The US Coast Guard has responded to a boat fire near Carlsbad, California, on the morning (local time) of Thursday, July 15.
Coast Guard Sector San Diego watchstanders received several reports of a 50-foot (15-metre) boat on fire approximately seven miles (11 kilometres) off the Carlsbad coast at around 09:00.
Coast guard watchstanders despatched an MH-60 Jayhawk helicopter crew and diverted the cutters Munro, Benjamin Bottoms, and Haddock.
While coast guard assets were en route, the Oceanside harbour master confirmed that the boat's name was Relentless. The harbour master said he saw the boat leave the Oceanside Harbor heading towards Carlsbad that same morning and stated that the owner lived aboard the boat and was presumed to have been alone.
The coast guard cutters arrived on scene and worked together to extinguish the boat fire while the Jayhawk helicopter crew searched for survivors.
The boat sustained significant damage and eventually sank in approximately 1,800 feet (548 metres) of water.
The Jayhawk crew conducted search patterns for more than six hours spanning over 600 square miles (1,553 square kilometres) with no sightings of survivors.
The three coast guard cutters were still searching for survivors as of 18:00 on Thursday.