By Michael Brooks

Counter-mine warfare technology developed by the Defence Science and Technology Organisation (DSTO) for the Navy has been used to end a 50-year-old mystery about the fate of a missing Japanese midget submarine.

State-of-the-art sand column imaging technology developed to detect and identify mines buried in the sea floor was used to conduct a magnetometer survey of a site thought to be the resting place of one of three Type A midget submarines that attacked Sydney Harbour in WWII.

The technology was jointly developed by DSTO and Midspar Systems and used by the NSW Heritage Office to investigate claims that the midget submarine that vanished in 1942 had been found in the Hawkesbury, some 50kms north of Sydney.

Dr Brian Ferguson, Principal Research Scientist, Maritime Operations Division, DSTO, told Navy News that the hi-tech sonar technology used to investigate the site is being developed for the Navy under Project Sea 1436.

Dr Ferguson said the sub bottom profiler sonar technology can identify and capture images of objects from 15 to 50 metres below the sea floor, depending on the softness of the sediment.

“This technology is being developed under Sea 1436 to allow the Navy to detect and identify mines that are buried in the sea floor,” he said.
He said this sonar tomography system enabled the authorities to identify what was under several tonnes of sand without disturbing what was potentially a war grave.

Dr Ferguson said the advanced sonar technology was mated with a development vehicle, the “Littoral Surveyor,” and is the only state-of-the-art system of its kind in Australia.

Tim Smith, a Maritime Archaeologist at the NSW Heritage Office, said the Littoral Surveyor was used recently to confirm searches using side-scan sonar and a remote-sensing archaeological surveys.
However, Mr Smith said other emerging maritime technologies including a 3D animation program developed by DSTO would soon put the spotlight on other important Navy wrecks.

Mr Smith said the NSW Heritage Office would employ new technologies to help preserve RAN history by employing remotely operated vehicles (ROVs) to film the Navy submarine AE2 that sank in the Dardenelles in 1915, and the battleship HMAS Australia that was scuttled off Sydney Heads in 1924.

Mr Smith said DSTO volunteers had developed a 3D animation program that would allow an ROV to film inside the RAN submarine AE2, which achieved fame for its operations in the Dardanelles.

Roger Neill, G-UPS, Maritime Platform Divison, DSTO, said the 3-D animation program based on original building plans dating back to 1913 would guide an ROV through the conning tower so it could film inside AE2.

Dr Neill said that DSTO had also agreed in principle to provide an ROV to assist the project, but certain issues about costs still had to be resolved before the “green-light” would be given.

Mr Smith said the interior of AE2 is expected to be quite revealing because she was abandoned in great haste by the crew after being hit by naval gunfire.

“AE2 has basically been on the sea floor, totally undisturbed for the past 90-years since being sunk in 1915,” he said.

Meanwhile, an ROV or a two-man submersible will film the Indefatigable-class battlecruiser HMAS Australia later this year.
Australia was scuttled in 1924 off the coast of Sydney under terms of the Washington Treaty but had recently been discovered in about 400 metres of water by a company conducting a survey for offshore capable routes.

“Filming Australia will help us preserve the Navy’s heritage and also allow us to see the damage she sustained from the RAN warships that sank her with gunfire,” Mr Smith said.

Mr Smith said plans are also underway to locate entire squadrons of WWII-era combat aircraft that were dumped off the coast of NSW soon after the end of the war. He said an ROV would be used to determine the condition of these aircraft.