In late May to early June 1942, an attack was made on Sydney Harbour. This attack was made by the Japanese. On May 31st late at night Japan sent 3 midget submarines into Sydney Harbour in attempt to sink the Allies war ships. In these midget submarines there would only be to people.
The Allies defence was not up to scratch, prior to the attack the Harbours defence mechanisms consisted of 8 anti-submarine indicator loops and an anti-submarine boom net. Anti-submarine indicator loop was a cable beneath the water that laid on the floor of the ocean that was used to pick up the passing onto our territory of an enemy submarine. The Allies had 6 of which were outside the Harbour and having 1 between North Head and South Head and having the other between South Head and Middle Head. The Allies boom net was between George’s Head on Middle Head and Green Point on the inner South Head. These anti-submarine boom nets used an anti-torpedo and a submarine defence net which was spanned the width of the Harbour from the points and heads that were named above. Shortages on the needed materials prevented the Allies from completing the boom net before the attack. Very inconveniently on the day of the attack, all of the 6 outer indicator loops were not active and 2 were not functioning properly due to inexperienced workers on the stations.
Japans plan was to launch the 3 midgets one after another on the night of May 31st – June 1st, 1942 . The first midget submarine was supposed to pass through the head at 6:30pm but there was heavy seas and swell so they were delayed by over 1 hour. But once set off the other 2 midgets were sent of within a 20 minute interval. The targets were left up to the commanders of the submarines but they were highly recommended to go for the Allies aircraft carriers battleships.
The first midget submarine to enter the harbour was the M-14 and it was detected by the south head loops at 8:01pm but the Allies didn’t take much notice of it because for the last 3 years before the attack the loops had been giving faulty signals and on this night there was heavy civilian traffic, so they let it slide. 14 minutes after the submarines launch it was spotted by a watchman from the Maritime Services Board, the midget submarine then hit the Pile Light, so reversed and backed into a net of the Allies. 2 light cruiser, Lolita and Yarroma, we sent out to investigate and determine what the object stuck in the net was. Once they confirmed that what was caught in the net was a midget submarine, they then had to wait of permission to fire, though once permission was granted the cruisers were to low to fire and in the meantime the 2 crew man inside of the M-14 committed suicide by allowing the submarine to sink, destroying the forward section. The second submarine to enter the Harbour was the M-24. It had followed a ferry into a net but then started heading towards the Sydney Harbour Bridge. HMAS Whyalla and Geelong fired at the midget submarine but didi little damage, around the same time that the M-14 was fired at by Chicago, 2 other midget submarines entered the Harbour. The M-21 and the I-22.
At 12:25am the next morning the M-24 fired its first torpedo, destroying the Dutch submarine, Kuttabul. It broke and sank the ship while killing 19 Royal Australian Navy and 2 Royal Navy Sailors. A blast was the sent of that damaged M-21, which then rose to the surface before sinking, the crew of the M-21 also committed suicide.
In a result, the Allies lost much more than Japan though the winner of this attack is still undecided.