Image showing HMAS Platypus (1917) with three of the Royal Australian Navy’s J class submarines. These submarines were based at Osborne House in Geelong between 1920-1922. The Platypus was an auxiliary ship used as a mobile base for submarines.
The Platypus was originally ordered prior to World War I to support the submarines AE1 and AE2, however, it was not completed until after both submarines had been lost. Therefore, the ship was lent to the British’s Royal Navy until the Australian Navy inherited 6 submarines from the British after the competition of World War I.