Firefighters extinguished a boat fire today that destroyed a powerboat and sent up a dramatic plume of black smoke in Kaneohe Bay.

The fire started about noon at the sand bar aboard a roughly 30-foot boat, said Deborah Ward, Department of Land and Natural Resources spokeswoman.

She said the boat, called Serenity Now, was destroyed.

Honolulu Fire Capt. Michael Jones said the owner was the only person onboard when the fire broke out. The man abandoned the vessel and was safely picked up by Waterfront Operations from Marine Corps Base Hawaii in Kaneohe, he said.

Initial reports gave conflicting accounts of how many people were aboard, and firefighters confirmed with the owner that he was the only one who was on the boat, Jones said.

Firefighters extinguished the blaze by dumping water on the flames with a helicopter, he said. The cause was under investigation.

Kahaluu resident Walter Wright said he was driving home when he saw a “big towering plume of black smoke.”

He said the boat drifted about 400 yards as it burned and ended up on the inside of a reef about 3oo yards offshore of Lihikai Drive.

He overheard state officials say a salvage company would have to remove the fiberglass boat because it was too heavily damaged to be towed from the reef.

“That boat melted like a marshmallow over a bonfire,” Wright said.

Ward said the boat’s owner, a Kailua resident, is responsible for the boat’s removal.