The fire at the Holiday Hill Marina in the 3900 block of Calawasse Road was called in at 5:06 p.m., fire officials said.
Firefighters arrived to find the powerboat, a 1987 42-foot Silverton Cruiser, fully engulfed in flames. County fire spokesman Capt. Russ Davies said at 5:33 p.m. firefighters were working a fire aboard one boat, though reports and a fuzzy photo that appeared on social media suggested the fire had spread to other boats in the marina.
Nearly an hour, later firefighters were using foam to extinguish remaining fire in the bow of the boat, Davies said.
The boat was a liveaboard and the single occupant is being assisted by the American Red Cross.
Investigators were on the scene preparing to investigate the possible cause of the blaze as soon as it is extinguished. Davies said electrical connections or a heat source were two areas that would be examined.