Despite the incredulous nature of these incidents, I don't think you can rule out the  deliberate aspect and it still needs to be considered and investigated.  Would a  terrorist organization or a rogue state use such a method to disable and take out of commission one of our most powerful and needed warships?  It is still possible and perhaps the crew on the other ships involved might sacrifice their careers to make a political statement if so radically motivated and if they will be paid under the table later.  Call me paranoid, but stranger things have happened.  Also, how come no injuries on the other ships?  As if they were anticipating the collisions?  Maybe the Navy brass needs to take a closer look at the assumption that their people were exclusively at fault.  Not the first time crew were "railroaded" to excuse the higher command.