The Truck Trailer that Went Overboard on the Cook Strait Ferry

A trailer containing chilled goods was lost overboard in Cook Strait this morning.

Following the incident the ship continued on to Wellington.

Strait Shipping general manager commercial Ed Menzies said they are not sure how the trailer came off.

"The unit was storm lashed and it is unclear as to why it moved and broke the ship's railing, and the company has launched an immediate investigation into what happened.

Maritime NZ officials inspecting the damaged onboard the Bluebridge Cook Strait ferry Straitsman after a truck tumbled off it's deck. Photo / Mark Mitchell

"Strait Shipping has not had an incident of this nature before."

This afternoon's sailings of the Straitsman have been cancelled.

Passengers have described rough seas and huge waves as the unit went overboard.

A passenger on the Bluebridge Straitsman ferry heading from Picton to Wellington which departed at 8am this morning said the truck went over the side of the ship about 10.30am.

Mariia Hakala said the sea was rough when the trailer went overboard.

"There were a lot of waves. There was a side wave and it made the boat go sideways.

"The next thing I know, people were saying a trailer had fallen into the water."

Ms Hakala was sitting near the kitchen when it happened.

"I could hear a lot of stuff falling down in the kitchen."

Ms Hakala said many passengers were vomiting.

"It was really hard to walk inside because the waves were really high. People were throwing up."

She said crew gave the passengers paper bags and ice cubes.

MetService meteorologist Peter Little said gale-force winds had ripped through Cook Strait this morning, causing choppy seas.

"We've had a gale there, and there's been waves of four-and-a-half metres, and up to about seven metres occasionally."

- NZ Herald