Diving up to 100m into the Indian Ocean west of Perth, a team of elite technical divers are uncovering and identifying shipwrecks in conjunction with the Western Australian Museum. Some of these shipwrecks have been at the bottom of the sea for more than 100 years.

Archaeologists from the Museum’s Maritime Heritage department have been working with a team of deep-ocean divers from WreckSploration, an organisation that develops 3D models from images taken at wreck sites, to identify unknown shipwrecks in Rottnest’s Ships Graveyard.

The identification of unknown shipwreck sites in the Graveyard allows a further understanding of their significance in the context of Western Australian maritime history.

Recently, our archaeologists accompanied the divers on a charter to the Graveyard. The objective of this trip was for the divers to dive down to a depth of 88m to an unknown shipwreck known as Site 04. Deep dives such as these require the expertise of these elite divers who can take only four minutes to descend, and up to two hours to ascend to avoid decompression sickness.  

Once on Site 04, using underwater scooters and kitted out with multiple cameras and lights, the divers worked quickly around their decompression limits to take more than 1000 images of the wreck. These images were later developed into a 3D model using photogrammetry technology.

The WA Museum has historical records of the vessels that have been scuttled in the Graveyard over time. However, many of the sites on the seafloor remain unknown.

The identification of unknown vessels in the Graveyard is based on their construction characteristics, such as mast and deck configuration, as well as the overall length of the site. By using these historical records our maritime archaeology team was able to compare them with the 3D model of Site 04, and identified it as Knowsley, built in 1864 and scuttled in 1923.

Knowsley is one of the oldest wrecks in Rottnest’s Graveyard and is one of eight models created by WreckSploration. The model and information on the Knowsley can be viewed here

If a photograph is available in historical records, it can also prove invaluable in identifying a wreck. As an example, the below image is a comparison between a historic photograph of Sesa as a hulk and an image of the wreck on the Graveyard seafloor. It shows the matching length and layout of original lower masts and additional pole masts fitted for the coal hulk trade.

NB: Don't miss the public lecture by the WA Museum and WreckSploration on Rottnest's Ships Graveyard. Sunday 16 June 2024, 2pm - 3pm, WA Maritime Museum, Victoria Quay. Admission fees apply. Book now.

Black and white image sourced from the Sunday Times (Perth, WA 1902-1954), Sunday 8 July 1928, pg1.
The wreck image source is WreckSploration.

Video courtesy of 7NEWS Perth.