Authorities say the fire started at around 8:15 p.m. at a marina near Dave and Buster's Restaurant on North Delaware Avenue just north of the Ben Franklin Bridge.
The boat broke away from the dock and floated towards the middle of the marina engulfed in flames.
Rescue boats including Westville Fire Department Fire Boat 7 of Gloucester County, New Jersey soon arrived on scene. Crews sprayed water to extinguish the blaze.
No injuries were reported.