Coast Guard says yacht blast call may be hoax NEW YORK (Reuters) - The Coast Guard has found no debris or survivors from a reported explosion aboard a yacht 17.5 miles off the New Jersey coast, raising the possibility that the incident could have been a hoax, a spokesman said on Monday. Several Coast Guard helicopters and rescue boats have been combing the Atlantic Ocean and have yet to find debris, life rafts or individuals, Petty Officer Erik Swanson said. Asked if the Coast Guard thought that the radio call it received Monday afternoon might have been a hoax, Swanson said: "That is being considered." The Coast Guard received the transmission at about 4:20 p.m. (2020 GMT) and declared a mass casualty event after being told by the caller that an explosion aboard a yacht forced all 21 people on board to abandon ship, with seven of them injured, Chief Warrant Officer Brandon Brewer said. Swanson said the distress caller claimed to be transmitting from a solar-powered radio because the boat's radio had been destroyed. That meant the Coast Guard was unable to pinpoint the location using global positioning system tracking technology, Swanson said. The Coast Guard received just the one transmission and nothing since, Swanson said. The search, however, has not been called off yet. "We're going to continue the search for a while now," Swanson said. As of 8:15 p.m. one Coast Guard helicopter remained in the air and several boats at sea as part of the search, Petty Officer Thomas McKenzie said. Brewer said the yacht was called Blind Date. Reporting by Daniel Trotta and Dan Burns; Editing by Sandra Maler and David Brunnstrom