A century-old shipwreck that holds clues to Australia's trading past has been discovered at the bottom of a treacherous burial ground for vessels off the coast of Western Australia.
The 64-metre wreck, the size of two blue whales, was spotted scattered across the sea floor among the depths of the Rottnest ship graveyard in the Indian Ocean.
The more than century-old coal hulk from Fremantle's bygone days was revealed by Hydrus, a small underwater drone that captured the wreck in 4K video and photos.
About 15 of the iron and wood ships, which were built between the 1860s-80s and deliberately sunk in the 1920-30s, have been recorded in the ship graveyard.
They were workhorses used to service steamships in WA and were built as fast clipper ships to ply the lucrative grain and wool trades between the UK and Australia.
A high-resolution replica of the wreck was able to be built using 4K geo-referenced imagery and video footage.
WA Museum curator Ross Anderson said footage from the drones was the clearest and most comprehensive data set it had received from the wreck.
"This type of high-resolution imagery is invaluable for maritime archaeological research and education on underwater cultural heritage," Dr Anderson said.
More than 1800 recorded wrecks lay off the shore of WA, holding insights into past culture, history and science.
The Rottnest ship graveyard became a burial ground for ships, naval vessels, aircraft and secretive submarines at the beginning of the 1900s.
Most of the wrecks remain undiscovered because of depths ranging from 50m to 200m, making exploration risky and costly.
A human diver or remotely operated vehicle could cost between $20,000 to $100,000 depending on the depth of the exploration.
Drones used in the latest discovery reduced the cost by 75 per cent, pinpointed the exact coordinates of the ship and fully surveyed it in less than five hours.
Teams are now trying to locate the ultra-luxury passenger ship SS Koombana which vanished into a cyclone while carrying more than 150 passengers in 1912.
