NAIROBI, Kenya — A day after the Tanzanian authorities said they were unlikely to locate any more survivors from a ferry that capsized in Lake Victoria, an engineer who worked aboard the vessel was discovered alive in an apparent air pocket inside the overturned boat, the authorities said on Saturday.

Divers rescued the engineer from the ferry, the MV Nyerere, on Saturday morning, nearly two full days after the vessel overturned, the country’s minister for communication, transport and infrastructure, Isack Kamwewle, said on the state-run Tanzania Broadcasting Corporation.

By Saturday afternoon, the authorities said the death toll had climbed to 209 people, according to the broadcaster. The precise number of passengers on board has been difficult to pin down. Although the ferry had an official capacity of only 100 people, it may have been carrying three times that number of passengers when it overturned, according to some estimates.