A leaked document from Interislander says its ferry Aratere ran aground after the crew pressed a wrong button, engaged the autopilot and sent the ship off course.

An Interislander safety bulletin that the Herald has seen reported the crew mistakenly pressed the “execute” button on the autopilot and did not take back control before it was too late.

The Aratere left Picton at 9.45pm on June 21 before suffering a reported steering failure and running aground shortly after. It is berthed at Waimahara Wharf in Picton and was put under a detention order.

Earlier today, Maritime NZ lifted its detention notice on the Aratere, allowing it to return to service.

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 June 21 incident. The Post said the claims stated crew did not know they needed to press the button for five seconds to turn off the autopilot.

The document said the accidental button press “commenced a chain of events which led to the grounding”.

“The accidental and early operation of the execute button on the starboard multipilot commenced a chain of events which led to the grounding. The reasons why recovery of controls that should have corrected this unplanned deviation were unsuccessful is part of the ongoing investigation and more information about this will be shared at a later date,” the document read.

Interislander executive general manager Duncan Roy said the safety bulletin was sent out to make sure crews across the ferry fleet knew about the incident.

Roy said: “It [the bulletin] is designed to quickly ensure crew awareness across the fleet after a serious incident, with what is known at the time. It does not replace the three full investigations (KiwiRail, Maritime NZ and [Transport Accident Investigation Commission] TAIC) into the grounding incident that are under way.”

Aratere’s autopilot system was not new and has been operating since 2007, he said.

“It is important that we understand all of the factors involved in the incident, including the underlying causes. A fair and thorough investigation process is crucial for all parties and is being followed.”

The Aratere ferry suffered a reported steering failure before running aground.

Maritime NZ also addressed suggestions by NZ First about what went wrong with the ferry, saying the grounding was not caused by “a crew member leaving the bridge to make a coffee”.

Meanwhile, a lawyer engaged by a maritime union has dubbed the situation “Nescafé-gate”.

Maritime NZ director Kirstie Hewlett said the regulator has inspected the ship and gathered more information over the past two weeks.

“Earlier this week, we inspected the vessel, and observed it undertake several tests while at berth involving systems, processes and equipment. Off the back of these tests we have now lifted the detention notice, but imposed conditions on the operation of the vessel.”

This means the Aratere will gradually return to service.

The Aratere when it ran aground. Photo / Tim Cuff

“Initially, the conditions will allow crew and rail freight only [four return sailings], then trucks and their drivers, followed by a limited passenger service, and then full capacity sailings to be permitted,” Maritime NZ said in a statement.

“The full return to service is subject to KiwiRail demonstrating it has implemented its return to service plan, and no further issues have been identified.”

Interislander executive general manager Duncan Roy said KiwiRail hoped to sail the vessel from Picton to Wellington tomorrow.

NZ First, a coalition Government party, posed an “extraordinary” question on X yesterday 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 NZ 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.”

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

Maritime lawyer Troy Stade, engaged by the New Zealand Merchant Service Guild union, told Newstalk ZB Drive host Heather du Plessis-Allan that the post by NZ First and Peters’ comments were “quite frankly unhelpful.

“It astounds me that the acting Prime Minister would raise an unsubstantiated rumour and conjecture in the middle of an active investigation.

“No crew went out. Nescafé-gate, if you want to call it, is little more than unsubstantiated rumour.”

The stricken Aratere in the Marlborough Sounds. Photo / Time Cuff

Labour leader Chris Hipkins said NZ First’s claim was a “serious allegation” and indicated Peters was not holding himself to his own standards.

“Winston Peters is the first to lambast anyone who makes an allegation that might in any way negatively reflect on him and demand that they front up immediately with the proof,” Hipkins told the Herald.

“New Zealand First has made a pretty big allegation here and they should front up with their evidence.”

Peters has refused to comment to several media organisations, including the Herald, about what evidence his party had to support the allegation and whether it had informed investigators.

Peters, who is currently the acting Prime Minister while Christopher Luxon is in the United States, did appear on The Country radio show earlier today and was asked by host Jamie Mackay where the rumour had started.

Peters said he saw NZ First’s social media post, which he said was not his post, and then read KiwiRail’s response to it in the Herald’s story.

“I thought ‘Crikey, that’s not a denial. That’s somebody who’s talking about an inquiry.’ Why would you need an inquiry four weeks later into something as simple as that? This is not complicated.”

Thermal drone imagery captured by Skyworks shows the moment Port Marlborough’s tugs Maungatea and Monowai free the grounded Aratere.

Peters said he was going to find out more about it.

Mackay suggested to Peters that nothing happened at NZ First without his authority. Peters said the party has a team of people.

Maritime NZ inspectors will now undertake a focused audit of the Interislander fleet in the coming weeks.

This will look at Interislander’s processes, procedures, training, and risk management and how it brings on new equipment and familiarises its personnel.

“Maritime NZ’s inspections and audits are a reflection of a point in time, and the operator, KiwiRail, has the primary responsibility for day-to-day safe operation of the vessel, and its wider fleet,” Hewlett said.

The investigation into the cause of the grounding is separate from the detention notice and audit.