It happened just before 3:00 p.m. Friday at the Hidden Mill Marine Center in the 100 block of Thompson Lane in Egg Harbor Township.
State Police say 51-year-old Gary Theno of Hammonton was working on his 30-foot cruiser when the vessel exploded and caught fire.
His body was discovered in the water shortly before 6:00 p.m.
No one else was onboard.
The marina was closed at the time of the explosion.
