Some survived by clinging on to wreckage while others swam at least six hours to the nearest island, authorities say.

All 18 passengers and crew on a boat that capsized off Indonesia’s Mentawai Islands have been found alive, according to authorities, with some surviving by clinging to pieces of the boat and others swimming for six hours to the nearest shore.

The survivors were transported on Tuesday to the town of Tuapejat, a town in the Mentawai Islands in West Sumatra province, where their families had been waiting for news.

The boat, carrying mostly local administration officials, capsized in bad weather on Monday morning while on its regular two-hour journey from the town of Sikakap in the Mentawai Islands to Tuapejat.

Ten passengers, including three children and a local parliament member, clung to the wreckage and were found on Guluk Guluk beach, while the other was found near the village of Matobe, according to the Mentawai Islands district chief, Rinto Wardana.

Seven, including the two crew members, had managed to reach the Mapinang fishing hamlet after swimming for hours in the choppy waters to seek help, Wardana said, adding they survived thanks to their ability to swim.

A rescue ship and an inflatable boat had been deployed for the search, with the assistance of local fishermen and residents, said Rudi, the local search and rescue agency chief who goes by a single name.

Big waves hit the boat before it capsized, Rudi added, citing testimony from one of the boat operators.

“From what we heard from the operator, it [the boat was struck from the side and then flipped over,” he said.

One of those rescued was receiving treatment at a local clinic but was in good health, he added.

Videos released by the National Search and Rescue Agency showed the operation taking place overnight in rough seas as rain fell.

Wardana, the Mentawai Islands district chief, praised the quick response of the joint search and rescue team and community, promising to conduct a comprehensive evaluation of shipping safety procedures, especially during extreme weather seasons.

He also urged boat operators to always pay attention to weather forecast information.

Indonesia is an archipelago of more than 17,000 islands, where ferries are a common method of travel. Accidents occur regularly, with weak safety enforcement often blamed.

On July 3, a ferry carrying 65 people sank off the popular resort island of Bali, killing at least 18 people. Some 17 were missing.

The search operation, which involved more than 1,000 rescuers, three navy ships, 15 boats, a helicopter and divers, officially closed on Monday.

In March, too, another boat carrying 16 people capsized in rough waters off Bali, killing an Australian woman and injuring at least one other person.

And in 2018, more than 150 people drowned when a ferry sank in one of the world’s deepest volcanic lakes on Sumatra island.