A container ship which spent weeks detained in Wellington harbour following a breakdown has put out a mayday call as it lists in “rolling seas” off the coast of the South Island.

Multiple helicopters and a Defence Force Hercules have been sent to the site after the Shiling lost power 22 nautical miles from Farewell Spit.

“The Shiling container ship is drifting in rolling seas after losing power,” said a New Zealand Defence Force spokesperson.

“At the request of the Rescue Coordination Centre, a C-130 Hercules aircraft has been diverted from an exercise to assess the situation off Farewell Spit.

“An NZDF liaison officer is providing assistance to the Rescue Coordination Centre, and an RNZAF NH90 helicopter is on standby prepared to respond if requested.”

Maritime NZ’s Rescue Coordination Centre is responding to a mayday request from the Singaporean cargo vessel Shiling, a spokesman confirmed.

“It put out the mayday call about 11am, May 12. It initially put a request through for assistance at 8.27am,” Maritime NZ said in a statement.

“The vessel is situated 22 nautical miles north northwest of Farewell Spit.”

They are in communication with the vessel and an ocean-going tug from Port Taranaki has been dispatched to tow the ship to a safe location.

Container ship the Shiling has put out a mayday call as it lists off the coast of the South Island. Photo / MarineTraffic.com

The tug is expected to reach the Shiling’s location by 4pm today.

“Due to where the vessel is, there is no risk of it running aground prior to the arrival of the ocean-going tug.”

There are 24 crew members on board the ship.

Maritime NZ’s Rescue Coordination Centre has Police, Coastguard, and St John Airdesk on standby and will be using them as required.

The Shiling recently broke down in Wellington’s main shipping channel, making it the third incident involving the same vessel in less than a year.

The cargo ship had been departing Wellington for Napier when it had a power failure and began drifting, having to drop two anchors to come to a stop.

When the breakdown happened mid-April, Maritime NZ imposed conditions on the Shiling prohibiting it from leaving Wellington Harbour until all power generators and the main engine were fully operational to the satisfaction of the vessel’s Classification Society.

The Singapore-registered ship was finally able to leave Wellington this past Wednesday, but just days later has broken down again.

A Transport Accident Investigation Commission [TAIC] spokesman said they were aware of the incident.

They were “gathering further information to inform a decision on whether to investigate”, spokesman Simon Pleasants said.

TAIC chief commissioner Jane Meares said she was not aware of a mayday being issued, but was aware the Shilling had encountered an issue.

“We’ve certainly had a reported incident. We’re monitoring the situation and seeing if it’s more appropriate to investigate.

Chief investigator of accidents Naveen Kozhuppakalam said the vessel was listing after encountering some type of problem 20 nautical miles off the coast.

On July 4 last year the ship suffered engine failure in Wellington Harbour. Maritime NZ imposed conditions preventing its departure until repairs were carried out.

And on February 11 this year it had a brief engine stoppage in Wellington Harbour.

Wellington regional harbourmaster Grant Nalder raised concerns with Maritime New Zealand about the Shiling after its third breakdown.

“This is the third time, which I’m not happy about and they are looking very carefully at the ship.

“I understand she hasn’t had any problems in any other New Zealand ports but I’m concerned that this has happened again.”

The latest breakdowns come as Cook Strait ferry operators Interislander and Bluebridge recover from a disastrous summer, with multiple breakdowns, engine problems and cancellations.

Interislander’s Kaitaki ferry resumed passenger services last month after effectively being out of action for more than two months.

On January 28, the ship declared a Mayday with 864 people on board when it lost power in Cook Strait and started drifting towards Wellington’s south coast.

After being given the all-clear to take passengers again for the first time in five weeks, Kaitaki was back sailing for less than 24 hours before a problem with its gearbox was discovered on March 4.

Interislander executive general manager Walter Rushbrook said the gearbox repair has gone well.

“The Kaitaki repair was complicated, requiring a particular type of metal for the gearbox that was manufactured and shipped from Germany, along with specialist technical support from the Netherlands. The gearbox failure was a surprise, given it was overhauled late last year in drydock.”

Two new mega-ferries are being built at Hyundai-Mipo Dockyard in South Korea to replace the increasingly unreliable Interislander fleet. They are due to arrive in 2025 and 2026.

- Melissa Nightingale and Vita Molyneux, NZH