MOKPO, South Korea (AP) -- It is a decision that has maritime experts stumped and is at odds with standard procedure: Why were the passengers of the doomed South Korean ferry told to stay in their rooms rather than climb on deck?
Evacuations can be chaotic and dangerous, and an important principle in maritime circles is that even a damaged ship may be the best lifeboat. But car ferries like the Sewol, which left about 300 people missing or dead when it sank Wednesday, are different.
Under certain conditions -- like those that confronted the Sewol -- car ferries are particularly susceptible to rapid capsizing. This makes it critically important that when there is trouble, the crew quickly evacuate passengers, or at least gather them in preparation to abandon ship.
Though experienced, the captain of the Sewol, Lee Joon-seok, delayed evacuation for at least half an hour after the ship began tipping. Passengers, most of them teenagers on holiday, were initially told to stay below deck.
"If you would have not said a word to them, they would have left to the deck to see what was going on," and a crucial step in any evacuation would have been accomplished, said Mario Vittone, a former U.S. Coast Guard maritime accident investigator and inspector. "They certainly made it worse than saying nothing at all."
Lee has worked about four decades at sea, split between ferries and ocean freighters. A representative for his employer, Chonghaejin Marine Co. Ltd., told Yonhap News Agency that he has sailed the company's route from Incheon, near Seoul, to the southern island of Jeju for eight years. A member of his crew, Oh Yong-seok, told The Associated Press that Lee worked on the ferry about 10 days per month.
After his arrest Saturday on suspicion of negligence and abandoning people in need, Lee apologized for "causing a disturbance" but defended his decision to wait.
"At the time, the current was very strong, the temperature of the ocean water was cold, and I thought that if people left the ferry without (proper) judgment, if they were not wearing a life jacket, and even if they were, they would drift away and face many other difficulties," Lee said. "The rescue boats had not arrived yet, nor were there any civilian fishing ships or other boats nearby at that time."
Vittone and Thad Allen, the former head of the U.S. Coast Guard, said that explanation misses a key point: The captain could have ordered passengers on deck, even if it was not certain that they would have to evacuate the ferry. Allen said in an email that two things needed to be done simultaneously: "Keep trying to save the ship but mitigate the risk to loss of life by preparing the passengers to abandon ship."
Vittone said in an email that while an evacuation would carry risks, there would be no risk in gathering passengers at "muster stations," designated areas the crew would identify during a safety demonstration early in the voyage. From these areas, crew members could make sure everyone had life vests on and then direct people to emergency exits.
"He could have always changed his order if the ship wasn't sinking," he said. "Worst case then would have been that he would have made his passengers suffer the inconvenience of standing around on deck for a few minutes."
While it is not yet certain just what happened with the Sewol, car ferries can tip quickly because of what is known as the "free surface effect." Water that collects on the car deck, which extends the length of the ship, can accelerate the capsizing as it sloshes around. This is not an issue with other ferries, whose decks near the water line are compartmentalized. Even a modest shift in a car ferry's cargo could tilt the ship initially, and if water enters the car deck, the free surface effect could take hold.
Once the Sewol started listing severely, life boats were submerged on one side and equally useless on the other, where gravity held them to the side of the ferry. Passengers became trapped as the ship tilted so badly that walls became ceilings.
Following a pair of European sinkings in which more than 1,000 people died -- the Herald of Free Enterprise in 1987 and the Estonia in 1994 -- the United Nations' International Maritime Organization studied car ferry design flaws as well as how best to evacuate vessels.
The changes, which included better escape routes and an evacuation analysis in the design process, applied to newly built ships. The Sewol was built in 1994, and thus was not subject to these regulations.