A Man Fell From a Cruise Ship. And Survived.

The Carnival Valor had been at sea for only a day when calls came over the loudspeaker asking a certain passenger to please report to customer service.

The man, a 28-year-old American citizen, had been reported missing by his family that morning.

It was Thanksgiving, and the Valor, a 3,756-passenger cruise ship that had left New Orleans the day before, was heading toward Cozumel, Mexico.

Crew members soon began searching passengers’ cabins, said Shant’a Miller White, who was traveling with her husband and family. One employee entered her cousin’s cabin and said, “We just need to make sure everything is OK.”

“We didn’t know what was going on,” Ms. White, 48, recalled. Then, at dinner, came another announcement: The ship needed to change course to execute a search and rescue operation.

Ms. White pictured the unknown passenger alone in the water and felt sick to her stomach.

“Did they fall to the bottom? Did the sharks get them?” Ms. White recalled thinking. She began to pray.

The passenger, according to the Coast Guard, turned out to be James Grimes, 28, who had been traveling with his parents and siblings on the five-day cruise. His family had last seen him the night before, around 11 p.m.

But by 10:45 on Thanksgiving morning, when there was no sign of him, the family notified the crew, the Coast Guard said.

At 8:10 p.m., more than nine hours after his family reported him missing, a passing tanker spotted the man near the mouth of the Mississippi River and alerted the Coast Guard.

Rescuers found Mr. Grimes struggling in the water, waving frantically and trying to keep his head above the surface.

When the crew of the MH-60 Jayhawk helicopter lifted him out, he was in shock, had mild hypothermia and was extremely dehydrated, said Lt. Seth Gross, who managed the search and rescue operation for the Coast Guard. But he was alive and in stable condition.

Mr. Grimes, whose family described him as an exceptional swimmer, had treaded in 65- to 70-degree water for hours, withstanding rain, 20-knot winds and three- to five-foot waves in the Gulf of Mexico, where bull sharks and blacktip sharks are common, Coast Guard officials said.

“This case is certainly extraordinary,” Lieutenant Gross said. “The survival instinct, the will to survive is just crazy.”

How often does this happen?

Falling from a ship into a vast sea may be a cruise passenger’s worst nightmare. While the chances of going overboard are exceedingly remote, according to statistics from…