The group left the village of Piermont for a short trip aboard the 21-foot Stingray across the river to Tarrytown, about 30 miles north of New York City, authorities said.
The boat struck a barge carrying materials for the construction of a replacement for the Tappan Zee Bridge, authorities said. Chief Barbera said the barge was equipped with lights, but it was still difficult to see on the water late at night.
Miss Stewart, of Piermont, worked for an insurance company. She and Mr. Bond were to be married at the Good Shepherd Lutheran Church in Pearl River, with a reception at a vineyard in Hillburn, her stepfather, Walter Kosik, said.
The couple had known each other for years and used to go to church together, he said.
“They have been friends the whole time, and they fell in love about 3½ years ago,” Mr. Kosik said.
The New York State Thruway Authority, which is overseeing the bridge project, said it was reviewing safety procedures. It said the lighting on the barges appeared to be functioning normally.
“Our thoughts and prayers are with the victims and their families during this difficult time,” the authority said in a statement.