By Cristy Burne
Two Japanese planes attacked the SS Macumba, a 2,500-tonne cargo ship in waters off Arnhem Land, on the northern tip of the Northern Territory, on August 6, 1943.
The boat sank, and for 74 years its final resting place remained a mystery.
But then, in the dead of night on October 4, 2017, the mystery was solved.
A research boat from Australia’s science agency, the CSIRO, was passing near where Macumba was hit. The crew of the Investigator was given 12 hours to find it.
The team used sonar pulses to search the sea floor, and by studying how the pulses bounced back to the top could work out what might be on the ocean’s bottom.
After 10 hours they spotted some “unusual” features. The ship turned for another look.
“It was very early in the morning, about 1am, so everyone was very tired,” says Hugh Barker, who was in charge of the boat. “As soon as [the wreck] appeared on our screens, everyone was celebrating.”
The team used sonar to map the wreck, which was 40 metres down. They also dropped a camera to photograph it. They discovered the wreck was teeming with life, including “an inquisitive reef shark that seemed to be guarding the site”, says Mr Barker.
The wreck will now be protected as a historic shipwreck.
Sonar, short for sound navigation and ranging, uses sound waves or pulses to “see” in the water. The sound bounces off objects on the sea floor back to the ship and helps to draw a picture of the ocean floor.
Source US National Ocean Service
Frozen in time
Shipwrecks are like time capsules, says Ross Anderson, from the Western Australian Museum.
“Everything on a shipwreck is frozen in an exact moment of time,” he says. “Shipwrecks, like all archaeological sites and heritage places, are tangible links to our past.”