Interislander’s Kaitaki ferry will resume passenger sailings tomorrow, five weeks after it lost power and issued a mayday call in the Cook Strait.

All four engines on the Kaitaki shut down on Saturday, January 28, and the ship drifted a nautical mile (1.8km) towards Wellington’s south coast before the ship’s anchors held and power was able to be restored.

Both Interislander and rival operator Bluebridge have been hit with breakdowns and engine problems in recent weeks, disrupting the travel plans of thousands of passengers.

Interislander executive general manager Walter Rushbrook said since the mayday incident, several assurance processes had been undertaken to confirm ferries in the fleet were safe to sail.

”We have also had a number of independent checks undertaken. The maritime industry is highly regulated, so it is not our decision alone to sail the ships.

”We have had the all-clear from surveyors from our Class Authority, our team has been through all our ferries checking parts and systems, and we have worked closely with the regulatory authority, Maritime New Zealand.”

The Kaitaki has been doing freight-only sailings for the past month and Rushbrook confirmed passenger trips would start again tomorrow.

The full return of the Kaitaki will help ease pressure on the troubled Cook Strait services.

Rushbrook said safety was Interislander’s first priority and they would not be sailing the ship unless they were confident it was safe to do so.

The Transport Accident Investigation Commission has also opened an inquiry into the breakdown.

Since the incident, Bluebridge and Interislander ferries have both been hit with further breakdowns and engine problems.

Multiple sailings have been cancelled and thousands of passengers left stranded as both ferry operators are booked to capacity until mid to late March.

”The past few weeks have been rough for our customers, for our passengers and for our own people who have been working above and beyond to get as many people and as much freight as possible across Cook Strait,” Rushbrook acknowledged.

Interislander’s two new rail-enabled mega ferries are due to arrive in 2025 and 2026.

These would be a game changer for reliability, carbon efficiency, comfort and on-board passenger services, Rushbrook said.

“Until they arrive, we will remain focused on providing a safe, reliable service that earns the respect of customers and passengers.”