It was towed to Waimahara wharf in Picton and was placed under arrest warrant.

Maritime experts from Norway, Singapore and Australia traveled to New Zealand to assess the ferry after the incident. He returned to service at the end of July.

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

“Is it true that the Aratere ran aground when someone turned on the autopilot, went to get a coffee, and then couldn’t turn off the autopilot in time when that person returned.. .?,” the party posted.

Maritime New Zealand said its investigation would take several months and would focus on exploring a wide range of factors.

“However, although the cause of the grounding has not yet been formally determined, preliminary investigations by Maritime NZ have revealed that the incident was not due to a member of the crew leaving the walkway to make a coffee,” he added.

KiwiRail also stated that the “regulated number of qualified persons” were on the ship’s bridge the night of the grounding.

Leaked Interislander safety bulletin seen by the Herald reported that a crew member mistakenly pressed the “run” button on the autopilot and did not regain control until it was too late.

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

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

“The bridge team noticed the (sudden turn) of the vessel…and correctly attempted to return the helm to manual steering mode, but were unable to gain control. About a minute passed before stern propulsion was used, but it was too late and the ship ran aground in Titoki Bay,” the document states.

“The following preliminary causality is what is known at this stage of the investigative process. Even though the process is ongoing and a broader picture of events is consolidated, the following causes are unlikely to change significantly.”

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

THE Herald previously reported annual maintenance costs to keep ferries running could nearly double to $65 million by next yearand keeping ferries afloat will be a “continuing battle”.

In December last year, the government refused KiwiRail’s request for an extra $1.47 billion for the Inter-island Resilience Connection (iReX) project after its total cost soared to nearly $3 billion.

Under the project, two new mega rail ferries would have been built to replace the current three vessels.