Perhaps it was inevitable: Minutes after Diana Nyad, the 64-year-old marathon swimmer, landed on the sandy shores of Key West, Fla., succeeding in her fifth attempt to swim the straits from Cuba, fellow swimmers unleashed a barrage of censure and doubt.
Swimmers asked, Was she truly unaided during all those hours in the open sea, with only her crew observing? Based on her GPS data released by her team, how did she manage to swim nearly 53 hours, crossing 110 miles, considering that her average speed was 1.7 mph at the start and end of the swim? And were her two handpicked independent observers truly independent?
In the week since Nyad arrived in Key West to international acclaim, apparently becoming the first person to swim the 110-plus-mile route without a shark cage, doubters have multiplied, taking to marathon swimming websites and other places online to criticize Nyad's methods and her team's transparency and to raise questions about the veracity of her claims.
Nyad said she was not surprised by the questions and criticisms.
"I'm an absolutely aboveboard person who never cheated on anything in my whole life," Nyad said. "When someone does something they've been trying to do for a long time and you know how difficult it is, it's only logical. I hope they're not questioning if I'm an honest person.
"They want to know how the facts came down so they can understand it. They have every right to ask all these questions, and we have every intention to honor the accurate information."
Her swim was not documented by independent news media, as were her previous attempts. Nyad acknowledged that the news media had wearied of the story because she had failed so often.
Nor did members of Nyad's crew take continuous video of the swim, a strange decision to some marathoners.
"If I was doing a swim that had never been done before and everyone thought impossible, I'd have a video camera on me continuously," said Evan Morrison, the San Francisco founder of Marathonswimmers.org, an online community of more than 700 athletes.
But Steven Munatones, a former marathon swimmer and swimming official who has served on Nyad's earlier crews, said he had no doubts.
"I am 100 percent satisfied based on the GPS data, marine information, written information and personal interviews that she did the swim," said Munatones, of Huntington Beach, Calif.
Munatones said he intended to review all the data from Nyad's crew with a panel of other swimming experts, including the president of the Catalina Channel Swimming Federation, so they can answer all the questions from the swimming community. The federation president, Forrest Nelson, said he had agreed.
The biggest source of grousing pertains to Nyad's speed and distance covered and the amount of push she got from the currents. Her previous Cuba-to-Florida attempts were undone by bad weather and uncooperative currents, which tend to sweep eastward toward the Bahamas. Nyad is a plodder; she says she averages less than 2 mph. And she was at 1.7 mph when she left from Cuba on Aug. 31 and again when she neared Key West.
One marathon swimmer, Andrew Malinak of Seattle, used Firebug, a Web development tool that collects code, to glean Nyad's GPS data from the swimmer's official website. Crunching the numbers, he surmised that Nyad was traveling at an increasingly speedy clip on the swim's second day - from 2 mph to more than 6 mph around 31 hours into the swim. After her crew made the data available with time stamps, Malinak revised his work and said that Nyad's top speed was nearly 4.5 mph for a stretch. The pace was inconsistent, he said, with huge surges and then valleys, plunging her times to 2 mph.
"The rapid increase and two subsequent rapid decreases in her speed, combined with the already fast pace, still leave me skeptical of her swim's authenticity," said Malinak, a geotechnical engineer, who has swum around Manhattan. Fellow swimmers have asked on an online forum if it is possible that Nyad was on a boat when those surges happened.
Nyad and some onboard her flotilla said no. Her navigator, John Bartlett, a custom boat builder in the Florida Keys, says the fast water flows were predicted by a Connecticut physical oceanographer. Some of the fastest currents unfolded around noon on the swim's second day, moving at 3.8 knots, close to 4 mph.
Bartlett said that currents varied, and that the team had worked Nyad sideways and northward through the currents, a technique called crabbing. "Everyone is saying, 'Wow, she was going fast, how is that possible?'" Bartlett said. "The currents were going fast."
The currents eased up to 1.4 knots on Day Three, but the direction was more northern, and thus more helpful to Nyad.
Bartlett cautioned the people crunching numbers. GPS data culled by Malinak from spot trackers, set on the deck of the escort boat, is far less reliable than the information from the professional GPS units Bartlett used. The spot trackers are "designed to be a convenience so the public can watch the progress, but they're not infallible and not precise," he said. "If there's a discrepancy between what I have on paper and the spot trackers, you can just disregard the spot trackers."
Critics say the observers -- typically people who have never met the athlete -- are unknown in the swimming community, odd for such a high-profile event. Munatones was supposed to observe the swim.
On earlier outings by Nyad, Munatones said he "did everything including get sponsors, organize the crew, blog, and jump in the water and help feed her." But when the team decided that the conditions were perfect, Munatones was on a plane to Tokyo. Nyad said she had to scramble to find two substitutes, both Key West locals who do not have a history of either swimming or observing record crossings.
One, Janet Hinkle, a licensed Key West boat captain, said she got the call at the last minute. She said she had met Nyad in 2011, providing her with a home to live in before a swim. Hinkle had never observed any swim, but she said she got tips from Munatones and said she was unbiased.
"I believe she asked me because I would be an objective observer," Hinkle said. She said she never observed Nyad getting on board the boat during the swim or being pulled by a craft.
Nyad's fans have called the critics "haters" who are jealous.