THE collision between US destroyer and an NYK box ship was the result of the USS Fitzgerald's bridge team's failure to take act moments before the 2,858-TEU ACX Crystal rammed the warship in approaches to Yokohama at 2am Saturday June 17.

"They did nothing until the last second," one official said. "A slew of things went wrong." A second official said the crash "will wind up being our fault". 

A preliminary inquiry into the accident said that USS Fitzgerald and a Philippine cargo ship said the accident was caused by multiple errors by the Fitzgerald's crew, according to two defence officials.

The collision claimed the lives of seven US sailors. It took place 56 nautical miles off the coast of Honshu, Japan in an area heavily travelled by commercial shipping.

The initial investigation found that the Fitzgerald crew failed to understand and acknowledge the cargo ship was approaching and failed to take any action necessary to avoid the collision. It's also not clear if the crew ever called the commanding officer to come to the bridge.

The officials say investigators are also looking at the possibility that the ship was travelling at a higher speed than expected in order to reach a location it was due to arrive at the next day.

"Heroic efforts prevented the flooding from catastrophically spreading which could have caused the ship to founder or sink," said Vice Admiral Joseph Aucoin at a press conference the day after the collision.

"The ship suffered severe damage rapidly flooding three large compartments that included one machine room and two berthing areas for 116 crew, " Admiral Aucoin said. 

"The commanding officer's cabin was also directly hit, trapping the CO inside." 

The ship's commander, Bryce Benson, was so badly injured that once freed he had to be medevaced off the ship by the Japanese Coast Guard.