I seem to recall that those US ships can accelerate remarkably fast for their size and to a speed over 30 knots. 

USN sailors are usually pretty competent folk, it seems, so I am surprised that they would get hit if they could avoid doing so. Why they could not avoid doing so remains to be seen I suppose.

From the Telegraph (note - I suspect they meant "have been found on board..." but they fired their sub editors ages ago and it shows.)

Bodies of seven sailors reported missing after the USS Fitzgerald collided with a container ship have been on board the destroyer, the US Navy said.

The bodies were discovered after U.S. and Japanese vessels and aircraft spent Saturday searching for the American sailors.

They were feared lost after their Navy destroyer collided before dawn with a container ship four times its size off the coast of Japan.

The Navy says in a statement that searchers had gained access to the spaces that were damaged during the collision.

From NBC: Bodies of 7 missing US sailors found in destroyer damaged by collision. This confirms the above, with more details.

lets be clear in a collision at sea the maritime rules say both vessels are at fault as the very first rule is that you must take avoiding action to avert any colision !

However looking at the immedate damage photos it appears the container ship has damage to its port bows and the the warship has damage midships on the starboard side so .......the warship would appear to have been the giveway vessel here at first glance.

edited for spelling and sense

unless they were being over taken and the container ship veered into the destroyer

How do container ships run over charted reef's outside Tauranga?

Looks like some erratic driving in a high traffic area leading up to it. I would love to know the reason for that.

War Ship won't have been at action stations (as evident by "most of the crew being in bed") so their lights would/should have been on and their fancy radars off.

They tend not to have their Military style Electronic Surveillance running in friendly foreign waters, closed to land for several reasons:

1) It can been seen as quite offensive to the friendly host nation to be in battle mode/intelligence gathering mode.

2) You un-necessarily give other people the opportunity to gather electronic information on the ship and establish electronic signatures etc.

3) When the ship is emitting lots of radio signals it effectively announces the presence of the ship & makes it easier for the baddies to track the ship via satellite etc.

4) When close to land and in/near a foreign country the radars & countermeasures systems can interfere with or jam lawful radio/cellular/radars (due to thehost/guest countries conflicting/differing rules on frequency allocations, and the very nature of the warships equipment) which is also an unfriendly and un-necessary thing to do.

Edit: Spelling, and I probably still didn't fix it all.

Seakiwi:

lets be clear in a collision at sea the maritime rules say both vessels are at fault as the very first rule is that you must take avoiding action to avert any colision !

 

Did the merchant ship have a pilot* on board? 

The U turns could be explained as turning the ship around so the local pilot can board from the sheltered side.

* pilot in this context is a mariner employed by a port to navigate ships in and out of the port.

"The US Navy said the collision happened at about 2.30am local time, while the Japanese Coast Guard said it was 1.30am local time."

I think there's a New York Times report showing the collision occurring before the freighter changed course turning back then resuming.

MikeAqua:

 

Did the merchant ship have a pilot* on board? 

 

The U turns could be explained as turning the ship around so the local pilot can board from the sheltered side.

 

* pilot in this context is a mariner employed by a port to navigate ships in and out of the port.

 

Wouldn't there be a lee side regardless (more or less) of the direction of travel with only a small course correction rather than a complete U turn?

Bung:

 

"The US Navy said the collision happened at about 2.30am local time, while the Japanese Coast Guard said it was 1.30am local time."

 

I think there's a New York Times report showing the collision occurring before the freighter changed course turning back then resuming.

 

Does the freighter course change resemble one enacted for MOB recovery?

It is now pretty clear that the collision happened at the first course change to starboard by the commercial vessel and the course reversal was them returning to the point of collision to render assistance. 

Strangely, neither vessel seems to have reported the collision to the local Japanese authorities for 55 minutes.

Still pretty hard to see how it wasn't the warship primarily at fault here given the photos of the damage on the port bow and starboard midships.

The MOB would have to be able to swim. The freighter turned right (South) briefly before continuing East for about 30 mins before turning back to the collision point then another u turn back onto its original course about 4.30am. The Japanese Coastguard say the original time was reported as 2.20am because the Crystal reported at 2.25am. 

Something seems screwy if the US Navy didn't immediately correct the time or confirm the earlier report.

Looking at the original Google Map posted here, I see the container ship initially following a blue dashed line, presumably a standard shipping lane or such-like? Then it turns left and collides with the warship.

I'm thinking/speculating that (a) someone on the container ship dozed off, then belatedly realised they should have turned left several minutes ago to stay in the shipping lane, and (b) on the warship, people are comfortably dozing along, in the knowledge that they are well clear of the shipping lane.