The Transport Accident Investigation Commission of New Zealand (TAIC) has released its updated report on the investigation into the grounding incident involving the Ro-Pax ferry Aratere near South Island on June 21, 2024.
Shortly after departure from Picton, the ship’s pilot engaged the autopilot and pressed the "execute" button expecting the steering system to make a programmed three-degree right turn. However, the ship had already passed the programmed waypoint for that small turn, so the autopilot locked onto the next waypoint and made a much larger 34-degree right turn.
The bridge team responded quickly and decisively upon realising the vessel was deviating from the passage plan. They were unable to regain steering control because they were unfamiliar with procedures for the ship’s newly installed steering control system that differed from the old system.
They sought to stop the ship using reverse thrust. While slowing, the vessel grounded.
Aratere’s watertight integrity was not compromised and in the following two days, Aratere was refloated with the assistance of harbour tugs. The grounding dented the bulbous bow and damage to the internal structure required repair before the ship’s return to service.
There were no injuries.
TAIC said the operator had installed a new steering system, focusing mainly on physical installation of the equipment, treating it as a like-for-like replacement, which it wasn’t. However, the change management process was not robust, so operational differences between the old and new systems were not fully identified before the vessel returned to service. Also, sea trials, evaluation, and training did not adequately test or address those differences.
Safety audit and assurance checks were not being properly carried out, so shoreside management lacked visibility of day-to-day practice on the bridge drifting away from ideal. Safe navigation procedures were described in the operator’s safety management system and were available for the bridge team, but implementation was inconsistent. Hazard controls intended to prevent exactly this type of occurrence – such as challenge and verification, role definition, and good communication – were operating but not effectively enough at the time of the grounding.
TAIC also found that the bridge team had not received training on two safety-critical operational differences: first, that to transfer steering control from one command console to another, rudder command settings on both consoles had to be aligned within two degrees; and second, that a force takeover function could override this requirement.
TAIC said that KiwiRail, via its Interislander operating arm, has addressed both issues. They have: revised bridge resource management training; updated navigation assessments; improved management-of-change processes; and developed ship-specific steering system guidance and training. As a result, there was no need for the commission to make recommendations.
The report carries four lessons for anyone responsible for workplace safety.
TAIC has advised that if one modifies a safety-critical system, one should analyse the risks, follow change management processes, and do the training to address operational differences from previous systems.
Also, crews must consistently apply procedures for teamwork and good communication and safe navigation to interrupt small errors before they escalate into serious accidents.
Quality assurance programmes, such as audits and assessments, are part of ensuring safety-critical procedures are consistently and fully implemented. Lastly, safety-critical upgrades succeed when responsibility, change management, and return-to-service testing are clear.
