HMAS Australia served as the Royal Australian Navy's (RAN) only capital ship and appeared for service just before the start of World War 1 (1914-1918). She was the second of three warships built by British naval industry to make up the "Indefatigable-class". This class of warship included lead-ship HMS Indefatigable followed by HMAS Australia and HMS New Zealand. HMS New Zealand was intended for the nation of New Zealand itself but ended up in service with the British Royal Navy (RN) for her part. The group was built during the period spanning 1909 to 1913 and entered commissioned service in 1911. One was lost while the last was retired in 1923; two of the lot were scrapped.
HMAS Australia was categorized as a "battlecruiser", a capital-level warship with reduced armor protection and firepower when compared to full-fledged battleships of the period. This made them less expensive to procure and operate in the long term while also allowing for increased ocean-going speeds, a useful trait in hunting down adversaries in open water.
HMAS Australia was ordered on December 9th, 1909 and her keel laid down at Yard No. 402 by the John Brown & Company of Clydebank on June 26th, 1909. Launched on October 25th, 1911, she entered commissioned service on June 21st, 1913 - just in time for World War 1. She fought under the motto of "Endeavor" for her time at sea and was awarded battle honors for her wartime service at Rabaul and in the North Sea.
As built, the warship had a rated displacement of 18,800 tons under standard load and up to 22,500 tons under full load. Overall length reached 590 feet with a beam measuring 80 feet and a draught down to 30.3 feet. Installed power included 31 x Babcock & Wilcox boiler units feeding 4 x Steam turbines developing 44,000 horsepower to drive 2 x Shafts under stern. All told, this provided the vessel with a top ocean-going speed of 25 knots and a range out to 6,700 nautical miles (7,700 miles).
Aboard was an operating crew complement of 818.
Armament consisted of 8 x 12" BL Mk.X main guns held in four twin-gunned turrets making up the primary battery. While the forward and rear gun placements were traditional, a unique facet of the primary battery arrangement was in the placement of the central two gun turrets, these being seated at midships at each side of the vessel (detailed as "wing turrets"). A full broadside, therefore, could bring six total 12" guns to bear at any one time. During travel, the portside gun was stowed facing forward while the starboard side gun faced aft.
Beyond this were 16 x 4" BL Mk.VII secondary guns in single-gunned mountings. 2 x 18" torpedo tubes were also carried.
Armor protection reached up to 6" at the belt, 2.5" at the deck, 7" at the turret barbettes, and 7" at each primary turret.
Her profile included a raised bow with a single turret seated at the forecastle. Aft of this emplacement was the bridge superstructure which contained the forward mast works. Three smoke funnels were seated inline near midships though the superstructure was broken up in two places. The second mast was positioned towards the stern while the upper hull line stepped down.
HMAS Australia's wartime career was rather subdued: she only ever fired her guns in anger twice with little in the way of material results. Her ocean-going service involved a mix of exercises and patrols for even during the famous clash of the two major fleets of the war - the British "Grant Fleet" and the German "High Seas Fleet" - in the Battle of Jutland (May-June 1916), HMAS Australia found herself under repair due to an earlier collision with HMS New Zealand. As such she was destined to not see any of the action related to the largest naval battle of the conflict. Beyond this, a late-career mutiny due to poor morale marred an otherwise solid career.
After the war, with her services no longer needed, the ship was relegated to training before being decommissioned on December 12th, 1921, the vessel being placed in reserve, and given up for good on April 12th, 1924 (scuttled near Sydney's Head).