A degraded and overdue component caused the loss of power on Interislander ferry Kaitaki, which drifted towards rocks off Wellington in 2023, a Transport Accident Investigation Commission (TAIC) report has found.
The incident occurred on January 28 when the vessel suffered a total blackout near Sinclair Head while sailing from Picton to Wellington, losing propulsion and electrical power in rough conditions.
TAIC says the ferry drifted towards a lee shore for about an hour before anchors slowed its movement, with propulsion eventually restored and tugs escorting the vessel safely to port.
The report found the blackout was caused by the failure of a rubber expansion joint in the engine cooling system, which ruptured and drained most of the cooling water, triggering an automatic shutdown to protect the engines.
The component had exceeded both its recommended service life and age limits. It was already 13 years old when installed in 2018 and 18 years old when it failed in 2023, despite manufacturer guidance that such parts should be replaced after five years.
TAIC identified six safety issues arising from the incident, including the management of safety-critical components, emergency response coordination, evacuation planning for older vessels, and limitations in New Zealand’s salvage and towage capability.
The commission found the ferry’s cooling system represented a single point of failure, highlighting the importance of maintaining and replacing critical components in line with manufacturer guidance and risk management systems.
It also found onboard engineers lacked structured decision-support tools, which may have delayed restoration of power, and recommended improvements to training, planning and emergency response systems.
The report raises broader concerns about ageing vessels operating in New Zealand waters, noting evacuation planning standards for older ships may not reflect current risks and should be updated to align with modern international guidance.
TAIC also identified gaps in coordination between responding agencies during the incident, with different organisations not sharing a common understanding of the situation as events unfolded.
In addition, the commission highlighted the lack of dedicated emergency towage and salvage capability in New Zealand, warning this increases the risk of serious maritime incidents involving disabled vessels.
TAIC has made a series of recommendations aimed at improving system-wide safety, including stronger maintenance oversight, better emergency preparedness, clearer response coordination, and ongoing work to strengthen salvage and rescue capability.
The commission says the Kaitaki incident demonstrated how a single component failure can escalate into a major safety risk, particularly in challenging operating environments such as Cook Strait.
