Dozens of survivors adrift at sea were picked up by fishing boats Tuesday, four days after a ferry sunk in a storm off central Indonesia, an official said. Efforts to locate others continued.

With about 400 people still missing, strong winds and poor visibility prevented search aircraft from taking to the skies, but ships patrolled the waters off the Java coast in the area where the boat went down before midnight Friday.

About 200 survivors have been found so far. Officials say the search will continue until Sunday. Thirteen corpses have been recovered and scores of others have been spotted floating at sea.

Survivor Susilo, 35, was picked up by fishermen and taken to hospital with chest pain and respiratory problems along with five others after drifting in a life raft for four days.

"Six among us died, one by one, due to starvation, cold and after drinking too much sea water," he said.

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Another 27 survivors were rescued elsewhere off the Java coast Tuesday and taken to the eastern port city of Surabaya.

On Tuesday, rescue teams were focused around Madura island, about 375 miles east of the capital, Jakarta, said rescue worker Agus Anwari. "Heavy surf and high waves are still hampering our relief efforts, but we believe many survivors are over there, they need our help," he said.

In another sea incident, officials said a speed boat capsized in poor weather Monday night off the coast of Borneo island, killing 15.

It was the fourth deadly accident in less than a week in the vast archipelago. Besides the ferry sinking, scores died last week in flooding and mudslides triggered by heavy rains, while a plane crash on Monday killed at least 90 people.

Relatives of those aboard the ferry camped out at a local hospital and were becoming increasingly desperate for news. A temporary morgue was being set up at a port close to where the crowded passenger ship sunk. Hundreds of body bags have been readied.

The Senopati Nusantara sank quickly after being pounded by heavy waves for more than 10 hours as it neared the end of a two-day journey from the Indonesian section of Borneo island to the country's main island of Java.

The ferry, which was built in Japan in 1992, had a capacity of 850 people. Officials say bad weather was the cause of the accident.