HMAS Platypus was a submarine depot ship and base ship operated by the Royal Australian Navy (RAN) between 1919 and 1946. Ordered prior to World War I to support the Australian submarines and , Platypus was not completed until after both submarines had been lost, and she was commissioned into the Royal Navy from 1917 to 1919.
After the RAN acquired six J-class submarines, Platypus was recommissioned as an Australian warship. She was repurposed as a destroyer tender after the J class was removed from service in the 1920s, tasked with supporting the two O-class submarines during 1929 and 1930. After the submarines were placed in reserve, Platypus was renamed HMAS Penguin and operated as a depot ship until 1941. The ship assumed her old name and was relocated to Darwin, then Cairns for use as a base ship. After a refit in 1944, Platypus operated as a repair vessel in New Guinea waters until she was placed into reserve in 1946. Platypus was sold for scrap in 1958.
Construction and acquisition
Platypus was ordered as a submarine tender by the Australian government before the outbreak of the war to service the new E-class submarines, and . She was built by John Brown and Company at Clydebank in Scotland, and launched on 28 October 1916. By the time she was completed, both submarines had been lost, and she was instead commissioned into the Royal Navy on 21 March 1917.
Operational history
Royal Navy
At the conclusion of the war, the ship was transferred to the Royal Australian Navy and was commissioned into the RAN on 25 March 1919.
Royal Australian Navy
Platypuss main role was to support the RAN's six J-class submarines, which she sailed with from Britain to Sydney between April and July 1919.
Platypus and all six J-class submarines were based at Geelong in February 1920. Due to the poor condition of the submarines and financial pressure on the RAN the Royal Australian Navy Submarine Service was disbanded in May 1922 and Platypus was redesignated as a destroyer tender. Platypus reverted to her original role as a submarine tender in 1929 when the RAN acquired two O-class submarines but was used as a depot ship after these submarines were placed into reserve in 1930. She was renamed HMAS Penguin on 15 August 1930.
In October 1932, a mutiny occurred aboard Penguin. The mutiny was in protest of the decreases in sailor pay and conditions: Depression-era cutbacks had impacted them harder than officers, as they had no avenues of protest.
Decommissioning and fate
Platypus was placed into reserve on 13 May 1946, paid off on 1 November 1956 and was sold for scrap on 20 February 1958.