The rear of HMAS AE1’s fin broken away from its footings. Photograph: Fugro Survey/AAP
It was “a tragedy for our then fledgling nation”, Payne said. “This is one of the most significant discoveries in Australia’s naval maritime history.”
The chief of navy, Vice Admiral Tim Barrett, added: “We were a young navy at the time.”
Payne and navy officials said the cause of the submarine’s loss would now be investigated. Retired rear admiral Peter Briggs, who worked on the search, told the Australian that he believed the cause was most likely “a diving accident”.
“The submarine appears to have struck the bottom with sufficient force to dislodge the fin from its footing, forcing it to hinge forward on its leading edge, impacting the casing,” he said.
The successful search, which began on Sunday, was funded by the government and the Silentworld Foundation. It was assisted by the Submarine Institute of Australia, the Australian National Maritime Museum, company Fugro Survey, the PNG government and the group Find AE1 – which is led by Briggs.
The area in which AE1 disappeared was notoriously difficult to search. In 2014, navy sources described it as “one of the most wreck-strewn areas in the region”.
Payne said the government had begun attempts to contact descendants of the crew. “I truly believe this will bring peace of mind to the family and descendants of the crew who lost their lives onboard,” she said. “Perhaps, in time, we may discover what caused the submarine to sink.”