There was nobody on the bridge of a cargo ship when it struck the USS Fitzgerald on Saturday claims one defense expert, as the US Navy and Japanese authorities clashed over the timing of the fatal accident.

As the official investigation over who is to blame for the collision which claimed the lives of seven US Navy sailors got off to a shambolic start, an expert with defense industry bible Janes said that the ACX Crystal was likely operating on autopilot and the crew was asleep.

And while the US Navy faces embarrassing questions over how one of their advanced $1.5bn warships was struck in near perfect visibility, it emerged that American officials are claiming the collision occurred nearly one hour after the Japanese Coast Guard say it did.

'I suspect, from the data, that the ACX Crystal was running on autopilot the whole time, and nobody was on the bridge. If anyone was on the bridge, they had no idea how to turn off the autopilot,' said Steffan Watkins, an IT security consultant and ship tracking analyst for Janes Intelligence Review, to DailyMail.com.

Course: This was the approximate route of the ACX Crystal before it collided with the USS Fitzgerald on Saturday morning - both ships officially reported a crash to the Japanese Coast Guard just after 2.20am on Saturday

Official time: The Japanese Coast Guard have said that the ACX Crystal collided with the USS Fitzgerald at 1.30am before the 30,000 ton cargo vessel began to perform a large U-turn - seen in red

Account: Following the collision at 1.30am the ACX Crystal was observed making a huge loop round which ended with it returning to the site of the accident with the USS Fitzgerald at 2.20am where they both reported their deadly crash

Seven US Navy sailors were killed in the collision, authorities have confirmed. They are (top row, left to right) Fire Controlman 2nd Class Carlos Victor Ganzon Sibayan, 23, from Chula Vista, CA; Gunner's Mate Seaman Dakota Kyle Rigsby, 19, from Palmyra, VA; Sonar Technician 3rd Class Ngoc T Truong Huynh, 25, from Oakville, CT; and Yeoman 3rd Class Shingo Alexander Douglass, 25, from San Diego, CA. Bottom row (left to right Fire Controlman 1st Class Gary Leo Rehm Jr., from Elyria, OH; Personnel Specialist 1st Class Xavier Alec Martin, 24, from Halethorpe, MD; and Gunner's Mate 2nd Class Noe Hernandez, 26, from Weslaco, TX

Coast guard official Tetsuya Tanaka said authorities are trying resolve what happened during the disputed 50 or so minutes.

Indeed, Navy spokesman Commander Ron Flanders added to the general air of confusion when he said that the official line is that the accident occurred at 2.20am.

When asked about the Japanese position that the crash happened at 1.30am, he said, 'That is not our understanding'.

Speculation has centered on why the USS Fitzgerald and its skeleton crew was struck on its starboard side in the early hours of Saturday morning.

Under international maritime rules, the Fitzgerald would be expected to give the ACX Crystal the right of way and real-time charts appear to show the Filipino-crewed vessel was sailing on that side.

This screenshot shows a track of the route of the container ship ACX Crystal that collided with the USS Fitzgerald: The track of the container shipís route by MarineTraffic shows it made a sudden turn as if trying to avoid something at about 1:30 a.m., before continuing eastward. It then made a U-turn and returned around 2:20 a.m. to the area near the collision

Heavy damage is pictured on the US Navy missile destroyer USS Fitzgerald after it collided with a cargo ship near Japan early on Saturday morning

On Saturday, both the US Navy and the Japanese Coast Guard said the accident occurred at 2.20am, leading to some experts theorizing that the series of unusual turns performed by the Crystal before that time may have caused the accident.

However, after interviewing the crews, the Coast Guard say the accident occurred at 1.30am and that the unusual maneuvers were the result of the Crystal returning to the scene to confirm a collision - and that is why it reported the accident at 2.20am.

Nanami Meguro, a spokeswoman for owners NYK Line told CBS News that one reason why the Crystal did not report the accident when it first happened was because it was all hands on deck.

'Because it was in an emergency, the crewmembers may not have been able to place a call,' she said.

However, the US Navy rejects this and says that the accident occurred at 2.20am and not 50 minutes earlier.

It is not clear why the US and Japan are disagreeing over the timing of the accident nor is it clear how the deadly collision occurred.

Multiple U.S. and Japanese investigations are under way on how a ship as large as the container could collide with the smaller warship in clear weather said coastguard spokesman Takeshi Aikawa.

Damage: The ACX Crystal reveals the damage caused by her collision with the USS Fitzgerald on Saturday

The victims might have been killed by the impact of the collision or drowned in the flooding, said Navy spokesman Lt Paul Newell, who led the media on a visit to get a firsthand look at the mangled destroyer. 'The damage was significant,' he said. 'This was not a small collision'

Listing: A shot of the ship's helipad shows how dramatically the USS Fitzgerald is listing after the accident

The impact of the collision crushed the starboard side of the Fitzgerald. The ship was visibly listing as it sailed into its home port in Yokosuka, Japan on Saturday afternoon.

Janes expert Watkins says that a sudden and unexplained U-turn observed on charts was performed by the ACX Crystal to see what had been hit - after human control was re-established on the bridge.

The Japanese authorities confirmed to DailyMail.com that they received the distress call from the Crystal container ship - which is crewed exclusively by Filipinos - at 2.20am local time.

But the owners, Tokyo based shipping firm NYK Line, told the DailyMail.com that the collision occurred at 1.30am.

The damaged US Navy destroyer USS Fitzgerald is seen berthing at Yokosuka Naval Base in Yokosuka, south of Tokyo

The discrepancies led to some media reports, based on the tracking of the Crystal, suggesting the Crystal had turned suddenly before the time the Navy insists the crash took place.

But the tracks of the merchant ship showed this was impossible, as the Crystal slowed just after 1.30am and then made a U-turn.

Commercial shipping can be tracked, such as the ACX Crystal, in real time via maps on maritime websites.

Steffan Watkins told DailyMail.com that the u-turn could have been carried out to find out what had been hit.

He stated: 'The collision happened at 1.30am, not 2.20am or 2.20am as the US Navy and the US 7th Fleet has mistakenly reported.'

A spokesman for the Pacific Fleet confirmed the Navy is sticking with its time of 2.20am for the time of the collision.

The damage to the destroyer suggests that the ACX Crystal might have slammed into it at a high speed, raising questions about communication between the two vessels in an area where as many as 400 ships pass through every day, according to Japan's coast guard

The container ship was seen making a U-turn before the collision on some ship trackers, a move that has raised questions about what happened. Both Aucoin and the Japanese coast guard, however, said it was too early to determine what led to the collision

After shifting through the data of the Crystals tracks at sea Watkins has concluded the cargo carrier mistakenly blindsided the Fitzgerald as the ship was without a human pilot at the time.

According to the the tracking data 15 minutes after the presumed 1.30am collision with the Fitzgerald, the ship righted it's course, and increased speed, readjusting for the change in course the collision had made.

'This is, to me, proof that a computer was driving. No captain shakes off a collision with a US Navy Destroyer and resumes course so perfectly,' said Watkins.

The company that charted the Crystal, NYK Line, confirmed to DailyMail.com that its offices received a call from to say they had hit something.

It wasn't until an hour later that the merchant ship informed the Japanese coast Guard.

'After further review of all the data and their own information (I am not privy to what sensors and transponders they might have) I'm sure the US Navy knows by now the hit was at 1.30am, but is in a difficult position to explain that time difference,' said Watkins.

A screenshot provided by vessel-tracking service MarineTraffic shows a track of the route of the container ship ACX Crystal that collided with the USS Fitzgerald in the waters off Shimoda in the Izu Peninsula, southwest of Tokyo

'Not calling it in until 2.25am is unbelievable unless you consider they had no idea what they hit until 2.25am.

'It is unconscionable to think a 30,000 ton vessel collided with, and could have utterly destroyed, another vessel, and waited an hour to call the Japanese Coast Guard and report the collision.'

So far there is nothing to indicate how two well equipped vessels could not avoid one another.

Scott Cheney-Peters, division officer aboard the Fitzgerald 2006-2008, suggested the accident was down to human error.

The coast guard questioned crew members of the ACX Crystal, and is treating the incident as a case of possible professional negligence, said Masayuki Obara, a regional coast guard official

'There's a lot that can go wrong even when the bridge team one or both ships is doing everything it can to avoid a collision. It's too early to speculate on the exact circumstances in this case so this is only to help understand the context,' he told Mailonline.

'The first thing to remember is the physics - ships can carry an immense amount of momentum with them given their size.

'Every time two ships approach each other at sea they rely on codified rules of the road to govern how they perform their delicate dance.

'But making sure they get the steps right depends on a shared understanding of the situation - which can be more difficult at night - and failing that, communication.'

The US Navy and the Japanese authorities, and NYK have declined to comment on aspects of the ongoing investigation, nor has an explanation been offered as to why USS Fitzgerald did not see the ACX Crystal coming and vice versa.

All parties have refused to discus the investigation which they say is still ongoing.

According to Japanese law suspects in criminal proceedings, such as these, can be held for at least 23 days without charge and without access to lawyers.

The coast guard declined to confirm if they were still questioning the Philippine crew and captain in Yokohama with the Crystal in now berthed.