The fire was burning on a yacht docked at Cracker Boy Boat Works next to the city marina.
It spread to other boats downwind and a tent at the boat yard.
The yacht is called "Sea Alice" and is registered out of Vancouver.
A spokesman for the Port of Palm Beach told WPTV that the fire is preventing a cruise ship from docking.
The cause of the fire was not immediately known.
No injuries have been reported.