Incident Overview and TAIC’s Inquiry Process
In the weeks leading up to the incident, Aratere underwent significant updates, including the installation of a new Kongsberg steering control system. This system was part of KiwiRail’s initiative to replace older, less supported systems, aimed at ensuring smoother coordination with the vessel’s autopilot and bridge navigation. After the upgrade in May, the ferry completed 83 Cook Strait crossings without reported issues, demonstrating its operational readiness and the effectiveness of the new steering mechanisms under standard conditions.
However, during the critical evening voyage, several factors involving the bridge team’s unfamiliarity with certain system functions, combined with potential procedural missteps, led to a breakdown in command control. The interim report details these events, providing initial insights into potential safety issues and the areas the Commission will examine further as it prepares its final findings.
The Night of the Grounding: A Breakdown of Events
On 21 June, the Aratere set off for Wellington at approximately 9:20 pm. The bridge team for the night included a Night Master overseeing operations, a Refamiliarisation Master who was adjusting to the Aratere after time away, an officer of the watch, and a deck rating acting as the helmsman. The team coordinated navigational duties, with the Refamiliarisation Master managing engine and helm controls for most of the journey.
system data) Photo Credit: TIAC
As the Aratere passed its second waypoint near Mabel Island, the Night Master engaged the autopilot, transferring navigational control from the helmsman to the automated system. This standard transition was complicated, however, and when the Refamiliarisation Master pressed the “execute” button—intended to activate a planned turn—at 9:26 pm, 36 seconds after the ship passed Mabel Island, nothing happened. Consequently, the autopilot interpreted the command as an instruction to begin a sharp right turn toward the Snout headland, aiming the vessel toward land rather than along its intended course.
Despite the bridge team’s efforts to regain manual control, their attempts to override the autopilot failed. Unaware of the new steering control system’s requirement for aligning rudder commands at both control stations or holding down the takeover button for five seconds, they were unable to stop the ship from drifting off course.
Key Systemic Issues Identified
1. Steering Control System Familiarity and Procedural Knowledge
The Aratere’s steering update introduced several procedural changes, including the new Kongsberg control system’s dependency on aligned rudder commands between consoles. However, the bridge team did not appear fully trained in this feature, leading to a loss of control in an emergency. In particular, the lack of knowledge about the system’s “force takeover” function—requiring a five-second button hold to transfer control from autopilot—was a critical shortfall.
2. Autopilot Execution Commands and Navigational Timing
The incorrect timing of the “execute” command reveals a potential gap in the bridge team’s understanding or communication regarding the autopilot system’s requirements. The automated navigational path was predetermined and required precise inputs at specified waypoints. This incident demonstrates the need for a review of how these systems are configured and the importance of comprehensive training, particularly when crew members are transitioning back onto the vessel after time away.
3. Emergency Propulsion and Steering Coordination
As the Aratere continued its unintended turn, the Night Master attempted to put both engines into full reverse at 9:27:43 pm. Although the port and starboard propellers responded, there was a lag—21 seconds for the port and 38 seconds for the starboard—which delayed the ship’s ability to slow down in time to prevent grounding. In addition, the bow thruster was activated to assist in repositioning the vessel, but it was too late to avert impact.
Outcome and Immediate Damage Control
Despite the grounding, Aratere’s hull integrity remained intact, with damage limited to the internal structure of the bulbous bow, which needed repairs. There were no injuries to passengers or crew, and with coordinated efforts, the Aratere was refloated over the following two days with assistance from Picton harbour tugs.
Future Lines of Inquiry
The Commission has flagged several areas for in-depth investigation that could have wider implications for vessel operation and safety within KiwiRail and beyond. These include:
- Training and Familiarisation Procedures: The bridge team’s partial knowledge of the updated system’s operational intricacies highlights a need for enhanced familiarisation procedures when significant technical changes are introduced.
- System Compatibility and Configuration: The compatibility between the new Kongsberg steering control and the existing autopilot has raised questions about the challenges of integrating new systems with legacy components.
- Autopilot and Manual Control Transfer Mechanisms: With the bridge team experiencing difficulties transferring steering from autopilot back to manual control, a closer review of the ship’s command hierarchy and manual override procedures will be critical in preventing future incidents.
Awaiting Final Findings
As the Commission moves forward with its inquiry, it will compile a comprehensive analysis of the technical, procedural, and human factors involved in the Aratere grounding. The full report is expected to include recommendations aimed at addressing identified safety gaps and preventing similar incidents. KiwiRail, in cooperation with TAIC, will likely evaluate its current training protocols and control system interfaces to ensure that bridge teams can effectively respond to emergencies in complex, high-stakes environments.
The interim findings on the Aratere grounding underscore the importance of aligning human capability with technological sophistication in maritime operations. With the final report anticipated, both industry stakeholders and the public will be keen to understand the causes behind this event and the measures taken to reinforce navigational safety across New Zealand’s interisland ferry services.
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