Drinking locally made alcohol is common in Nigeria, Africa's most populous country, especially in rural areas where it is more affordable and poorly regulated.
Details on attacks by armed groups in rural areas are often hard to confirm, and federal government and military authorities have yet to comment on the assault.
The boat was carrying more than 80 people, most of whom were heading to farms for work in Gorau town in the Goronyo local government area of the state, officials said.
The attack occurred late Sunday night in the Naridon village in Kaduna state's Kaura council area, said Derek Christopher, chairman of a civil society group.
