Aratere ferry back in the freight business

The Aratere appears out of the fog on its arrival at Wellington Harbour. Photo / File / Mark Mitchell

The issue-plagued Interislander ferry Aratere will operate a freight-only service from today using its one remaining propeller.

The KiwiRail-owned ship has been out of action since it lost one of its two propellers during a Cook Strait crossing on November 5.

Interislander general manager Thomas Davis said classification society Det Norske Veritas (DNV) had granted safety approval for the Aratere to operate as a single-shaft, freight-only service during its busy summer period.

The ship will make daily return trips from Wellington to Picton from today until Christmas Eve.

DNV had reviewed ultrasonic tests on the port propeller shaft to ensure there were no issues, and a thorough risk assessment had been carried out, Mr Davis said.

He said the operating plan and timetable had been worked out along with DNV, Maritime NZ and harbour masters in Wellington and Marlborough.

Last month, KiwiRail chartered Spanish ferry Stena Alegra to replace passenger and freight services during the busy summer period.

Mr Davis said the Aratere's extra freight service would provide an improved opportunity to move more freight during the busy period.

"The ship will be able to carry 32 rail wagons and 28 trucks per sailing which will mean about 300 trucks that wouldn't have been able to cross Cook Strait will now be able to do so, allowing space for passenger vehicles on both the Kaitaki and the Stena Alegra.''

Mr Davis said plans to minimise risk included the use of tugs to escort the Aratere in the enclosed waters of the Marlborough Sounds. Tugs would also be on standby in Wellington Harbour and would help the Aratere into berth.

Navigating the sounds, the ship would sail via the northern entrance of Queen Charlotte Sound, rather than the narrower Tory Channel.

Mr Davis said there would also be restrictions on sailing when the significant wave height was above 3 metres or the average wind speed at berth was above 20-25 knots.

The Aratere recently underwent a $54 million revamp, but has been plagued with problems in recent years.

In January, a computer issue affecting propulsion took it out of action, and engine problems put a stop to passenger sailings for more than a week in 2011.