page_title: Axis naval activity in Australian waters
section_title: East coast submarine patrols (January–June 1943)
hierarchical_section_title: Axis naval activity in Australian waters / 1943 / East coast submarine patrols (January–June 1943)
caption_attribution_description: AWM caption: "SYDNEY, NSW. 1943. STARBOARD BOW VIEW OF THE HOSPITAL SHIP CENTAUR. NOTE THE PROMINENT RED CROSSES AND GREEN LINES ON HER HULL. RED CROSSES ARE ALSO ATTACHED TO HER FUNNEL. THE CENTAUR WAS TORPEDOED AND SUNK WITH HEAVY LOSS OF LIFE BY A JAPANESE SUBMARINE ON 1943-05-14."
context_page_description: Although Australia was remote from the main battlefronts, there was considerable Axis naval activity in Australian waters during the Second World War. A total of 54 German and Japanese warships and submarines entered Australian waters between 1940 and 1945 and attacked ships, ports and other targets. Among the best-known attacks are the sinking of HMAS Sydney by a German raider in November 1941, the bombing of Darwin by Japanese naval aircraft in February 1942, and the Japanese midget submarine attack on Sydney Harbour in May 1942. In addition, many Allied merchant ships were damaged or sunk off the Australian coast by submarines and mines. Japanese submarines also shelled several Australian ports and submarine-based aircraft flew over several Australian capital cities.
  The Axis threat to Australia developed gradually and until 1942 was limited to sporadic attacks by German armed merchantmen. The level of Axis naval activity peaked in the first half of 1942 when Japanese submarines conducted anti-shipping patrols off Australia's coast, and Japanese naval aviation attacked several towns in northern Australia.
context_section_description: Japanese submarine operations against Australia in 1943 began when I-10 and I-21 sailed from Rabaul on 7 January to reconnoitre Allied forces around Nouméa and Sydney respectively. I-21 arrived off the coast of New South Wales just over a week later. I-21 operated off the east coast until late February and sank six ships during this period, making it the most successful submarine patrol conducted in Australian waters during the Second World War. In addition to these sinkings, I-21's floatplane conducted a successful reconnaissance of Sydney Harbour on 19 February 1943.
  In March, I-6 and I-26 entered Australian waters. While I-6 laid nine German-supplied acoustic mines in the approaches to Brisbane this minefield was discovered by HMAS Swan and neutralised before any ships were sunk. Although I-6 returned to Rabaul after laying her mines, the Japanese submarine force in Australian waters was expanded in April when the four submarines of Submarine Squadron 3 (I-11, I-177, I-178 and I-180) arrived off the east coast and joined I-26. This force had the goal of attacking reinforcement and supply convoys travelling between Australia and New Guinea.
  As the Japanese force was too small to cut off all traffic between Australia and New Guinea, the Squadron commander widely dispersed his submarines between the Torres Strait and Wilson's Promontory with the goal of tying down as many Allied ships and aircraft as possible. This offensive continued until June and the five Japanese submarines sank nine ships and damaged several others. In contrast to 1942, five of the ships sunk off the Australian east coast were travelling in escorted convoys at the time they were attacked. The convoy escorts were not successful in detecting any submarines before they launched their attacks or counter-attacking these submarines. The last attack by a Japanese submarine off the east coast of Australia was made by I-174 on 16 June 1943 when she sank the merchant ship Portmar and damaged U.S. Landing Ship Tank LST-469 as they were travelling in Convoy GP55 off the New South Wales north coast. Some historians believe that RAAF aircraft searching for I-174 may have sunk I-178 during the early hours of 18 June, but the cause of this submarine's loss during a patrol off eastern Australia has not been confirmed.
  The single greatest loss of life resulting from a submarine attack in Australian waters occurred in the early hours of 14 May 1943 when I-177 torpedoed and sank the Australian hospital ship Centaur off Point Lookout, Queensland. After being hit by a single torpedo, Centaur sank in less than three minutes with the loss of 268 lives. While hospital ships—such as Centaur—were legally protected against attack under the terms of the Geneva Conventions, it is unclear whether Commander Hajime Nakagawa of I-177 was aware that Centaur was a hospital ship. While she was clearly marked with a red cross and was fully illuminated, the light conditions at the time may have resulted in Nakagawa not being aware of  Centaur's status, making her sinking a tragic accident. However, as Nakagawa had a poor record as a submarine captain and was later convicted of machine gunning the survivors of a British merchant ship in the Indian Ocean, it is probable that the sinking of Centaur was due to either Nakagawa's incompetence or indifference to the laws of warfare. The attack on Centaur sparked widespread public outrage in Australia.
  The Japanese submarine offensive against Australia was broken off in July 1943 when the submarines were redeployed to counter Allied offensives elsewhere in the Pacific. The last two Japanese submarines to be dispatched against the Australian east coast, I-177 and I-180, were redirected to the central Solomon Islands shortly before they would have arrived off Australia in July. The Australian Naval authorities were concerned about a resumption of attacks, however, and maintained the coastal convoy system until late 1943 when it was clear that the threat had passed. Coastal convoys in waters south of Newcastle ceased on 7 December and convoys off t
caption: AHS Centaur.
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