US investigators say too soon to know what caused tanker-cruise ship collision

The US National Transport Safety Board (NTSB) says it is on a "fact finding" mission to figure out how a tanker collided with a cruise ship that had more than 100 passengers.

All 197 passengers and crew on the American Heritage cruise ship and tanker survived the collision in New Orleans on Friday, local time.

Officials said 32 people were taken to hospital, including two police officers thrown into the Mississippi River when the boat rolled, but none of the injuries were critical.

Eight remained hospitalised on Saturday.

The National Transportation Safety Board said the tanker's voyage data recorder had been recovered, and a 16-member team would spend a week in New Orleans investigating the incident.

NTSB member John DeLeeuw said the agency expected to release a preliminary report within 24 to 30 days, with the final investigation report expected in 18 to 24 months.

“We are still in the fact-finding stage. We look at the maintenance record, the history of the ship. We actually look at a number of things, but it is way too soon [to know what happened]," Mr DeLeeuw said.

Survivor recalls harrowing minutes in river

The first warning Joe Knab, a passenger on the American Heritage cruise ship, had of the imminent collision was the tanker blasting its horn several times.

The hit was hard, and the cruise ship immediately started leaning. The crew quickly gathered everyone on the third deck, got them in life vests and started getting them off the boat. 

But the vessel suddenly rolled and sent Mr Knab and about 100 other passengers and crew into the muddy Mississippi River.

Tugboat operators, other cruise ship captains, nearby workers, police and other rescuers rushed to help.

"It's fine now, but it was a little scary there at the time," Mr Knab told WDSU-TV, still in the jeans he was wearing on the boat, now covered in mud.

"I thought I was drowning because I kept bobbing underneath — and the water doesn't taste very good."

Mr Knab was wearing a shirt from a Hilton hotel where the passengers gathered after the incident. The rest of his belongings were in the river but somehow his phone still worked.

He said he was in the water for about 15 minutes, and joked that his 20 years in the navy likely helped him.

"They taught us not to drown," he said.

Lawsuit leads to warrant to get control of tanker

A lawsuit, filed by the Board of Commissioners of the Port of New Orleans, said the Atlantic Asphalt tanker caused at least $US1 million ($1.47 million) in damage to its terminal. 

A judge issued a warrant on Friday giving federal officials control of the ship for now.

The tanker has been towed away from the site, but it could take weeks to move the cruise ship, which remains on its side against a terminal in the Mississippi River, Coast Guard Captain Melanie Burnham told reporters on Saturday.

She said the first step was to make sure the 60,500 litres of fuel on the boat were removed safely.

Traffic has been limited on the Mississippi River, but Captain Burnham said boats should be able to move both upstream and downstream soon.