Sinking Of Royal NZ Navy Warship Due To Series Of Human Errors, Failure To Disengage Auto-Pilot: Interim Report

The sinking of the Royal New Zealand Navy (RNZN) vessel HMNZS Manawanui off the coast of Samoa in October has been attributed to human error, according to an interim Court of Inquiry report released on November 29.

The vessel ran aground on a coral reef near Upolu, Samoa, on October 6 before catching fire during survey operations. All 75 crew and passengers were safely evacuated. However, the report points out a critical lapse in the procedure as the incident’s root cause.

The inquiry found that the ship’s autopilot was not disengaged during a routine maneuver, which led to a failure in response when the crew attempted to adjust the vessel’s course.

According to the findings, the crew tried to make a starboard turn within the survey area and shift from a 340-degree heading to an easterly direction. However, the Manawanui did not respond as intended. 

The ship accelerated uncontrollably toward the reef, grounding multiple times over hundreds of meters before becoming stranded. The report revealed that full propulsion control was only restored ten minutes later when the autopilot was finally disengaged.

HMNZS Manawanui (2019) - Wikipedia
HMNZS Manawanui (2019) – Wikipedia

RNZN Chief of Navy Rear Admiral Garin Golding said, “The direct cause of the grounding has been determined as a series of human errors, which meant the ship’s autopilot was not disengaged when it should have been.”

Rear Admiral Golding explained that the crew mistakenly assessed the situation as a thruster control failure, overlooking the possibility of the autopilot being active. 

“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. This check did not occur,” he added. 

As a result, the Manawanui maintained a course toward land, culminating in the grounding and subsequent fire. Defense Minister Judith Collins described the findings as “extremely disappointing.” 

“I think you’re just as shocked as we all are, but I don’t think anyone can fault the Navy for standing up and saying this is what happened, we own it, and we’re going to fix it,” Collins added. 

The interim report marks the first phase of the Court of Inquiry, which is expected to conclude in early 2025. The next phase will examine why the autopilot error occurred and outline preventive measures. 

A separate disciplinary process would follow the conclusion of the inquiry. Golding confirmed that three personnel—the officer in charge of the ship, the supervising officer, and the commanding officer—will face a disciplinary process next year. 

Rear Admiral Golding assured the public that immediate steps have been taken to prevent similar incidents. “To provide some immediate assurance, we have conducted a series of audits in the fleet and looked to implement initial lessons identified from the interim report around training, risk management, and improving relevant orders, instructions, and procedures,” he noted. 

Loss of HMNZS Manawanui Marks A Key Setback For New Zealand Navy

The sinking of the HMNZS Manawanui represents a major blow to New Zealand, as it was the first loss of New Zealand’s naval vessel since World War II. The Manawanui was one of only nine ships in the country’s small but vital fleet. 

On the evening of October 5, 2024, the Manawanui was conducting a routine survey mission on the southern side of Apia, Samoa, in conditions of strong winds reaching up to 25 knots and moderate swells.

The survey took place in a rectangular area, and the ship worked through lanes running east to west, starting from the outer edge of the survey zone and moving inward.

At approximately 6:15 pm, the crew attempted a routine starboard turn within the survey area as part of the standard procedures. The ship’s course was initially set to 340 degrees.

However, when the crew tried to adjust the course toward an easterly direction, the ship failed to respond to the commands as expected.

The fire aboard the HMNZS Manawanui.
The fire aboard the HMNZS Manawanui. (NZDF)

The crew attempted a series of corrective actions to regain control and steer the vessel back on course, believing the ship would slow and eventually stop.

Unfortunately, these actions proved ineffective, and the vessel did not slow down; instead, it accelerated toward the coral reef. The ship grounded for the first time at around 6:17 pm, traveling at over 10 knots.  

The vessel then continued its course for about 635 meters (roughly 400 yards), grounding several times before eventually becoming stranded.

Full control of the ship’s propulsion system wasn’t restored until 6:27 pm when the autopilot was disengaged. The inability to change course or stop the ship is attributed to the autopilot remaining engaged. 

Subsequent attempts to free the ship from the reef proved unsuccessful. Emergency stations were activated following the grounding, and a damage assessment found no flooding or internal damage to the ship. However, stability evaluations indicated that Manawanui was no longer stable.

At 6:46 pm, nearly half an hour after the initial grounding, the decision was made to abandon the ship. The quick action to abandon the vessel and the decision to keep its generators running played a critical role in ensuring the crew’s safe evacuation and preventing serious harm or fatalities.