JAKARTA ~ Navy and research ships scanned the seabed this week for a ferry that sank north of Java island 11 days ago with scores of victims thought to have been trapped, navy officers said.

“We have now several ships in the area, scanning the seabed with sonars to try to locate the ferry,” the head of the naval base in Semarang, Central Java, Colonel Yan Simamora, said on Wednesday.

He said two navy ships and a vessel from the Research and Technology Agency were combing the Mandalika area of the Java Sea to try to pinpoint the location of the ferry that sank there in rough seas late on December 29.

Only 12 bodies in various stages of decay were found Wednesday, MetroTV said. Television pictures showed the corpses being brought ashore in body bags.

The Senopati Nusantara (Archipelago Commander), carrying around 600 people, was en route from Kumai on Borneo island to Semarang when it sank in a storm.

Some 250 survivors of the disaster have been rescued so far, plucked from the seas, off life rafts and from oil rigs and islands in the Java Sea, some as recently as Sunday.

The exact location of the wreck of the ferry remains unknown.

Eastern Fleet spokesman Toni Syaiful said that the many passengers were believed to have been trapped inside the ship when it sank.

“Divers are involved in the search along a 9.6 kilometer coastline,” Syaiful said.

Once located, the divers would try to break into the wreck and evacuate “those bodies still trapped inside, especially those that could still be identified,” Syaiful said.

Survivors have spoken of panic as the ship sank in minutes and said many people were trapped as it went down.

Preliminary investigations show bad weather conditions were to blame for the accident, transport safety officials have said.

The vessel was carrying 542 passengers and 57 crew. It was licensed to carry 850.