Interim factual report on grounding of Interislander ferry Aratere

31 Oct 2024
the Aratere with tugs readying to refloat the ferry
the Aratere with tugs readying to refloat the ferry. TAIC photo

The Transport Accident Investigation Commission (TAIC) has published its interim factual report on the grounding of KiwiRail’s Interislander ferry Aratere during its Picton to Wellington sailing on the evening of 21 June 2024.

The report sets out the facts and circumstances established to this point in the Commission’s inquiry, which is ongoing. It draws evidence from the ship’s voyage data recorder, the steering control system and interviews with crew.

In May 2024, Aratere received a new steering control system to work with the ship’s autopilot and integrated bridge navigation system. In the next three weeks, Aratere completed 83 Cook Strait crossings.

For the Aratere’s 9:20pm sailing, the ship’s Night Master was co-piloting and supervising another Master, who was re-familiarizing themselves with the Aratere after commanding other vessels. This Master, the ‘Refamiliarization Master’, was controlling the engines and piloting. At the central helmsman steering console, steering, was a Deck Rating. 

TAIC’s Chief Investigator of Accidents, Naveen Kozhuppakalam, says Aratere was just past its second waypoint off Mabel Island when the autopilot was engaged at 2126:01, putting steering for the Aratere under autopilot control. 

“At 2126:30, the re-familiarisation master pressed the turn execute button, intending to initiate the Mabel 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.”

“Around 31 seconds after the ‘execute’ command, the night master saw Aratere was heading towards shore and called the helmsman back to the central steering console. In turns, the Helmsman, the officer of the watch and the night master pressed the ‘takeover’ button and turned the wheel hard to port, all to no effect. Aratere continued its turn toward the coast. 

“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.”

At 2127:43, with Aratere heading towards shore at 13 knots and helmsman lacking steering control, the night master put both engines at full astern. It took 21 seconds for the port propeller and 38 seconds for the starboard propeller to begin turning astern.

Finally, at 2128:06 manual steering mode was established; the port rudder moved hard to port, the starboard rudder moved to port, and the night master commanded the officer of the Watch to start a bow thruster to assist manoeuvring. By 2128:34, Aratere had slowed to about 7 knots at the 10-metre sounding, then slower, and by 2128:50 it had grounded. 

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 Commission is continuing to collate and verify evidence directly related to the grounding. across multiple lines of inquiry. Upon completion of the full investigation, the Commission will issue a final report that report will include analysis of the facts, identification of safety issues, and – if necessary -- recommendations.