The shelling of Port Gregory took place on 28 January 1943 during World War II. The attack was conducted by the Japanese submarine I-165 under the command of Lieutenant Commander Tatenosuke Tosu as part of the attempts to divert Allied attention away from the evacuation of Guadalcanal in the Solomon Islands. None of the ten shells fired at Port Gregory caused any damage, and the attack was not noticed by the Allied naval authorities until a radio signal sent by Tosu was intercepted and decoded a week later.
Purpose
During the Pacific War Japanese submarines occasionally operated off Western Australia. In early 1943 the major Japanese headquarters across the Pacific were directed to use their forces to make small attacks on Allied positions in an attempt to divert attention away from the planned evacuation of Guadalcanal, Operation Ke. In mid-January, the commander of the Japanese Southwest Area Fleet ordered that I-165 be dispatched to attack Allied shipping off north-western Australia. As part of the fleet's contribution to the diversionary operations, I-165 was also directed to bombard a coastal Australian town. It is likely that the busy port town of Geraldton was selected for bombardment. The submarine I-166 was ordered to conduct a similar mission against the Cocos Islands. I-165 sailed from Surabaya in the occupied Dutch East Indies on 21 January 1943.
The attack
On the evening of 27 JanuaryI-165 arrived just north of Geraldton. While preparing for the attack, the crew of I-165 observed three aircraft and what Tosu believed was a destroyer in the area. Tosu decided to postpone his bombardment mission, and sailed north. While sailing on the surface the submarine passed within of what was identified as a destroyer without being noticed. The following evening I-165 surfaced off the village of Port Gregory just after midnight. From a range of, she fired about ten 100-mm shells from her Type 88deck gun at a derelict crayfish cannery, which the submarine's crew had mistakenly identified as an ammunition factory. None of the shells caused any damage. Tosu did not attempt to observe the results of his submarine's bombardment, and resumed patrolling off the coast of Western Australia. Two Australian coastwatchers stationed near Port Gregory noticed gunfire at night on 28 January, but neither observed any shells landing. Allied naval authorities only learned of the attack when the submarine's battle report radio signal was intercepted and decoded a week later. I-165 returned to Surabaya on 16 February without having sunk any Allied ships during her patrol. Australian naval historianDavid Stevens has noted that "clearly as a diversion operation the bombardment had been an abject failure. Nevertheless, for the Allied navies it provided another graphic example of the poor planning and inadequate doctrine so common in the Japanese submarine force". The attack on Port Gregory was one of three submarine shellings on Australian towns and cities, the other two being the attacks on Newcastle and Sydney in June 1942.
