Theory of Sydney's loss backed by pictures

A piece of the puzzle surrounding Australia's greatest naval tragedy, the 1941 loss of HMAS Sydney II, has clicked into place after researchers found evidence to support a long-held theory about how it was sunk.

What appeared to be merely a shadow in photographs taken when the wreck was found in 2008 has been revealed by new images as a 15cm shell hole through the Sydney's bridge at the compass platform.

The pictures, released yesterday, appear to confirm the theory that Australia's best-known warship was likely disabled by German raider HSK Kormoran within about 30 seconds of battle, hampering her ability to fight back.

The photographs were taken by Curtin University researchers aboard the vessel Skandi Protector as part of a $2.4 million expedition in conjunction with the WA Museum.

WA Museum chief executive Alec Coles said the photos were a "remarkable early discovery" and supported the theory Sydney's bridge was destroyed and command structure lost quickly.

"Some people would say it's no surprise because that's what (German captain Theodor) Detmers wrote in his account of the engagement," he said.

"What we haven't had until now is any conclusive evidence. When there was the expedition to the wreck in 2008 the images were pretty inconclusive and shadowed. These images are as clear as anything."

Skandi Protector was heading towards the Kormoran wreck late yesterday.

The Sydney sailed from Fremantle on November 11, 1941 to escort a troopship.

While returning on November 19 she encountered the Kormoran, disguised as a Dutch merchant ship, and was attacked.

Both ships were destroyed and the Sydney sank with all 645 crew. For many years her fate was a mystery until the Sydney and Kormoran wrecks were found about 200km west of Shark Bay.

Curtin University director of strategic projects Paul Nicholls said the university was collaborating with the museum to provide technology to capture the "unique heritage value of these ships so they can be investigated, managed and interpreted for future generations".