Switched Off Navigation Sounders a Factor in Nuyina Grounding Says ATSB
A decision to switch off the navigational echo sounders to avoid interfering with scientific instruments is emerging as a key factor in the brief grounding of Australia’s research vessel Nuyina in October last year. This is according to the Australian Transport Safety Bureau (ATSB), which has released its preliminary report detailing events leading to the grounding of the $528 million vessel off Heard Island, some 4,000 kilometers southwest of Perth on October 13.
On that day, the state-of-the-art research vessel was conducting drone survey operations over the shore of Heard Island, close to an area of uncharted seafloor with 37 marine crew and 85 expeditioners on board. The vessel had arrived at Heard Island from Casey station, Antarctica, with the purpose of the visit being to support field science operations on the island as part of the Australian Antarctic Program’s (AAP) first voyage of the 2025–2026 Antarctic season.
Notably, the Heard Island campaign was the AAP’s first dedicated environmental management visit to Heard Island in more than 20 years. It included planned landings by scientists, using helicopters and small craft to check on the state of the island’s unique flora and fauna, as well as small-scale remotely operated vehicles operations and mapping the bathymetry around the island.
During that first day, the vessel conducted scientific operations using remotely piloted aircraft (RPA) before moving away from the coast and conducting bathymetric mapping operations overnight. The survey operations were conducted using scientific acoustic instruments, including a high-resolution multi?beam echo sounder (MBES) mounted on one of the ship’s drop keels.
After completing overnight survey operations, the vessel arrived at a holding position five miles north of Dovers Moraine in the early hours of the following day. By about 0800, the weather had improved, and Nuyina was moved closer inshore to a position in water depths of about 30 meters. The position was close enough to shore to allow for effective RPA operations while remaining clear of the area marked as “unsurveyed” on the chart.
At this location, the drop keel was retracted from its lowest working position to its highest working position, which left it protruding 750 mm below the keel. The MBES was left switched on and continued to provide depth information as the ship proceeded with the survey operations. At about 1430, the voyage leader requested the master to move the ship from its location off Fur Seal beach to a location north of Cape Bidlingmaier, with the master understanding that a track close to shore would be beneficial for continued RPA flights.
The master and second officer went on to discuss the route to the new location in more detail, after which he constructed the route at the ECDIS planning station. At this point, the MBES was still collecting data, having been used for overnight bathymetric surveys in deeper water. 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. This meant the depth information was not displayed on the ECDIS, and could not be used to generate navigational alarms,” explained Angus Mitchell, ATSB Chief Commissioner.
While the master tried to correct the issue with the ECDIS, the second officer followed an electronic bearing line that had been loaded earlier to guide the ship along the coast while it was conducting the drone flights. A short time later, the acoustics operator contacted the bridge by phone to advise that the multibeam was showing a depth of 15 meters. Shortly after, the master ordered “stop engines,” followed a short time later by “dead slow astern.”
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At about the same time, the acoustics operator contacted the bridge again to warn of shallow water. However, Nuyina then briefly grounded, with its retractable drop keel initially impacting the seabed, followed by the ship’s hull. The grounding caused substantial damage to scientific instruments, with the ship’s hull sustaining scratches and paint damage. The ship continued with its operations at Heard Island as well as a scheduled resupply operation at Davis Station in Antarctica before returning to Hobart.
ATSB has termed the grounding a serious incident and intends to issue a final report of the investigation later in the year.
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