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Time is Short for High-Risk Rescue Effort Time Is Short for High-Risk Rescue Effort
(35 minutes later)
With rising waves and swift currents off the southern coast of South Korea having largely stymied search operations around a capsized ferry late Thursday night, the fate of 271 people still missing was unknown. It was unclear even how many might still be aboard the vessel — which was underwater save for a small section of its keel — and if so whether any were in areas with pockets of air.With rising waves and swift currents off the southern coast of South Korea having largely stymied search operations around a capsized ferry late Thursday night, the fate of 271 people still missing was unknown. It was unclear even how many might still be aboard the vessel — which was underwater save for a small section of its keel — and if so whether any were in areas with pockets of air.
Experts said that if there were air pockets, survival would depend in part on their size and the number of people in them.Experts said that if there were air pockets, survival would depend in part on their size and the number of people in them.
Eric Hexdall, clinical director of Duke Dive Medicine in Durham, N.C., and a former United States Navy salvage diver, said the limiting factor in such confined areas would probably not be the oxygen in the air, but the carbon dioxide from exhalation, which is toxic at high concentrations. “You’d build up carbon dioxide way before you ran out of O2,” Mr. Hexdall said.Eric Hexdall, clinical director of Duke Dive Medicine in Durham, N.C., and a former United States Navy salvage diver, said the limiting factor in such confined areas would probably not be the oxygen in the air, but the carbon dioxide from exhalation, which is toxic at high concentrations. “You’d build up carbon dioxide way before you ran out of O2,” Mr. Hexdall said.
Rescue officials had announced plans to pump air into the ship, but the attempt was delayed. Even if that provided passengers with more air to breathe, however, hypothermia from exposure to cold water could prove fatal, said Dr. Alan M. Steinman, director of health and safety at the United States Coast Guard and an expert on water survival.Rescue officials had announced plans to pump air into the ship, but the attempt was delayed. Even if that provided passengers with more air to breathe, however, hypothermia from exposure to cold water could prove fatal, said Dr. Alan M. Steinman, director of health and safety at the United States Coast Guard and an expert on water survival.
The ferry, which carried about 475 people, two-thirds of whom were high school students, capsized on Wednesday morning, and water temperatures in the area were reported in the low 50s. There is no rule of thumb as to how long a person can survive in such temperatures, Dr. Steinman said. “It’s a complex issue,” he said. “But it’s not good.”The ferry, which carried about 475 people, two-thirds of whom were high school students, capsized on Wednesday morning, and water temperatures in the area were reported in the low 50s. There is no rule of thumb as to how long a person can survive in such temperatures, Dr. Steinman said. “It’s a complex issue,” he said. “But it’s not good.”
Flotation vests, which appear to have been put on by most if not all of those on board during the accident, would help in survival, Dr. Steinman said. By not having to swim to stay afloat, passengers would pump less warm blood to their extremities and lose heat less rapidly.Flotation vests, which appear to have been put on by most if not all of those on board during the accident, would help in survival, Dr. Steinman said. By not having to swim to stay afloat, passengers would pump less warm blood to their extremities and lose heat less rapidly.
But smaller and younger people lose heat faster than larger people and adults, Dr. Steinman said, because they have proportionally more skin, and thus a higher ratio of surface area to weight.But smaller and younger people lose heat faster than larger people and adults, Dr. Steinman said, because they have proportionally more skin, and thus a higher ratio of surface area to weight.
The best situation, he said, would be to be in an air pocket that was large enough to allow someone in it to get most or all of the body out of the water. That would slow the rate of heat loss.The best situation, he said, would be to be in an air pocket that was large enough to allow someone in it to get most or all of the body out of the water. That would slow the rate of heat loss.
Dr. Steinman, who helped investigate several Coast Guard accidents in which crew members were trapped in capsized ships, said that escape was sometimes possible. He cited a 1977 accident near Cape Disappointment in Washington in which a training vessel overturned, trapping eight of the crew members in an air pocket. Six of the men escaped by swimming out through a cabin door and then up to the surface. Two men were too afraid to leave and were still inside when the ship eventually sank.Dr. Steinman, who helped investigate several Coast Guard accidents in which crew members were trapped in capsized ships, said that escape was sometimes possible. He cited a 1977 accident near Cape Disappointment in Washington in which a training vessel overturned, trapping eight of the crew members in an air pocket. Six of the men escaped by swimming out through a cabin door and then up to the surface. Two men were too afraid to leave and were still inside when the ship eventually sank.
“The biggest thing was the psychological factor,” he said.“The biggest thing was the psychological factor,” he said.
The Coast Guard vessel was also relatively small — 41 feet long — and those aboard were familiar with it. The Korean ferry, the Sewol, is much larger and the passengers had been on it for about 12 hours.The Coast Guard vessel was also relatively small — 41 feet long — and those aboard were familiar with it. The Korean ferry, the Sewol, is much larger and the passengers had been on it for about 12 hours.
By Thursday night, more than 170 vessels and about 500 divers were involved in the search at the ferry site. It was not clear whether divers had begun to search the ship itself, but diving into a dark overturned vessel carries high risks. Dr. Steinman and Mr. Hexdall noted, for instance, that the United States Navy requires that a diver be left inside each compartment along the way, to help ensure that everyone can make it back out. That adds additional complexity to a rescue attempt.By Thursday night, more than 170 vessels and about 500 divers were involved in the search at the ferry site. It was not clear whether divers had begun to search the ship itself, but diving into a dark overturned vessel carries high risks. Dr. Steinman and Mr. Hexdall noted, for instance, that the United States Navy requires that a diver be left inside each compartment along the way, to help ensure that everyone can make it back out. That adds additional complexity to a rescue attempt.