Navigation sounders turned off before Nuyina hit ocean floor, ATSB report notes
The report found Nuyina's navigational echo sounders were switched off so as to avoid acoustic interference. (Supplied: AAD)
In short:
A preliminary report has revealed new details about how an Australian research vessel became grounded off Heard Island last year.
RSV Nuyina hit the seabed after the ship's navigational echo sounders were turned off to avoid acoustic interference during a survey.
What's next?
A final report will be released at the conclusion of the investigation.
The Australian Transport Safety Bureau (ATSB) has outlined how the Australian research vessel, RSV Nuyina, became grounded off Heard Island on October 13 last year.
The preliminary report stated the grounding occurred while the Australian Antarctic Division's $528 million icebreaker was conducting drone surveys over the shore of Heard Island, close to an area of uncharted sea floor.
Heard Island is 4,000km south-west of Perth.
The Nuyina icebreaker entered service in 2021. (Supplied: AAD/Pete Harmsen)
Navigation sounders switched off to stop interference
ATSB chief commissioner Angus Mitchell said the ship was using instruments on a retractable drop keel, which was 75 centimetres below the vessel's nominal 9 metre draft.
The report said to avoid acoustic interference, the ship's navigational echo sounders were switched off.
"Depth information from the multi-beam system was shown on a dedicated display on the bridge but was not fed into the ship's integrated bridge system," Mr Mitchell said.
"This meant the depth information was not displayed on the electronic chart display and information system, and could not be used to generate navigational alarms."
The team then planned a route to the new location. However, at this point they saw it was not visible on their display.
They tried to correct, but couldn't successfully before hitting shallow water.
"Nuyina then briefly grounded, with its retractable drop keel initially impacting the seabed, followed by the ship's hull,"the report said.
"The vessel then cleared the shallow water and drifted away from the coast, before the crew stopped its movement and held position.
"The drop keel was retracted for inspection, revealing substantial damage with mounted instruments damaged or missing," the report noted.
"The hull of the ship itself only sustained scratches and paint damage."
There were 37 marine crew and 85 expeditioners on board at the time.
Following the incident, the report said Nuyina continued its operations at Heard Island as well as a scheduled resupply operation at Davis Station in Antarctica before returning to Hobart.
The hull of the ship sustained scratches and paint damage, the ATSB found. (Supplied: AAD)
Mr Mitchell said the ATSB's investigation had so far included interviews with key personnel, examination of recorded data and CCTV footage, and the gathering of operational documentation and historic and recorded bathymetric data.
Preliminary reports contain no analysis or findings, which will be detailed in the investigation's final report.
Nuyina has faced multiple challenges since it first arrived in Hobart, including:
- Mechanical problems that kept it out of action for the 2022-23 season
- A costly refuelling debacle linked to it being banned from travelling under Hobart's Tasman Bridge
- Faulty cranes that meant only half its cargo could be offloaded at Mawson Station
- A lack of marine-based science voyages in its first three years
Nuyina's 30-year operating budget has also blown out, compared to initial estimates.