The fate of the 800-ton submarine and her 35 Australian and British crew has until now been one of the “most persistent mysteries of Australia’s military history”, according to a report on the discovery in Navy Daily, the online outlet for the Royal Australian Navy (RAN).

AE1 represented the RAN’s first loss of the war and was also the first Allied submarine casualty, coming as it did on 14 September, 1914, just over a month after hostilities broke out.

The sub went missing without issuing any signals off Rabaul on the island of New Britain in PNG. There have subsequently been 12 abortive expeditions to try to locate its remains.

The RAN set up a 13th expedition aboard search vessel Fugro Equator, funded by the Commonwealth Government and Silentworld Foundation along with the Submarine Institute of Australia, the Australian National Maritime Museum, Fugro Survey and PNG's government.

Scanning deep water off the Duke of York islands east of Rabaul in north-eastern PNG this week proved successful when a mark was located at a depth of 300m.

Closer inspection using an ROV confirmed the find to be AE1, “remarkably well-preserved and apparently in one piece”.

A small commemorative service for the officers and crew was held aboard the survey vessel, and efforts are now being made to contact descendants of the crew. The Australian and PNG government are to work together to preserve the site.

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