 1975, Onslow began a two-year refit at Cockatoo Island Dockyard, becoming the first Australian submarine to use the dockyard's new slave dock.Jeremy, Cockatoo Island, p. 64 This dock had been built specifically for refit work on Oberon-class submarines, and was the main location of all Onslows refits until 1990. In 1977, Onslow was presented with the Gloucester Cup, marking her as the most efficient warship in the RAN during the previous year—Onslow was the first submarine to receive the award.
In 1980, Onslow participated in Exercise Kangaroo 3 as an opposing submarine.Richards & Smith, Onslow's Jolly Roger, pp. 11–12 During the exercise, Onslow carried out successful simulated attacks on all seven surface ships involved in the exercise without being 'sunk' herself, including a simultaneous 'attack' on two United States Navy (USN) amphibious warfare vessels and a RAN replenishment ship while they were under escort by the other four warships. To indicate her success, the submarine flew a Jolly Roger from her communications mast upon her return to port, which was marked with the silhouettes of her seven targets: the s and , the , the , the , the , and the .
On 1 March 1981, Onslow participated in wargames with a Royal New Zealand Navy frigate off the coast of Sydney.Seconds from Disaster [Sunday Night segment] While operating at periscope depth, the submarine spotted an 'enemy' P-3C Orion aircraft and stopped snorting (the process of taking in air to operate the boat's two diesel generators and expelling the produced exhaust through a snorkel) in preparation to go deep. Both generators were turned off, but upon diving, it was quickly discovered that the starboard diesel had failed to switch off or had restarted and as the exhaust snorkel was sealed, the carbon monoxide exhaust filled the submarine. Onslow rapidly resurfaced, and the exhaust was pumped from the submarine. Able Seaman Christopher Passlow, who had been on the lower deck of the submarine at the time, died of asphyxiation and carbon monoxide poisoning, while another eighteen were rendered unconscious or were convulsing because of blood poisoning.White, Australian submarines, p. 203 Upon returning to base, doctors found that one-third of the 66 survivors had absorbed twice the lethal limit of carbon monoxide into their blood. The crew onboard were taken to Soldiers Beach surf club and provided with free alcohol for 3 days before returning back to duties. They were not compensated in any other way as stated they were by the RAN.
The RAN Board of Inquiry into the incident concluded that the accident was caused by human error—the duty engineer failed to shut down both engines—but members of Onslows complement disagree with this, claiming the problem to be mechanical in origin. Changes were made to Submarine Service operating procedures as a result of the Inquiry, but the investigation and subsequent report remained classified until 2009, when the information was acquired by the Sunday Night newsmagazine program under the Freedom of Information Act. When interviewed by Sunday Night in March 2009, the deputy Chief of Navy, Rear Admiral Davyd Thomas (who had been Passlow's divisional officer prior to the incident) promised counselling for the survivors, and claimed that prior treatment of the Onslow submariners was due to a limited understanding of post-traumatic stress disorder back in the 1980s.
1982–1990 Onslow underwent a modernisation refit from 1982 until 1984, becoming the third Australian Oberon to be modernised.White, Australian submarines, p. 202 As part of the modernisation, integrated data processing and fire control systems were installed, and the boat was fitted with Micropuffs passive ranging sonar.White, Australian submarines, p. 201 The torpedo payload was upgraded to the United States Mark 48 wire-guided torpedo. In addition to new torpedoes, the modernisation allowed Oberon-class submarines to carry and fire the Harpoon anti-ship missile through the torpedo tubes: Onslow became the first conventionally-powered submarine in the world to be fitted with guided anti-ship missiles.Lind, The Royal Australian Navy – Historic Naval Events Year by Year, p. 303
Onslow was the first Australian submarine to visit the west coast of the United States of America when she arrived in San Diego on 17 July 1985.Lind, The Royal Australian Navy – Historic Naval Events Year by Year, p. 304 The boat made goodwill visits to the cities of San Francisco and Seattle during mid-August, before participating in the Royal Fleet Review for the 75th anniversary of the Royal Canadian Navy.Australian Submarine to visit San Francisco, PR Newswire, p. 7
Onslows "safe to dive" certificate ran out just after Christmas 1989.Grigson, Nothing doing down under for our subs, p. 3 The Australian government had been trialling a program whereby refit work was tendered out to the private sector; delays in selecting the winning company and allocating the funds meant that an 18-month refit of the submarine scheduled to begin at the start of 1990 did not commence on time. Australian Defence Industries (ADI) was awarded the $100 million refit contract for Onslow and sister submarine in July.Grigson, $100M submarine refits to stay in Sydney, p. 2 Cockatoo Island's slave dock was transferred to the ADI facilities at Garden Island in November 1990, and was used for the refit. It was later found, during arbitration between the Australian Government and Cockatoo Island Dockyard for various issues, that by tendering out the submarine refits to other companies, the government was in breach of contract with the Dockyard; A$17.3 million in compensation was awarded to the dockyard in August 1996 for loss of profits and overhead costs.Jeremy, Cockatoo Island, pp. 52–3
1990–1999 In the early 1990s, four of Onslows sister boats were decommissioned from service. By 1996, Onslow and Otama were the only members of the class in active service.