Everyone who had been on board a stranded cruise ship, including many Americans, was safe Monday morning after a terrifying voyage off the coast of Norway. The Viking Sky was carrying just over 1,300 passengers and crew when it sent a distress signal on Saturday.

The vessel had lost power and started drifting toward land while rocking violently. The heavily-listing ship became stranded in a notoriously rough stretch of water in the Norwegian Sea. On Monday, Norway's government announced an investigation into why the ship had left port in the first place despite storm warnings.

"The high risk which the ship, its passengers and crew were exposed to made us decide to investigate the incident," Dag S. Liseth, who heads the Norwegian Accident Investigations Board, said on Monday.

As CBS News correspondent Roxana Saberi reported, video from inside the Viking Sky showed passengers dodging furniture as it flew across the floor and panels falling from the ceiling on Saturday. Outside, heavy winds and 26-foot waves whipped the luxury cruise ship that lost power for reasons remained unclear two days later.

As the ship see-sawed, a passenger filmed the icy waters gushing across the floor. Rodney Horgen of Minnesota said he was terrified.

"I thought this was it, at that time. The water is going to rush in, and this is it," he recalled of the vacation-gone-wrong.

At risk of crashing onto the nearby rocky coast of Norway, the ship dropped anchor and started to evacuate. For several hours, Norwegian rescue helicopters air-lifted more than half of the roughly 900 passengers off the stricken vessel, including Susan and Allan Dullberg, to safety.

"I am 71, he is 74 -- well, they took us up together and we got hooked in, and lifted up, that was quite a jolt," Susan said.

As the seas calmed on Sunday, the ship managed to restart three of its four engines, but tug-boats still towed the Viking Sky back to port.

Hospitals in Norway said nine people from the cruise remained hospitalized on Monday, including one in critical condition. The Red Cross said many others had been left traumatized.