Newsday reports firefighters responded to the fire behind the Freeport home around 5:25 p.m. Saturday. The fire was contained within half an hour.
The 32-foot (9.75-meter) boat was destroyed in the blaze. No injuries were reported.
Freeport Fire Department executive director Ray Maguire says it appears the fire started on top of the flying bridge. The boat belonged to the homeowner.
The county fire marshal's office is investigating.