I heard it was 8 knots, but even 7 knots for a ship of that size at that distance from the bridge was a criminally negligent speed, especially since they were not even in clean lane to clear the bridge if they lost propulsion/steerage. Too close, too fast. Stupid trajectory for the mass and speed of the ship.
Boiled down: This whole FUBAR is PILOT ERROR, by the ship's captain, and the two 'harbor pilot experts'.
The mechanical failures are beside the point. The crash happened because the PILOT'S F'D up.
I was amazed at how quickly the bridge completely collapsed after impact; a very few seconds. Nothing 'slow motion' about it.