Posted: 12:58 p.m. | Updated: 6:04 p.m.

A man who was operating a crane on a Smith Mountain Lake dock this morning drowned when the crane slipped off its base and tumbled almost 70 feet into the water.

Roger Dale Goad, 55, of Henry, was found in the water about two hours after the crane fell about 11:30 a.m. in the Blackwater arm of the lake, according to Franklin County's Department of Public Safety.

"It's still under investigation, but somehow the crane came loose from the barge and sank into the lake," said department Capt. Patrick Meeks.

Goad was employed by Moneta-based Plyler Homes and Docks, which was contracted to dismantle a private dock near a lake house off River Creek Road, authorities said.

He was using the crane to dismantle the steel piles that anchored the dock. The crane weighed between 18,000 and 20,000 lbs., and stood on a barge that supported it above the water, authorities said.

Divers later found Goad's body near the crane, said Al Busch, captain of the Smith Mountain Lake Marine Volunteer Fire Rescue department.

After an investigation of the incident, Meeks said, Plyler Homes would use another crane to drag the first one out of the lake.