Two longshoremen were killed in St Kitts when their boat capsized while an unmooring maneuver. The two men were in a small boat helping to untie the Independence of the Seas from the end Dolphin piers:
This is an unfortunate even, but its not uncommon. Tying up and untying a ship is one of the most dangerous elements for a seafarer.
This video shows a ‘snapback.’ This occurs when a mooring line, which when put under the tremendous strain of keeping a ship alongside a pier, fails and snaps. The speed can reach over 700 feet per second! Note in the video below they are simply tying up a barge that is already at the dock and you can see at the 0:15 mark what happens when one fails.
For further demonstrations of the dangers of mooring and unmooring, hers a poorly produced and acted video from the Navy. This is actually the same video they showed me in University when I was in Seamanship class. Jump to the 3:20 mark for the snapback.