Damage to the hulls of two vessels during the past week are the latest in a series of disruptions, delays and cancellations to Cook Strait ferries this year.
KiwiRail, which owns the Interislander ferry service, said the Kaiārahi was damaged on Sunday when it came into contact with a fender on the wharf, leaving a metre-long hole in the hull. Bluebridge also reported a hole in the side of one of its ferry's hulls on Wednesday after it hit a wharf in Wellington.
This year, Interislander and its competitor Bluebridge (managed by StraitNZ and owned by New York-based investment fund Morgan Stanley) have both faced recurring mechanical challenges, with many sailings cancelled and passengers reporting difficulty getting alternative bookings.
During one January sailing, the Interislander's Kaitaki ferry lost all power from its engines in rough conditions and drifted dangerously close to Red Rocks on Wellington's south coast, with more than 800 passengers and 80 crew on board. After about four hours without power, tug boats accompanied it into Wellington Harbour and multiple investigations were launched.
And the disruptions could be ongoing, as some vessels in the Interislander fleet are reaching the end of their expected 30-year lifespan, but the first of their new replacement ferries are not expected to be ready until 2025.
RNZ has put together a timeline of the breakdowns of the Cook Strait ferries this year.
Kaitaki lost power amid 3m swells and high winds off Wellington's south coast, and drifted nearly a mile off course, with about 880 people on board.
The crew managed to restore power, to slowly sail into the harbour about seven hours after leaving Picton.
The fault was later identified as a leak in the cooling system due to an old engine part that ruptured.
Thousands of passengers who had planned to cross Cook Strait with the two ferry services found their plans grounded, after sailings were cancelled for Bluebridge's Connemara and Interislander's Kaiārahi due to "engineering issues", and the Interislander's Kaitaki was limited to only carrying freight after January's incident where it lost engine power.
Some passengers reported multiple bookings were cancelled and they were not able to rebook. Bluebridge said due to the lack of alternative sailings, its only option was to refund those affected.
Kaitaki was taken out of service after new engineering problems with its gearbox.
The repair took more than a month and a media release by Interislander said it was a complicated process, requiring parts to be shipped from Germany and specialist support from the Netherlands. The ferry was back in full service by 12 April.
On 3 April Bluebridge cancelled multiple sailings of the Strait Feronia for two days, due to engineering faults. However it had no space for any more vehicles on its other sailings within a few weeks of the cancelled services.
Meanwhile, the Interislander's Kaitaki was unavailable for part of the month due to gearbox issues.
On 9 August, a small number of passengers were forced to spend the night on the Kaitaki anchored in Wellington Harbour, after it had been forced to turn back from a sailing due to steering issues. An Interislander spokesperson said the ship retained steering control through backup systems.
Sailings of the Kaitaki were cancelled on 22 August after a bow door was damaged by a large wave during a crossing. KiwiRail said during predeparture preparations for another sailing it was found the door could not realign before closing. It was back in service the next day following repairs.
On Wednesday 8 November, Bluebridge's Connemara hit Glasgow Wharf as it was leaving Wellington, and was turned back before passengers were disembarked. The incident left a "decent dent" on the hull and a small hole above the waterline. Engineers were assessing the damage to the wharf.
On Sunday 12 November, Interislander's Kaiārahi was damaged during berthing, leaving a 1m-long hole in the hull.
Wellington harbourmaster Grant Nalder said while it "looks quite dramatic" and was not good for the ship, the hole was high up on the hull away from the waterline. But he did not have a good reason why there had been two incidents a week apart.
He said the ship landed in a different place than usual with "a bit more force than intended", and it had been gusty.