The Coast Guard's search for a boater who claimed his vessel was sinking off Cape Canaveral has become a $178,000, taxpayer-funded mystery. 

Authorities say that's how much it cost to search a combined 2,166 square miles using everything from Coast Guard cutters and a HC-130J long-range surveillance aircraft to an HH-60 rescue helicopter while scouring the seas for survivors in the reported incident.

"It can be very expensive, especially when it can be determined as a hoax case. With this call, there still may be another explanation. The call came from an offshore area east of Cape Canaveral," Lt. Cmdr. Matthew Moorlag of the Coast Guard said.

"It's also dangerous to our crews and other maritime vessels. It can keep us from conducting other important duties."

The incident began at 4:30 p.m. Sunday after Coast Guard crews received a distress call over the airwaves on a VHF channel used for maritime communications.

"Mayday, mayday. . . . Vessel going down. . . . We're going down quick," an unidentified man said during the distress call

The Coast Guard immediately dispatched an HH-60 rescue helicopter -- which operates at $6,530 an hour in fuel and staffing costs -- from its Clearwater station.

A 45-foot rescue boat immediately left from U.S. Coast Guard Station Port Canaveral.

By nightfall, the Coast Guard called in two HC-130J long-range surveillance aircraft -- the most expensive, costing $7,648 an hour to operate -- from its Elizabeth City, N.C., air station to help search the ocean.

No debris or survivors were found, and officials said there were no reports of missing boats or persons connected to the area.

At least one boat was found in the area where the distress call originated, but the Coast Guard determined it was not related.

"We respond to all mayday calls. We treat all of them as legitimate. The vast majority of these calls are real," Moorlag said, adding that the Coast Guard can track calls to a general area. The search was suspended by 8 a.m. Tuesday with investigators stopping short of saying the distress call was a hoax.

"Although no additional information was received from any source indicating a vessel was in actual distress, the Coast Guard doesn't have an indication that this was a deliberate hoax call," Capt. Drew Pearson, Seventh Coast Guard District chief of incident management, released in a statement.  

Anyone caught making a hoax call to the U.S. Coast Guard could face up to six years in federal prison along with a $250,900 fine and another $5,000 in civil fines.

In 2006, Coast Guard crews tracked down a caller off Boynton Beach, who claimed his vessel was taking on water with five children and five adults aboard.

Crews verified the call as a hoax. The man, identified as Robert Moran, was sentenced to 30 months in federal prison and ordered to pay $347,000 in fines.

Later in September 2006, another hoax call made over the VHF radio waves resulted in the Coast Guard searching the area off Ponce Inlet. The caller was later sentenced to 366 days in prison and fined $60,000.

"If we're able to determine that it was deliberate, charges will be filed," Moorlag said.

"But until we can prove otherwise, we treat every call as legitimate."