It comes after the Herald reported this week on an assessment of the ferry fleet’s condition which said it would be an “ongoing battle” to keep the ships afloat. Concerns about steel corrosion, metal getting weak and cracking, and prohibitive maintenance expenses were raised.
The Herald has now obtained a summary of Maritime New Zealand’s investigation into Aratere’s power outage under the Official Information Act.
Aratere was approaching the entrance to the Tory Channel at 6pm with 538 people on board when it experienced a “power blackout”, the Maritime New Zealand summary said.
“This blackout only lasted a few seconds, before the emergency generator kicked in; however, the vessel was without propulsion and drifting at a location 3.42 nautical miles from the nearest point of land.”
Full propulsion was restored about 20 minutes later.
An Interislander investigation found the power outage was caused by the failure of a part in the diesel generator called an actuator.
A power blackout on board Interislander’s Aratere ferry was caused by disintegrating tape being used to hold wiring together. Photo / Maritime New Zealand
Interislander’s actuators are normally serviced internally by KiwiRail’s Hutt Workshops.
The decision was made to send the actuator to a repair centre authorised by the company that designed the part.
Technicians found some Spiraflex tape had been used inside the actuator.
“Over time this tape had degraded, causing debris to mix with the oil inside the actuator. The presence of this contaminated oil had caused the actuator to seize,” the report said.
Interislander Executive General Manager Duncan Roy said Spiraflex is the brand name for a plastic spiral product used for wrapping, securing, and protecting wires and the hydraulic hose.
It should not be used in oil-immersed systems, he acknowledged.
“Prior to the implementation in 2023 of our enhanced maintenance processes for Interislander’s three ships, the incorrect use of Spiraflex in an actuator caused a partial power outage on Aratere.
“Since then, and as part of the new processes, all our actuator overhauls are handled by certified manufacturers in Auckland and Australia.”
Transport Minister Simeon Brown says misters have been highly unimpressed with KiwiRail's maintenance of its Interislander fleet. Photo / Mark Mitchell.
Maritime New Zealand said in a statement its investigation determined that power was restored very quickly and there was no danger to passengers or crew.
“Once the investigation was completed, it was determined that the most appropriate course of action was to meet with KiwiRail staff to discuss the findings.
“As a result, KiwiRail implemented measures to prevent a similar occurrence in the future.”
Transport Minister Simeon Brown said both the Kaitaki and Aratere power outages have been attributed to maintenance issues.
“Since becoming Minister of Transport, I have made it clear to KiwiRail that the 2023 incidents were unacceptable and that I expect maintenance to be undertaken to a higher level to ensure the resilience of the inter-island connection.
“KiwiRail has provided both myself and shareholding ministers with assurances that improvements have been made to maintenance protocols.”
The latest incident involving the Aratere, when it ran aground on Friday, was due to a steering failure.
Brown said there will be several investigations into the grounding including by TAIC.
An expert Ministerial Advisory Group is working on the future of Interislander’s ageing fleet after the Government cancelled two replacement mega ferries due to cost blowouts.
Brown said the group will provide additional independent assurance and advice of KiwiRail’s work to operate, maintain and replace the fleet.
The group will recommend options to replace the ferries, he said.
“This work is progressing with urgency and Ministers will take recommendations to Cabinet.”
Georgina Campbell is a Wellington-based reporter who has a particular interest in local government, transport, and seismic issues. She joined the Herald in 2019 after working as a broadcast journalist.
