Two foreigners remain missing. Those rescued on Monday were found in the early hours some 100km off the coast of Sumbawa island, which is close to Sangeang, a search official said.

“They were all found together, some in a lifeboat and some floating with their life jackets on around 100km off Sape,” on the east of Sumbawa, said rescue official Budiawan, who like many Indonesians goes by one name.

Budiawan, head of the search and rescue agency on Lombok island which lies to the west of Sumbawa, said they were now in the town of Sape.

“The search operation is continuing this morning, and involves the military and police,” he said.

The foreigners rescued on Monday were from the Netherlands, Italy and Germany, while the Indonesians were four boat crew members and a tour guide, said national disaster agency spokesman Sutopo Purwo Nugroho.

A Dutchman in the group said that they were in the water for about 40  hours, taking turns to spend time in the lifeboat – which seated seven people – and floating in the water in the life jackets.

“So we had this system, and in the beginning it was not easy ... but later on the system went on, and we changed and changed,” Jan van Ommen said from the town of Sape on Sumbawa, where the group was taken after being rescued.

He said the boat hit a coral reef after setting off from Lombok on Thursday but the crew insisted there was no problem and the voyage continued.

However on Friday night, the vessel was hit by a storm and started to take on water.

“The crew came out shouting ’very dangerous situation’,” he said, adding that they saw water leaking into the boat.

As the boat slowly sank and broke apart, some decided to swim to Sangeang.  Van Ommen and six others crammed into a life boat, while six others wearing life jackets swam alongside, he said.

“At the end of the second day they found us,” he said, speaking from a local health centre where some of the survivors were being treated.

French survivor Bertrand Homassel said on Sunday how and he and a group of others had to swim for six hours to reach Sangeang as the vessel slowly foundered, as only a small number could fit in the single lifeboat on board.

He said the boat started sinking after being hit by a storm on Friday night, which damaged the hull.

“Six people were in the lifeboat. The others climbed onto the roof of the boat, which had not completely sunk,” he said, speaking from a hotel in Bima, a city on Sumbawa where those rescued Sunday were taken.

“We waited until midday on Saturday. We were 5km from the coast – there were many big waves separating us from the coast.

“People started to panic ... Everyone took the decision to swim to the closest island, 5km away, where there was an erupting volcano.”

He said they arrived in Sangeang as the sun was setting, but found it deserted. They spent Saturday night there, surviving by drinking their own urine and eating leaves.

On Sunday, they attracted the attention of a passing boat by waving their life jackets, and were rescued and taken to Bima, he said.

“I was really very lucky,” Homassel added.

Komodo island is one of several islands that make up the Komodo National Park, a protected area.

Its eponymous lizards can grow up to three metres long and have a venomous bite.

Indonesia relies heavily on boats to connect its more than 17,000 islands, but has a poor maritime safety record.

Two vessels sank last month in different parts of the archipelago as millions travelled for the Muslim Eid ul-Fitr holiday, leaving at least 36 people dead.

Fatal incidents involving asylum-seeker vessels trying to make the treacherous sea crossing from Indonesia to Australia are also common.

But boat sinkings involving foreign tourists are rare, with accidents in Indonesia’s fast-growing aviation sector more of a danger for overseas visitors in recent years.