Experts said Wednesday that the prospects of survival were slim for almost 300 passengers missing for more than 12 hours after their ferry sank in cold ocean waters off South Korea.
The high number of people unaccounted for — likely trapped in the submerged ship or floating in the ocean — raised fears that the death toll could rise drastically.
Some 164 survivors were rescued from the listing “Sewol” before it fully capsized, but the vessel eventually became completely submerged except for the tip of its keel.
Many of those missing are senior high school students who were departing on a field trip. One survivor said students could have been trapped inside the vessel when water rushed in.
Satellite estimates put the temperature of the sea where the ship capsized and sank at between 50 and 60 degrees — temperatures roughly equivalent to those off the Mid-Atlantic U.S. coast.
The maximum survival time for adults in such waters would be about six hours, according to Mike Tipton, professor of human and applied physiology at Britain’s Portsmouth University and co-author of “Essentials of Sea Survival”.
The only hope for survival would be if the passengers were trapped in air locks, Tipton said, adding that prediction of survival time was “more of an art than a science.”
"If they are in the water, the probability of surviving 12 hours is very, very small. If they are in air, it is better,” he said. “In both cases, children will have a lower survival time than adults because they cool more quickly as a result of a lower body mass and higher surface area to mass ratio.”
He added: “Sadly, I suspect that many drowned.”
Dense fog caused delays to shipping at the ferry’s departure point near the capital, Seoul. Conditions in the area of the disaster were calm, with winds at less than 12 mph during the day.
Jo Rawlings, a spokeswoman for Britain’s Maritime and Coastguard Agency, said the biggest risk was posed by the onset of hypothermia.
“With wet clothes on, it is almost impossible to get dry, and that makes it difficult to prevent hypothermia even if you’re no longer in the water,” she said. “Having a life jacket makes a big difference because you’re not having to fight to stay afloat, but there comes a point — especially as you get closer to the 24-hour mark — when the chances of anyone surviving are near-zero.”
Many survivors who scrambled clear of the stricken ferry were wearing orange life jackets, but it was not clear if everyone on board had time to put one on.
Passenger Kim Seong-mok said the ferry operator made an announcement asking that passengers wait and not move from their places, and that he did not hear any announcement telling passengers to escape.
“In sea water that cold, most people would succumb to hypothermia,” said Weather Channel meteorologist Bill Karins. “No one can last long in water that cold.”