When Australia considered options for its navy in the years after Federation, the range, firepower, and affordability of cruisers made them an attractive option. A cruiser could counter the kind of surface-based threats to trade and communications that Australia expected in the event of war. Accordingly, the Royal Australian Navy’s fleet prior to the outbreak of the First World War included three light cruisers, HMA Ships Encounter (I), Melbourne (I), and Sydney (I).
HMAS Encounter dressing ship during the Fleet Entry in October 1913.
After the war, the signatories of the 1922 Washington Naval Treaty sought to prevent the kind of naval arms race that had preceded the First World War. Signed by the victorious allies, the treaty limited the number and total displacement of new battlecruisers and battleships, but not the number of cruisers. Instead, heavy cruisers were limited to a maximum displacement of 10,000 tons, and guns of 8-inch diameter.
As a result, on the outbreak of the Second World War, the RAN fleet included the light cruiser HMAS Adelaide (I), a Great War-era ship, and the modern light cruisers HMA Ships Hobart (I), Perth (I), and Sydney (II). In addition to these, the RAN had two heavy cruisers, the flagship HMAS Australia (II), and HMAS Canberra (I). These were known as “treaty cruisers”, because their displacement and armaments matched the limit set by the Washington Treaty. After the Imperial Japanese Navy sank Canberra at the battle of Savo Island in August 1942, the Royal Navy transferred a replacement heavy cruiser to Australia, which commissioned as HMAS Shropshire in April 1943.
Technological change after the Second World War meant that the cruiser was no longer an economical choice for Australia. Tasks that had once been the role of the cruiser could now be conducted by missile-capable destroyers, or frigates optimised for anti-submarine warfare.