This video by a passenger aboard the cruise ship Carnival Vista provides a good view of the moment the giant cruise ship destroyed a marina as it departed Messina, Italy in August.
As you can see from this view it looks like wind may have played a factor, pushing the cruise ship to within just feet of the small marina before the Captain fired up the thrusters to back the ship off the docks. Unfortunately the thrust was so much that the prop wash acted as a small tsunami swamping boats and overturning piers at the marina.
This incident could have been prevented if – instead of using the ship’s massive thrusters to make the turn – the Captain had called a tugboat to push the ship around the bend.
gCaptain’s earlier reports on this incident: