HMNZS Manawanui sank on Samoan reef due to human error, report finds – ‘disciplinary investigation’ under way

• The HMNZS Manawanui sank off Samoa on October 6 after striking a reef and catching fire.
• Human error has been identified as a cause of the vessel’s loss, including the failure to disengage autopilot in the sinking of the $100 million Navy ship in the Pacific.
• The Chief of Navy confirms a “disciplinary investigation” is now under way.

Human error and the failure to disengage an autopilot control has been confirmed as the root cause of a New Zealand Navy ship running aground and sinking in the Pacific, a report has concluded.

New Zealand’s Navy and Defence Minister fronted a media conference today to deliver the final findings of a Court of Inquiry into how one of the country’s warships sank off the coast of Samoa last year.

The report stated: “The court was satisfied that the direct cause of the grounding of the ship was a series of human errors by Witnesses 2 and 4.″

Chief of Navy Rear Admiral Garin Golding said there was a “disciplinary investigation” under way, but would not comment further.

Commander Yvonne Gray was the captain of the HMNZS Manawanui when it left New Zealand on the ill-fated trip to the Pacific where the ship sank.

Addressing the nation, Defence Minister Judith Collins, KC, and Golding unveiled the Court of Inquiry’s final report into the ship’s loss.

They were at a briefing alongside the president of the Court of Inquiry, Commodore Melissa Ross.

The $100 million HMNZS Manawanui motored into a reef off the coast of Samoa at a speed of 11 knots last October, travelling 365 metres after the initial impact and grounding multiple times along the way.

It took 10 minutes for the crew to regain full control of the ship’s propulsion system, when crew members disengaged the autopilot, the final report found.

The ship sank as a result of hull damage but crew members were able to evacuate.

Defence Minister Judith Collins, Commodore Melissa Ross and Rear Admiral Garin Golding fronted the release of the final report into the Manawanui's sinking. Photo / Jason Dorday

“The direct cause of the grounding has been determined as a series of human errors in that the ship was put on a heading towards land and the autopilot mode was not disengaged,” the report stated.

“Remaining in autopilot resulted in the ship maintaining a course of 340 degrees toward land, until grounding and eventually stranding.”

Collins said the ship’s sinking was an “incredibly serious incident” but that in part thanks to numerous acts of bravery during the evacuation, New Zealand was fortunate it ended as a terrible rather than tragic event.

She said the Court of Inquiry was an important next step in New Zealand’s response to the incident and it was crucial to learn from it.

“I am confident we will,” Collins said.

Collins said this “shouldn’t have happened”.

”Really bad things happen from time to time and hopefully it never happens to any other navy as well.”

Ross said a sound understanding was developed of the direct causes of the grounding and loss of HMNZS Manawanui, along with other contributing factors, as a result of the inquiry.

She described the grounding as “a series of human errors”. She said the ship was put on a course for land and it was left on autopilot.

“It was a difficult and stressful experience for some,” Ross said of those who provided evidence to the court.

After the grounding, she said, attempts were made to manoeuvre the ship off the reef and the crew searched the ship to determine the extent of the damage.

“No damage could be seen from inside the ship, however, due to the ship’s violent movement, the crew’s assessment of suspected damage to tanks and void spaces that lined the ship’s hull and the fact the ship had lost propulsion due to damage, the commanding officer made the decision to abandon ship,” Ross said.

That decision was the right one, she said, and it saved the lives of all aboard.

Ross said there were many accounts of leadership, professionalism and teamwork during the abandonment phase and on the water before rescue.

She said the ship suffered a series of catastrophic fires before capsizing and sinking.

“The fire was likely caused by electrical circuits being damaged in the grounding, which then ignited a fuel source.

Naval boss: Report’s release a sign that he was ‘owning’ the $100m loss after human error

”The loss of the ship was a result of hull damage sustained over the period the ship was in contact with the reef that resulted in down-flooding, leading to the ship capsizing and eventually sinking,” Ross said.

Navy Chief Rear Admiral Garin Golding said he was making results of the Court of Inquiry public as part of “owning it”.

Chief of Navy, Rear Admiral Garin Golding speaking at the release of the final report into the sinking of the HMNZS Manawanui. Photo / Jason Dorday

Asked how New Zealanders should view the Navy after losing a $100m ship after not turning off the autopilot, Golding said it was “a bad day for the Navy”.

“With the assistance of external sources, we have completed reviews of areas such as risk management, oversight and documentation,” Golding said.

“Our team has also conducted assurance analysis and reports for a number of the ships before they depart on operations.”

Golding said there were a range of issues, including the lack of commonality across the fleet. “Which means our people need to constantly adapt to new procedures each time they change ships.”

“We need to do things differently. We need to adapt to new technologies, change the way we approach what we do and find new ways to continue to deliver upon what is expected of us.

”This means investing in new technologies, streamlining the ways of working, reviewing and adapting training and making sure our people are set up to succeed in their roles.”

Golding said these were “generational changes”, which would ultimately set up the Navy for decades into the future.

“We have a lot of work to do, but with change comes opportunity.”

Asked what the Samoan Government’s reaction to the report was, Golding said it had only just received it today.

On environmental damage, he said independent testing of the environment around Manawanui showed no evidence of contamination.

Aside from the costly human error, also noted in the report was the bravery of a local villager who paddled to the reef where they found a life raft and evacuated a casualty to shore.

An interim version of the report delivered in November last year had earlier found human error resulted in HMNZS Manawanui’s sinking.

It comes as Navy teams continue salvage efforts at the wreck. Last week they cut into secure compartments to retrieve weapons and ammunition.

HMNZS Manawanui, a specialist survey and dive support vessel, first ran into trouble on Saturday, October 5, 2024, when it struck a reef in Samoan waters.

It began to list and Commander Yvonne Gray gave the order to abandon ship.

A fire broke out in the engine room and the $100m vessel sank that Sunday morning, off the south coast of the Samoan island of Upolu.

HMNZS Manawanui foundered off the coast of Upolu, Samoa, on October 5.

Interim report blamed ‘human error’ for sinking

Human error was the root cause of the vessel’s sinking, the interim report concluded.

Golding said the direct cause of the grounding was because of a series of human errors, resulting in the ship’s autopilot “not being disengaged when it should have been”.

Chief of Navy Rear Admiral Garin Golding and Defence Minister Judith Collins also addressed the media about the inquiry last year. Photo / Alex Burton

He earlier said the crew did not realise Manawanui remained on autopilot and mistakenly believed its failure to respond to direction changes was the result of a thruster control failure.

“Having mistakenly assessed a thruster control failure, standard procedures should have prompted the ship’s crew to check that the ship was under manual control rather than in autopilot,” Golding said late last year when the interim report was released.

“This check did not occur. Remaining in autopilot resulted in the ship maintaining a course toward land, until grounding and eventually stranding.”

Golding previously said the incident had “obviously” had an impact on New Zealand’s reputation, and the Navy needed to “own” its mistake.

He said the investigation panel was looking at three people for responsibility for the incident: the pilot, the officer overseeing the pilot, and the officer overseeing the ship.

Timeline of HMNZS Manawanui’s sinking:

• On Saturday, October 5, 2024, HMNZS Manawanui was conducting survey operations on the southern side of Apia, Samoa, in a strong breeze of up to 25 knots and moderate swell.
• The survey was conducted in a box-shaped area, running east to west in survey lanes that start on the outside, working inwards.
• About 6.15pm, the ship’s crew attempted a routine turn to starboard, initially to a course of 340 degrees, within the survey area, as part of a turn. The crew tried to turn off the 340-degree course to starboard towards an easterly course but the ship did not respond as intended.
• Shortly after, Manawanui left the approved survey area and, in an effort to stop the ship, the crew conducted further actions they believed should have resulted in the ship essentially braking.
• Manawanui did not slow or stop. Instead, it started to accelerate towards the reef, grounding for the first time at or about 6.17pm at a speed of more than 10 knots.
• The ship then travelled around 635 metres before becoming stranded, grounding multiple times along the way.
• Full control of Manawanui’s propulsion system was not regained until 10 minutes later, at 6.27pm, when the ship’s autopilot was disengaged. The inability to turn the ship to an easterly direction from the 340-degree course and stop it is attributed to it being in autopilot mode.
• Unsuccessful attempts were then made to manoeuvre the ship off the reef.
• Manawanui was brought to emergency stations after the grounding, and searches were conducted to check for damage.
• No damage or flooding was detected inside the ship. However, stability assessments made after the grounding indicated Manawanui was no longer stable.
• About 6.46pm, roughly 30 minutes after the initial grounding, the decision was made to abandon ship.
• The timeliness of the decision to abandon ship and to keep Manawanui’s generators running contributed to the successful abandonment process and likely prevented serious injuries or death.
• The ship suffered a series of catastrophic fires after being abandoned, before capsizing and sinking on the morning of Sunday, October 6.

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