Rescuers were searching Thursday for 38 people missing in rough seas overnight after a ferry sank near Indonesia’s resort island of Bali. Another four people died and 23 have been rescued, according to the Surabaya Search and Rescue Agency. The KMP Tunu Pratama Jaya sank almost half an hour after leaving East Java’s Ketapang port late Wednesday, the National Search and Rescue Agency said in a statement. It was bound for Bali’s Gilimanuk port, a 50-kilometer (30-mile) trip.

The ferry carried 53 passengers, 12 crew members and 22 vehicles, including 14 trucks, it said. Many of those rescued were initially unconscious after drifting in choppy waters for hours, said Banyuwangi police chief Rama Samtama Putra.

Nine boats, including two tug boats and two inflatable boats, have been searching for the missing people, battling waves up to 2 meters (6.5 feet) high in the overnight darkness.

Ferry tragedies are common in Indonesia, an archipelago of more than 17,000 islands, where ferries are often used as transport and safety regulations can lapse.