Bruce Robertson was a wireless operator during the Second World War when he heard something through his headset that didn’t make sense.
“I was on a watch at two o’clock in the morning, and was turning a dial around on a receiver, listening in case an aeroplane came back in trouble, and this loud Morse code hit me in the ears,” Robertson said. “I couldn’t write it down. It didn’t make our letters. And so I thought, ‘It’s got to be Japanese.’ There was no other [explanation], so everyone came running, and sure enough it was Japanese.”
It was the night of 31 May 1942 and three Japanese midget submarines had entered Sydney Harbour. Robertson was on the midnight to dawn watch at Richmond and had heard “what they called Kana code” in the early hours of 1 June 1942.
“We didn’t have any radar, [but] we had two direction finding stations … and they honed in on the signal to find where it was coming from. We concluded it was a sub, and it was. It was right off Sydney Heads, and it was the mother sub for the midget submarines that had come into the harbour, and we think that perhaps it was waiting there to pick them up when they came out of the harbour, but, of course, they never came out of the harbour – they were destroyed.”
One of the midget submarines became entangled in the boom net across the harbour and was blown up by its occupants. A second entered the harbour and fired torpedoes at the cruiser USS Chicago. It missed the target, but one torpedo struck the barracks ship HMAS Kuttabul, killing 21 men. The submarine then disappeared, its fate a mystery until it was discovered by a group of amateur divers off Sydney's northern beaches in November 2006. A third midget submarine was destroyed by depth-charges before it could fire. The midget submarine on display in Anzac Hall at the Australian War Memorial is a composite of two of the submarines that entered the harbour that night, a night Robertson will never forget.
“There was a Lockheed Hudson bombed up on standby all the time to patrol on the coast – there were 37 ships sunk and destroyed by torpedoes just on our coast here – but this bomber couldn’t find them,” Robertson said. “It was a dark night, and they were probably submerged anyway … but that’s how things started, and the signal came through the air force in my headphones … The air force didn’t even realise this had happened until a couple of years ago, and they became very excited about it.”