• An interim report into the grounding of the Aratere ferry has been released today.
• The Interislander ferry ran aground near Picton on June 21 after suffering a steering failure.
• A leaked document in the weeks following said the incident was caused by a crew member accidentally pressing the wrong button, which engaged the autopilot and sent the ship off course.

An interim report into the grounding of Interislander’s Aratere ferry has found bridge crew did not know how to turn off the autopilot function on a new steering control system.

The report by the Transport Accident Investigation Commission (TAIC) was published this afternoon, setting out the “facts and circumstances” established to this point in its inquiry into the incident – which remains ongoing.

It said the Aratere received a new steering control system in May 2024 – a month prior to the incident - to work with the ship’s autopilot and integrated bridge navigation system.

On the June 21 sailing which departed Picton about 9.20pm, the ship’s ‘night master’ was co-piloting and supervising another master, who was re-familiarising themselves with the Aratere after commanding other vessels.

“This master, the ‘refamiliarisation master’, was controlling the engines and piloting. At the central helmsman steering console, steering, was a deck rating,” the report said.

TAIC’s chief investigator of accidents, Naveen Kozhuppakalam, said Aratere was just past its second waypoint off Mabel Island when the autopilot was engaged at 9.26pm, putting steering for the Aratere under autopilot control.

About 30 seconds later the refamiliarisation master pressed the turn execute button, intending to initiate the Mable Island waypoint turn.

“The Aratere had passed Mabel Island 36 seconds earlier, so pressing ‘execute’ told the ship’s autopilot to make the turn for The Snout headland waypoint, rightward onto a course of 73.8°, which this early in the voyage was towards land,” the report read.

The stranded Interislander ferry Aratere in Titoki Bay, near Picton. Photo / Tim Cuff

After seeing the Aratere was heading towards shore, crew attempted to press the ‘takeover’ button and turned the wheel hard to port – all to no effect.

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“The bridge team was unaware that to transfer steering control from the autopilot to the central steering console, the new steering system required them to either set the same rudder command at both consoles, or hold down takeover button for five seconds,” the report said.

With the Aratere headed towards shore at 13 knots and with a lack of steering control, crew put both engines at full astern.

Manual steering mode was established two minutes after the vessel was put on autopilot and it grounded shortly before 9.29pm.

"Aratere’s hull remained watertight, but the ship did sustain damage to the internal structure of the bulbous bow that required repair. There were no injuries. In the following 48 hours, authorities successfully refloated the Aratere using two Picton-based harbour tugs,” the report read.

The TAIC said it was continuing to collate and verify evidence directly related to the grounding and would release a final report upon completion of the full investigation.

Interislander executive general manager Duncan Roy said it was implementing “an array of improvements”, especially in change and contractor management to ensure the successful future integration of new systems on its ferries.

“The safety of our customers, the public and our people is paramount. Our response to this incident reflects our commitment to learning from it and doing better,” Roy said.

He said immediately after the grounding, Interislander worked with Norwegian company Kongsberg – which provided a new steering system – to understand what had happened.

“Having identified the cause of the event, we issued new guidance on the use of the autopilot system and upgraded re-training of deck staff on the control system. This was followed by a full competency test and updated direction on best practice use.

“We are continuing to implement recommended actions based on lessons we have learned in our own investigation. We are focused on training, change management and bridge management, and are continuing to work with Kongsberg.”

Interislander said it had established a technical advisory group (TAG) to regularly review asset performance, operational and technical standards and change management.

The TAG had worked with independent engineering consultants to review and enhance Interislander’s risk assessment processes.

Interislander said since its return to service after the incident, Aratere has made about 300 sailings. The fleet has reportedly achieved 100% reliability and 94% on-time performance for the past two months.

“On average each year, Interislander operates around 3400 crossings of Cook Strait, safely carrying more than 620,000 passengers, 230,000 cars and 73,000 commercial vehicles,” Roy said.

‘Aratere ran aground’

Emergency services responded and passengers were told to wear lifejackets. Forty-seven people were on board – eight commercial drivers and 39 crew.

There were no injuries and the boat was pulled free and refloated the next day.

It was towed back to Waimahara Wharf in Picton and was put under a detention order.

Maritime experts from Norway, Singapore and Australia travelled to New Zealand to assess the ferry following the incident. It returned to service at the end of July.

Shortly after the incident, NZ First, a coalition Government party, posted on X (formerly Twitter) about what might have caused the grounding.

“Is it true that the Aratere ran aground when someone put the autopilot on, went for a coffee, and then couldn’t turn the autopilot off in time when that someone came back ... ?”, the party posted.

Maritime New Zealand said its investigation would take several months and was focused on exploring a broad range of factors.

“However, while the cause of the grounding is yet to be formally determined, Maritime NZ’s preliminary inquiries have found that the incident was not due to a crew member leaving the bridge to make a coffee,” it said.

KiwiRail also said the “regulated number of qualified people” were on the ship’s bridge on the night of the grounding.

A leaked Interislander safety bulletin seen by the Herald reported a crew member had mistakenly pressed the “execute” button on the autopilot and did not take back control before it was too late.

The internal document, which was sent to masters and deck officers on July 5, showed the vessel’s autopilot was engaged as it passed Mabel Island, off Picton.

The crew on the bridge noticed the ship taking a wrong turn and tried to regain control. The document said this meant there was “about a minute” before crew could change the direction of the propulsion system and save the ship from running aground.

“The bridge team noticed the ship’s [sudden turn] ... and correctly tried to put the steering back into hand-steering mode but were unsuccessful in taking control. Around a minute passed before ... astern propulsion was utilised, however, it was too late and the vessel ran aground in Titoki Bay,” the document read.

“The following preliminary causation is what’s known at this point in the investigation process. While the process is under way and a more holistic picture of events is consolidated, it’s unlikely the following causes will change significantly.”

It was understood claims that none of the crew knew how to override the autopilot would make up part of investigations into the incident.

The Herald previously reported annual maintenance costs to keep the ferries running could almost double to $65 million by next year, and keeping the ferries afloat will be an “ongoing battle”.

In December last year, the Government declined KiwiRail’s request for an extra $1.47 billion for the Inter-island Resilience Connection (iReX) project after its total cost escalated to almost $3b.

As part of the project, two new rail-enabled mega ferries would have been built to replace the three current vessels.