KEY POINTS:
The New Zealander presumed drowned after falling overboard near the Barrier Reef is understood to be a 46-year-old Aucklander, Mark Ross.
Ross was one of eight New Zealanders among a crew of 13 on board the Geo Sounder, a seismic survey ship making its way to Singapore when the accident happened in the early hours of last Saturday.
The ship's owner, Subsea, and the Australian Transport Safety Bureau have launched investigations into the incident, as they search for answers about how the crew member could have been lost overboard.
Subsea commercial manager Jeff Hogg told the Herald on Sunday it appeared Ross had been with another crew member on the deck around 3am when he went overboard.
Two life preservers were thrown out to him, and the rescue boat launched, but crew were unable to find him. A day-long air search, with help from a cargo boat that was in the area, was called off that night.
"That was a decision made in conjunction with the Australian Maritime Safety Association, the captain and the company," Hogg said. "It was based on what they knew at the time. They decided there was no point in continuing, there was no more that could be done."
The ship was 100km north of Willis Island in international waters at the time of the accident. It was sent back to Cairns on Monday, where investigators spent two days interviewing crew members, including one who fractured an ankle during the launch of the rescue craft.
Asked whether the men had been drinking and about the conditions at the time, Hogg said: "We're asking similar questions, but that's something we want to get to the bottom of. At the moment I haven't got an answer."
All the crew had been offered trauma counselling. "They are all pretty shaken up, but they were all determined to continue the voyage. It's definitely not something any of us what to go through again."
The lifebuoys had been recovered, he said.
ATSB team leader of maritime investigations, Michael Squires, said crews worked 24-hour rotating shifts, and it was not unusual for them to be "out and about" in the early hours of the morning. Sea conditions were "reasonably good".
The crew was employed by Taranaki company Wendell Offshore, which supplies rigs, crews and catering to the oil and gas industry.
The ship is Norwegian registered and operated by Fugro Survey Private of Singapore. It had been doing exploratory work in the Kermadecs for the London listed company Neptune Minerals, which this year signed Subsea to undertake sampling operations on Brothers, a hydro thermal undersea crater 400km northeast of White Island and rich in "black smoker" vents containing lucrative minerals.
Crews on ships like the Geo Sounder worked five- to six-week swings, an industry source said. They could have up to 30 crew - a seismic crew, often specialists from around the world, and a marine crew. "It's a lifestyle. Generally there's a lot more work in Australia, and they'll often do winter here [in NZ] then go to Southeast Asia or even India, if there's work."
He said it was rare for someone to be lost overboard, but it did happen. Survival depended on the water temperature: "It's not a nice way to go. You wouldn't survive after about 10 minutes in New Zealand, it would be a bit longer in Australia."
He said it was unlikely the crew on the Geo Sounder had been drinking, as alcohol was generally not allowed on offshore boats.
Results of the investigations are not expected to be released for several months. The Geo Sounder left Cairns for Singapore on Thursday.
