A couple and their dog were rescued from a burning boat off Crystal Cove Wednesday afternoon, according to the Orange County Sheriff's Department Harbor Patrol.

The fire broke out at about 3:30 p.m. and eventually engulfed the boat, sending a plume of smoke into the air, according to Sgt. Fritz Von Rettberg.

A civilian vessel passing by picked up the two boaters and the dog, and the Harbor Patrol sent three fire boats to put out the flames, Von Rettberg said.

The boat, however, was a "total loss," according to a tweet from the sheriff's department.

Von Rettberg said the 24-foot powerboat ended up sinking in 600 to 700 feet of water off the coast.

No one was injured, authorities said.

Von Rettberg did not immediately know what started the fire or where the boat or its passengers were from.

— Jeremiah Dobruck

Twitter: @jeremiahdobruck