Australian researchers have used some new sonar equipment to capture stunning imagery of the shipwreck of the MV Lake Illawarra bulk carrier, which tragically sank in Hobart’s Darwent River in what is now remembered as the Tasman Bridge Disaster.
On the night of 5 January 1975, the 10,000 dwt MV Lake Illawarra struck a piling of the Tasman Bridge, causing a 127 meter span of the bridge to collapse on top of the vessel and sink it. Tragically, seven crewmembers onboard the vessel and five motorists lost their lives in the disaster, and the loss of the bridge essentially severed the link between Hobart and its eastern suburbs for years until it was fixed. The wreck of the Lake Illawarra now lies in 34 meters of water on the southern side of the new Tasman Bridge.
To map the wreck, a team of researchers from Australia’s Commonwealth Scientific and Industrial Research Oganisation used its new EM2040c, a high resolution multibeam echo sounder from Kongsberg. Not surprisingly, the imagery it returned was fascinating, and also slightly eerie.
The Kongsberg EM2040c is a shallow water sonar that is able to map the sea floor up to 500 meters and designed with mobility in mind, so that it can be lifted by a single person and fit on almost any vessel. The system generates a fan shaped acoustic beam called a swath, which can be up to four times the water depth in width. It is able to send and receive signals at a rate of 50 times per second.
Kongsberg says that the EM 2040C ensures that highly accurate data is available in real-time, making it possible to conduct very cost-effective surveys with lower requirements for post-processing, due to the high quality of data available.
The mapping of the Lake Illawarra took about an hour.
Check out the video below:
Images courtesy CSIRO