An overloaded passenger boat capsized off Indonesia’s Sulawesi island, killing 15 people, rescuers said on Monday. Authorities said that the 33 other passengers survived.  The vessel was traveling from Lanto village in Buton Central regency in Southeast Sulawesi province to nearby Lagili village when it capsized just after midnight on Monday, local search and rescue agency head Muhammad Arafah said.The wooden boat was designed to carry 20 people.A search and rescue team initially found 15 bodies and rescued six people, and had continued their search for the others. But the operation was later called off when officials determined that all on board had been accounted for.

“There were 27 people who survived, but had not previously been reported, because they went straight home,” local search and rescue agency head Muhammad Arafah said in a statement. Three inflatable boats, two fishing boats and six divers were deployed while the search was underway.

Thousands of residents had traveled to their villages to celebrate the regency’s ninth anniversary on Sunday, and many people were transported by fishing or passenger boats. Television news showed footage of people on fishing boats retrieving bodies in the overnight darkness, and grieving relatives waiting for information at a port and a local hospital. Indonesia is an archipelago with more than 17,000 islands, and ferries and boats are a common form of transportation. With lax safety standards and problems with overcrowding, accidents occur frequently.

In 2018, an overcrowded ferry with about 200 people on board sank in a lake in North Sumatra province, killing 167 people.

In one of the country’s worst recorded disasters, an overcrowded passenger ship sank in February 1999 with 332 people aboard. Only 20 people survived.