Officials say the 26-foot tug boat, named The Pushy, hit a 10-foot swell just after 7:30 p.m. The wave broke the dow line, sending the 125-foot barge drifting away.
The barge washed up on Silver Point County Park, just west of Atlantic Beach in Nassau County.
One person was rescued from the barge by an NYPD helicopter.
A second tug, the Susan Miller, responded to help the tug operator.
The barge was being moved from the Robert Moses Inlet Bridge, where a construction company called Caribe Construction was sandblasting and painting the bridge.
The barge was carrying work materials, such as generators, and was en route to the Weeks Marine Ship Yard.