JUPITER, Fla. – The prospects of survival adrift for two 14-year-old South Florida boys were dire Thursday night.
After relatives reported Austin Stephanos and Perry Cohen missing about 5 p.m. July 24, the search-and-rescue mission expanded with the flow of the warm Atlantic Ocean's Gulf Stream. The powerful current pushes north.
The U.S. Coast Guard said the search effort Thursday was from Daytona Beach to Myrtle Beach. The private effort was ongoing from the Bahamas to Virginia Beach. Stephanos' uncle, Matt Kuntz, said they plan to continue the search even if the government gives up.
"We need more planes. We need more fuel," Kuntz said during a news conference. "We need more pilots. We can't give up."
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The boys were last seen off of the coast of Jupiter about 1.30 p.m. Their capsized 19-foot vessel turned up off of the coast of Daytona Beach on Sunday. There was still hope of survival, because a white Yeti cooler, orange life jackets, a cushion and the engine cover were missing from the boat.
Although the U.S. Coast Guard believed this was only possible for four to five days, officials said the search will continue for a seventh day Friday.
Meanwhile, the families' GoFundMe account had received $245,000 in donations in two days. The largest donation was a $20,000 anonymous post. Austin's mom, Carly Black, was selling bracelets for $150 on the "Sea La Vie Accessories" website. And a Wednesday night fundraiser raised about $40,000, a relative said.
"We really need this money badly," Kuntz said.
Andrew Register, 19, was one of the pilots who volunteered Thursday. Every five minutes he and a co-pilot switched places, so that one was navigating the plane, while the other used binoculars to look down at the vast flat ocean below in hopes of finding Austin and Perry.
"It was kind of heartbreaking not finding them," Register said. "If I was out there I would want somebody to come find me."
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Each year, Florida waters swallow a small number of boaters who venture out and never return. In 2013, when Florida had 56 boating fatalities, it also had nine missing boaters who were never found and are presumed dead, according to the state Fish and Wildlife Conservation Commission. Last year, there were 64 fatalities and six missing boaters.
Dr. Claude Piantadosi is a former Navy officer, avid boater and diver and a Duke University medical professor. He authored "The Biology of Human Survival: Life and Death in Extreme Environments." He said finding individuals outside of a boat, simply bobbing in the water, is intensely difficult.
"Single people in the ocean are the hardest to pick up," Piantadosi said.
Dr. Raj Dasgupta, a critical care doctor at the University of Southern California, said the boys' experience in the open water may be far different from what some might expect.
"They're usually not going to be found eaten by sharks like some movies would have you believe. They're going to have fatigue and muscle cramps and dehydration," he said. "It's the worst oxymoron in the world: You're surrounded by water and there's no water."
U.S. COAST GUARD PROGRESS REPORTS: Distance on the Atlantic ocean is measured on square nautical miles.
July 25 a.m. report: 5,300
July 25 p.m. report: 6,200
July 26 a.m. report: 14,447
July 26 p.m. report: 25,000
July 27 a.m. report: 26,000
July 27 p.m. report: 28,127
July 28 p.m. report: 30,992
July 29 p.m. report: 39,429
July 30 p.m. report: 43,967
There was still hope on social media. Celebrities like actor Billy Unger, actress Bailee Madison and country singer Alan Jackson took notice. On Twitter, a possible sighting on buoy cam was the most possible share, but the U.S. Coast Guard said it was not able to correlate it to the search Thursday night.
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Some said they were using live scanners and live trackers that are available on sites such as Broadcastify, FlightRadar24 and FlightAware. Thousands worldwide were listening to the Jacksonville Beach Marine scanner daily this week.
There was a hopeful story making the rounds on social media. A vigil that took part from coast to coast Thursday night was organized online. From Maine to Pompano Beach, candles were lit to guide the teens home. Many said they remained hopeful during the vigil.
In 2005, two South Carolina teens were swept out to sea on their small sailboat during a storm. After searching for them for several days, the U.S. Coast Guard and state officials began referring to their effort as a recovery operation not a rescue. Yet the teens were found alive after almost a week at sea.
A key difference from the Jupiter teens, though: They were still aboard their boat.
Follow Local10.com reporter Andrew Perez on Twitter @PerezLocal10
Map: Austin and Perry go missing
The Associated Press, ABC News and CNN contributed to this report.