Angry family members of missing passengers onboard the capsized Sewol ferry surround and tug at the shirt of a South Korean coast guard official (C, in blue) and a government official (2nd R) as they demand for faster and more efficient rescue work at a port where many family members are waiting for news from the search and rescue team in Jindo April 24, 2014. [Photo/Agencies]

It was unclear why the earlier maximum tonnage noted in the register document was lower than that provided by either Chonghaejin or the previous owner.

Officials with South Korea's maritime ministry and coast guard each said they were not even aware of the Sewol's cargo capacity, saying it was the shipping association's job to oversee it. The shipping association is private and is partly funded by the industry it regulates.

Even the report by the inspector reflects "a problem in the system," said Lee Gwee Bok, president of Incheon Port Development Association and a former captain. He said the Sewol never should have been cleared for operation because the register should have known the shipowner would never meet the conditions.

"The ship's operator aims to make money and instinctively tries to add more freight," Lee said.

More than 80 percent of the dead and missing were juniors at Danwon High School in Anwan, south of Seoul, where seniors Thursday returned to a campus strewn with yellow ribbons, chrysanthemums and photos of lost classmates and teachers.

Younger grades, including the 13 juniors who did not go on the ferry, will return to school next week. It's not clear when the 75 students who survived will return; most remain hospitalized, many for mental stress.

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