The calls were made as strong wind and driving rain swept into South Carolina on Thursday night. Helicopters searched Thursday and Friday but found no boat or debris on the beach or in the water, the Coast Guard said.
"Coast Guard crews last night risked their lives to go out," Petty Officer 1st Class Donnie Brzuska. "It's a very serious crime."
Capt. John Cameron, a Coast Guard commander, said search conditions were perfect Friday and a hoax was suspected because nothing had turned up. He said buoys indicated that anything in the ocean should have washed ashore.
"Our search has been comprehensive," Capt. Cameron said.