Updated 4:20 p.m. June 19, 2014.

Flames engulfed a dry-docked 110-foot yacht at a South Bay boatyard Thursday, sending intense flames and thick smoke over San Diego Bay, authorities reported.

The blaze at Marine Group Boat Works in 900 block of G Street in Chula Vista erupted about 9 a.m., according to fire officials. The motor vessel, valued at $17 million, was expected to be a total loss.

Authorities evacuated the boatyard as a precaution. Two people were treated for smoke inhalation, officials said.

Due to the intensity of the flames, which began on a lower deck of the private vessel, crews had to fight them from shore, spraying retardant foam and water from ladder hoses, Chula Vista Deputy Fire Chief Jim Garcia said.

Firefighters were still working on hot spots by late afternoon, after it took six hours to put out the flames, Garcia said. It appeared they confined the damage to the yacht, he added.

The yacht was in the dry dock for repairs, according to Garcia.

The cause of the fire was not immediately clear.

— City News Service