British insistence that the Royal Navy could not alone bear the burden of the Empire's Naval Defence led to the commissioning of the submarines OXLEY and OTWAY in 1927. However, because of the London Naval Treaty of 1930 and the onset of the Great Depression, these boats were handed back to the Royal Navy. For the third time the RAN Submarine Service was nullified. It is noteworthy that OXLEY was sunk in error by the British submarine HMS TRITON in late 1939. Only the Commanding Officer and one sailor survived the disaster and she became the first submarine casualty of WWII. Apart from the Dutch submarine 'K9' used for training during the war years, Australia did not operate submarines for 36 years. However, during the period 1949-69 a total of 10 Royal Navy 'A' and 'T' class submarines were stationed in Sydney. The cost of operating these submarines was met jointly by the governments of Australia and New Zealand.

The fourth and more permanent attempt to establish the Royal Australian Navy's Submarine Service began with the purchase in 1967 of the six 'Oberon' class boats from the United Kingdom. In August of that year the Submarine Support Depot HMAS PLATYPUS was commissioned for the support of the new submarines. The Oberon class boats, HMA Submarines OXLEY, OTWAY, OVENS, ONSLOW, ORION and OTAMA have served the RAN and our nation faithfully over the ensuing three decades.

The Oberon class have now ended their operational life. The submarines OXLEY, OTWAY, OVENS, ORION, OTAMA and ONSLOW have all been withdrawn from service.

But we generally did quite well on all fronts...