Riko said the vessel was crowded with tourists. It was also transporting dozens of motorbikes.
“When we were about a kilometer from our destination, the wind suddenly started blowing very hard, followed by big waves," he was quoted by kompas.com as saying while being treated at Simarmata public health clinic in Samosir.
"The vessel tilted to the right before it overturned due to the weight of the motorcycles," Riko said, adding that many passengers panicked and jumped into the water.
“We floated in the water for an hour before we were rescued."
As of Wednesday afternoon, a search and rescue team rescued 20 people and retrieved two bodies. The team is still looking for at least 165 others who are reportedly still missing.
Meanwhile, Agence France Presse reported that nearly 180 passengers are missing after a ferry sank into the depths of a volcanic lake in Indonesia, police said Wednesday, almost tripling initial estimates -- but the search-and-rescue agency cautioned it was still unclear how many people were aboard the vessel when it capsized.
The wooden boat, which sank Monday on Sumatra's Lake Toba, a popular tourist destination, was thought to be operating illegally, with no manifest or passenger tickets.
The situation has sparked confusion -- and different estimates from various agencies -- about the number of people on board.