Navigational sounders off during icebreaker’s grounding
Australia’s Antarctic icebreaker RSV Nuyina ran aground while its navigational echo sounders were turned off to prevent interference with scientific instruments, a report has revealed.
A preliminary report from the Australian Transport and Safety Bureau detailed the circumstances of the October incident on remote Heard Island in the Southern Ocean.
The $529 million ship had scratches and paint damage to its hull, and scientific instruments were damaged or lost due to the “extensively damaged” falling keel.
The grounding, briefly described in the report, occurred while the crew was conducting drone surveys near an unexplored area of the seafloor.
An underwater device with a high-resolution multi-beam echo sounder system was collecting data.
The report stated that the ship’s navigational echo sounders were turned off to prevent acoustic interference with the multi-beam system.
This meant that depth information was not displayed on the ship’s electronic chart display and information system and could not be used to generate navigational alerts.
Nuyina was being repositioned when its operators noticed their new route was not on the forward navigation screen.
The ship followed a preloaded bearing before its acoustic operator called the bridge to tell it that the multi-beam system indicated a water depth of 15 meters, followed by “shallow water.”
Despite the ship’s captain ordering the engines to be stopped, Nuyina’s keel, a movable fin, struck the seabed and then her hull.
The ship was ultimately able to continue operations on Heard Island and resupply an outpost in Antarctica before returning to Hobart.
Nuyina’s user manual states that the echo sounder must be operational at all times.
However, according to the security bureau report, the science manual states that the navigation echo sounders should be turned off when the science echo sounders are taking measurements.
The report does not include analysis or findings that will be published as a final report at the end of the review.
Several safety changes were made after the incident, including the development of the Heard and McDonald Islands navigation decision support guide.
