I'm sure we'll learn more in the coming weeks. My guess is a mix of human error and possibly equipment failure. Maybe the destroyer had a green ensign standing his or her first watch alone on the bridge (it was the middle of the night) and called out the wrong directions when things got critical. The freighter may have had an equipment failure that had it running blind.
Occam's Razor is usually the best explanation for these things. Actually finding a US destroyer in the middle of the ocean, then managing to run it down with a much slower and less maneuverable ship is a pretty unlikely scenario. If a crazed merchant captain was trying to ram another ship, he or she would either do it in port with a stationary warship, or it would likely go down as a close call on the high seas and the Japanese coast guard would be opening an investigation that could result in the captain losing their license for no gain.
There are lots of ways to damage US warships if somebody really wanted to. Doing it with a merchant ship at sea is one of the least effective unless you have a Q ship.
A few comments on the accident.
The extent of the damage is due to the freighter having a bulbous bow. You can't see the extensive damage done to the DD below the water line.
A U turn for a slow large freighter might be unusual but can't be called radical. Slow large ships really can't make a radical turn.
U turn or not, the positioning of the ships and the area of the collision suggests that the freighter had the right of way.
The investigation has now determined that the U turn happened after the collision-probably in an attempt to assist after the fact.
In some ways, Cronin said, it didn’t matter who had the right of way in this case. “In my mind, our destroyer is a more capable, agile ship, so regardless of who has right of way, our ship should be able to take evasive action,” he said.
A modern DD has a bridge watch of multiple men while a cargo ship will have two or three-if the captain is present. Even if the cargo ship is found to be at fault, (which I doubt) the careers of the captain of the DD and every officer on watch at the time are pretty much in the toilet. The Navy will find no excuse for a highly maneuverable warship to not recognize and avoid the danger of an immediate collision by a slower and less maneuverable ship.
The only exception would be major equipment failure. That happens at sea more than we would like to think.
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