In addition the 18 survivors, three bodies have also been recovered, bringing the total estimated number aboard the 60-person capacity ferry to 213.
Recovery efforts have been complicated by the lack of an official passenger manifest.
Without any way of knowing the exact numbers aboard the stricken boat, the Indonesian authorities are relying on estimates provided by family members who arrived following news of the accident.
Nurhayati, who only goes by one name, rushed to Tigaras Port, the boat's intended destination, in hope of hearing news of her brother, 30-year-old Yudi, who was visiting for the Eid holiday from his home in Pekanbaru, in Riau Province.
He was traveling with his wife and two-year old son, and posted a picture on Facebook of his family boarding the ferry at 11 a.m. on Monday, with plans to come back later that day. His phone is now inactive.
"None of them know how to swim," said Nurhayati, wiping away tears at the makeshift crisis center set up by authorities.
Another family member desperately looking for answers was Suparmi, who also only uses one name, and who arrived at the center at 10 a.m. on Tuesday in search of her 23-year-old son, Muhammad Apriani Sutomo.
He was with his girlfriend and told his mother he planned to visit the lake as part of a day trip.
Suparmi has been ringing his phone ever since he failed to come home, and his girlfriend's family has been unable to reach her.
"Please don't let it be my child. He said all he wanted to do was spend the day swimming," she said, before covering her face with her hands.

Despite the slow progress, both Nurhayati and Suparmi are reluctant to criticize the search and rescue effort, which has also been hampered by high winds and poor visibility.
For both of them, the agonizing wait for news of their loved ones continues, and Nurhayati urges the search and rescue teams not to give up.
Although she believes her brother, his wife and her nephew have all drowned, she continues to hold out hope they will be found.
"I don't care if I just get their bodies back," she said, "I can't rest not knowing where they are."
Human error involved
The exact cause of the accident is unknown, with authorities pointing to both bad weather and overloading as potential factors.
However, Chief of Police for Simalungun Regency, Liberty Pandjaitan, told CNN that investigators believe "human error" was also involved.

"The boat captain was found alive and has been taken into custody," said Pandjaitan, who said police would not release details of the case publicly for fears of reprisals against his family.
Lake Toba is a popular sightseeing choice in North Sumatra thanks to its status as the largest crater lake in the world which spans some 1,130 square kilometres (440 square miles).
The Indonesian government recently declared the area one of the "
10 New Balis," a new tourism growth strategy -- and the brainchild of Indonesian president, Joko "Jokowi" Widodo -- designed to lure foreign visitors to other parts of the country.
The strategy also included the opening of Silangit International Airport, an hour's drive from Lake Toba, in October 2017.
Despite a concerted effort to encourage more foreign visitors to Lake Toba, officials have been unable to confirm if any foreign nationals had been on board the ferry.