An interesting FB comentary from a retired marine engineer, at least from looking at the released footage.
It looks like they set the ship up for a turn after the power came back on after the first blackout, then they lost power for the second time. The rudder was hard down for the turn, maximum power on the prop. The ship was aimed for the middle of the span, when the power went down for the second time, lots of energy in the turn and the rudder was locked hard down from the lack of power....
No way to steer without power. Possibly primary and backup power systems malfunctioned (my thoughts). It was a case of cascading failures.
When was the last time this ship was inspected.