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HMAS Onslow

Australian National Maritime Museum - Joy of Museums - HMAS Onslow

HMAS Onslow was one of six Oberon-class submarines operated by the Royal Australian Navy (RAN). The submarine was named after the town of Onslow, Western Australia, and Sir Alexander Onslow, the third Chief Justice of the Supreme Court of Western Australia.

Although never involved in war, there have been a number of critical operational incidents which occurred during Onslow’s service. One dangerous incident forced a change in  RAN procedures. It occurred in 1972, when HMAS Onslow was performing dive tests off the continental shelf outside Sydney Heads. One of crew who had been transferred to the RAN Submarine Service against his will, refused to obey an order to close the valve on a ballast tank, causing it to overfill with seawater and forcing the submarine into a steep crash dive.

The crash dive took Onslow to a depth of 366 metres (1,201 ft), well beyond the 200-metre (660 ft) safe operating depth of the Oberon class, before another sailor was able to close the valve. Seven tons of water had been taken on by the ballast tank, and there was not enough compressed air available to completely empty the ballast tank and to allow the submarine to rise.

HMAS ONSLOW

Australian Navy submarine HMAS ONSLOW (SS-60)

Fortunately Onslow’s twin propeller screws eventually go the submarine to the surface even with a partially full ballast tank. The sailor responsible for the incident was beaten by his comrades and removed from the submarine in a straitjacket upon the boat’s return to submarine base HMAS Platypus. This incident led the RAN to change submarine service to volunteers only.

Onslow was decommissioned in 1999, and was presented to the Australian National Maritime Museum, where she is preserved as a museum ship.

Essential Facts:

  • Exhibit:                     HMAS Onslow (SS 60/SSG 60)
  • Namesake:               Town of Onslow, Western Australia
  • Builder:                    Scotts Shipbuilding and Engineering, Greenock, Scotland
  • Commissioned:       1969
  • Decommissioned:  1999
  • Motto:                       Festina Lente; Latin “Hasten Slowly”
  • Status:                       Museum ship
  • Class and type:        Oberon-class submarine
  • Displacement:         2,030 tons surfaced; 2,410 tons submerged
  • Length:                     295.2 ft (90.0 m)
  • Beam:                        26.5 ft (8.1 m)
  • Draught:                   18 ft (5.5 m)
  • Propulsion:
    • 2 × Admiralty Standard Range supercharged V16 diesel generators
    • 2 × English Electric motors
    • 3,500 bhp, 4,500 shp
    • 2 shafts
  • Speed:
    • 12 knots (22 km/h; 14 mph) surfaced
    • 17 knots (31 km/h; 20 mph) submerged
    • 11 knots (20 km/h; 13 mph) at snorkel depth
  • Range:                    9,000 nautical miles (17,000 km; 10,000 mi)
  • Test depth:            200 metres (660 ft)
  • Complement:        8 officers, 56 – 60 sailors
  • Museum:               Australian National Maritime Museum

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“Set your course by the stars, not by the lights of every passing ship.” Omar N. Bradley

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Photo Credit:By GordonMakryllos (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons 2) By PH1 (NAC) JAMES G. MCCARTER (http://www.defenseimagery.mil; exact source) [Public domain], via Wikimedia Commons