The Bluebridge ferry Connemara has arrived back in Wellington, about five-and-a-half hours after it lost power and started drifting in Cook Strait.
Wellington Harbourmaster Grant Nalder said it blacked out around 10.30pm on Thursday, not long into its freight sailing bound for Picton, near Sinclair Head.
By 2am Friday, the tug boat Tapuhi was towing Connemara back to Wellington, and a second tug, Tiaki, was providing steerage. By 6am it was towed to Pipitea Wharf. Reporters at the scene said people had begun getting off the boat about 7.30am.
Minister of Transport Simeon Brown told RNZ the vessel would remain in dock until the MNZ investigation was completed.
Nalder said Connemara had 88 people on board, and although the situation was not a rescue, Maritime New Zealand and the Rescue Co-ordination Centre had been keeping an eye on them.
Bluebridge says that included 24 passengers, 13 freight drivers and crew onboard.
Nalder told Morning Report that because the vessel was drifting southeast away from land, it was easier for the tug boats to reach it, and the situation did not have same urgency as when the Kaitaki lost power in January with more than 880 people on board and drifted towards the South Coast.
Last night, it "probably took a bit longer than usual to tie up" the Connemara because the mooring winches used power, but "a lot of work went on overnight to bring her back safely", he said.
It was not yet known why the power went out, he said, and Maritime New Zealand would be investigating.
RNZ asked Nalder if there had been any risk of the Connemara hitting rocks if the wind and current had been in a different direction.
Nalder said after the Kaitaki lost its engines in a stronger southerly, ferries had been sailing further south to create a buffer and extra time in case of a similar issue.
"Last night was quite light winds, so even if it had been from the south she would have been drifiting a lot slower than the Kaitaki would've."
Asked if passengers should be concerned after years of issues with the Cook Strait ferries, Nalder said both companies worked hard to keep them running.
"It is a concern - as the ships get older, that concern goes up a bit more, and the fact we don't have great support for them out in Cook Strait..."
After the Kaitaki stranding, CentrePort had put a second tow line on tugs that was more suitable for open-water towing, and he assumed that was used last night.
"They did a brilliant job."
Ferry troubles 'concerning' - Minister of Transport
Speaking to RNZ, Brown said he had been briefed on the "unfortunate incident".
"Thankfully, everyone is safe and the ferry is back in the Wellington port."
The string of incidents was "concerning", Brown said, but ultimately MNZ had to conduct its investigation to find out what happened.
"I'm advised the vessel won't be allowed to go back into service until MNZ has investigated and is assured that it is safe for it to do so."
In this year's Budget, MNZ had been asked to undertake a business case for an open-water tug service to assist in such circumstances, he said.
"Obviously, that is not something that we take lightly but it is something we have allocated funding for ... that work is underway with MNZ leading that with the Ministry of Transport."
String of issues
Both the privately owned Bluebridge and the state-owned Interislander have had engine failures in their ferries this year.
In May, passengers on board a different Bluebridge ferry, Strait Feronia, were briefly plunged into darkness when their ship lost power coming into Wellington Harbour.
In 2023, the Connemara hit a wharf while it was leaving Wellington, causing a "decent dent" on the hull and a "very small hole" above the waterline, Nalder said at the time.
The vessel returned to port and passengers were able to disembark safely.
The Connemara underwent repairs and was back in service later that day.
Interislander ferries have also been plagued by issues in recent months - most notably the grounding of the Aratere near Picton in June.
The ferry, which was on a crew-only sailing, ran aground after a staff member mistakenly changed its course.
StraitNZ Bluebridge spokesperson Will Dady said there was no immediate threat to those onboard the vessel or to the vessel itself while it drifted overnight.
'"Tugs were quickly dispatched to assist the ship safely back to Wellington, while the ship's engineers worked to understand and resolve the issue."
"Everyone on board was very calm, with lighting restored almost immediately. The crew responded well to a situation for which they are trained."
Dady said the Connemara sailings on Friday at 0815 from Wellington and the 1400 from Picton had been cancelled.
The company would now begin an investigation to establish what caused the issue.