An Action News viewer captured cell phone video of the boat, fully engulfed in flames, around 11:30 Tuesday night.
The boat was docked at the Seaview Marina on the 300 block of Longport Boulevard in Egg Harbor Township.
Fire companies were called from around the area to fight the flames. Firefighters had trouble getting their hoses to the yacht because it was at the far end of the dock.
New Jersey State Police say this fire is suspicious. The police arson unit is investigating.