The Interislander ferry Aratere is being investigated by the Transport Accident Investigation Commission after an eight-hour journey in stormy seas on Friday that injured passengers and damaged cargo.
The ferry sailed across the Cook Strait through 10m swells and 125km/h winds.
Chief investigator John Mockett said the decision to sail
led to the injuries and damage.
The ordeal for the passengers and crew began around 2pm and the ferry limped into Picton about 10.30 - five hours later than scheduled.
"What we're looking at in the investigation is the company policies on whether or not they should sail, the decision to sail that was taken on the night, and then having made that decision, the security of the cargo," Mr Mockett said.
Six rail wagons fell over and heavy trucks and vehicles moved around, causing considerable damage, he said.
"Large items of cargo moving around in any ship can be dangerous for the personnel on board and we felt that was worthy of an investigation."
Mr Mockett said heavier vehicles, wagons and campervans were tied down, but the investigation team would look at how they were secured - the adequacy of it, the policy and the strength of the lashings that they used.
He added that the investigation would also cover how people on board the ferry were injured.
"We understand initially, and remember it's very early days, that one crew [member] and three of the passengers received injuries."
Ferry owner Toll said it had reported the incident to the commission and was co-operating with the investigation.
- NZPA
