A MARITIME mystery, 74 years in the making, has been solved by CSIRO researchers who have discovered of the wreck of the SS Macumba, a merchant ship sunk by Japanese air attack during World War II with the loss of three Australian sailors.
In 1943 the merchant ship the SS Macumba was carrying supplies for Darwin - it never arrived.
On August 6 two Japanese aircraft opened fire at low level on the 2,500 ton steel ship and her escort HMAS Cootamundra.
Despite anti aircraft fire from both ships, the Macumba's engine room was hit. The body of one of the sailors killed was never recovered. Survivors were taken onboard the Cootamundra and the Macumba sank.
Although the location of the attack was known, no previous search was able to find the wreck until this week.
Early on Wednesday morning CSIRO researchers on the Marine National Facility research vessel Investigator solved the mystery when they located the wreck during a targeted survey in the Arafura Sea off the Arnhem Land coast.
The survey was being conducted for the Northern Territory Government while Investigator was en route from Sydney to Broome.
Investigator's advanced multibeam sonar systems were used to locate and map the wreck which was found in 40 metres of water, and appears to be upright and relatively intact.
Hugh Barker from the research ship said all on board were pleased to locate the wreck and help solve this wartime mystery.
"The search was important to everyone on board this voyage and a lot of eyes were either glued to monitors or scanning the horizon for the signs of marine life that often point to features underwater," Hugh said.
"We discovered the wreck in the middle of the night after about 10 hours of searching, which was lucky as we only had a couple more hours available for the search.
"It was also really lucky that we had an excellent team on the sonar who noticed some unusual features on the seafloor near the edge of our search area and asked for the ship to do an extra wide turn outside the search area. That's when we found it!"
Once the wreck was mapped using the ships sonar systems, a specialised drop camera was lowered into the water to photograph the site, capturing some incredible footage of the wreck and marine life around it.
"Macumba was about the same length as Investigator and it was likely that the wreck would have formed an artificial reef, providing habitat for a range of marine life," Hugh said.
"Our drop camera even got a close-up photo of an inquisitive reef shark that seemed to be guarding the site. It was a special night for all on board and we are so pleased to find the final resting place of Macumba."
Data collected by Investigator will now help inform a detailed wreck inspection report and future management as a protected historic shipwreck.
Welcoming the find, Minister for the Environment and Energy, Josh Frydenberg said "the wreckage of the Macumba will now become a part of our military history and it is correct and proper for the Government to seek its protection under Australia's Historic Shipwrecks Act."