The ordeal has left the seriously ill woman hospitalized for more than three weeks.
Janet Richardson, who was wearing a life jacket, spent four minutes treading water. The sea was just a few degrees above freezing at the time.
Norwegian coast guard officers let her stretcher slip into the sea as they were evacuating her from a Scandinavian cruise ship, rescue officials and her husband George told The Associated Press.
Richardson spent a week in intensive care and remains hospitalized in England, her husband said.
Norwegian police said they have launched an investigation into the accident and Norwegian Sea Rescue spokesman Ernst Larsen said the coast guard was also conducting a probe.
The Associated Press contributed to this story