The survivors alleged that they had asked driver for life jackets for everyone on board, but he had only supplied them with 15 life jackets saying that they would not need them while travelling in a modern boat.
Those who had life jackets on were able to escape with some help from local fishermen.
The boat, owned by a private agency, overturned as it approached the ferry point around 5.45pm.
An official said, the boat was making a trip from Punnami Ghat, Bhavanipuram, to Pavitra Sangamam, Ferry village. Sixteen people have drowned in the incident.
According to local media reports, there were an estimated 30 to 40 tourists on board at the time of the incident, and nearly all of them were members of the Ongole Walkers Club.
Chinnarajappa said 32 members of the Ongole Walkers' Club were among those on board. Several teams of National Disaster Relief Force (NDRF) were rushed to the spot to rescue people.
Later, 16 bodies were fished out of the river.
Alerted government immediately pressed disaster management forces in to service to rescue people struck in the water. Search and rescue operation going on.
Chief Minister N Chandrababu Naidu expressed his grief over the incident, and asked the District Collector and police authorities to take the necessary action.
Pradesh Congress Committee president N Raghuveera Reddy visited the accident spot and later the hospital.