SANDY HOOK, N.J. (AP) _ A motor yacht with several people aboard exploded on Monday near a popular summer beach vacation spot and quickly sank, but no injuries were immediately confirmed, the U.S. Coast Guard said.

Twenty-one people were aboard the yacht, the Blind Date, when the blast occurred Monday afternoon about 17 nautical miles due east of Sandy Hook, in central New Jersey, authorities said. Everyone aboard apparently made it on to life rafts, according to a Coast Guard spokesman, who said there were unconfirmed media reports of at least seven injuries.

Numerous Coast Guard crews and two New York City police helicopters were dispatched to the scene. Several emergency response crews waited at Sandy Hook, a popular getaway spot for New York residents because it’s just a short ferry ride from lower Manhattan.

Coast Guard Lt. Joe Klinker said as of about two hours after the blast life rafts hadn’t been located. He said the boaters were unable to transmit a GPS position to authorities. He said rescuers knew their approximate location “but not to the point that we’re able to shoot right out there and find them,” Klinker said.

The water was cold, around 66 degrees, he said.

“The quicker we’re able to locate them the better, and the good news is we do have reports that there were life rafts,” he said.

The cause of the blast, which happened around 4 p.m., was unknown.

Sandy Hook is owned by the federal government and is mostly managed by the National Park Service. It’s a unit of the Gateway National Recreation Area.