HAVANA - American endurance swimmer Diana Nyad began her second attempt in as many months to traverse the 103 miles of sea between Cuba and Florida, waving goodbye to well-wishers before jumping feet first into the still water at a Havana marina, then stroking toward the horizon.
The 62-year-old Los Angeles woman hoped to break her own world record for open-water swimming without a shark cage that she set in 1979 when she stroked from the Bahamas to Florida.
Her last attempt at the Cuba-to-Florida crossing failed Aug. 9 due to a crippling asthma attack that forced her gasping from the water after 29 hours.
Nyad insisted that this time around she was ready to brave the choppy seas, schools of jellyfish and limits of human exhaustion to accomplish her lifelong dream.
As darkness fell, about an hour and a half into the swim, Nyad's team sent a Twitter message that she was "going strong."
A later message relayed news of a first, stinging setback.
"Diana has been stung by what we believe is a moon jelly. She is trying to clear herself of tentacles and continue the swim," it read.
Just before she set off from Hemingway Marina on Friday evening, assistants smeared grease on her shoulders to prevent chafing during the planned 60-hour journey. She pumped her fists in the air as her support team blew horns and cheered from waiting boats.
"I feel good. I feel very good," Nyad said. "But as you know, it really doesn't matter how I feel right now."
She acknowledged being a little more subdued than the last time she departed from this same marina.
"Not that I was ever cocky, but having been through this now and been so deeply, emotionally disappointed, I don't want to take anything for granted," Nyad said.
"It's not that I don't want to enjoy every moment and savor it, but it doesn't do any good to act like, 'Hey I've got this in the bag, this is going to be easy."'
Before jumping in, Nyad weighed herself, tipping the scales at 146 pounds. She said she expected to lose about 15 pounds over the course of the journey. Her schedule called for to reach Florida early Monday morning.
She hoped to take advantage of what she called a "magical window" of calm seas and favorable weather forecast to last through the weekend.
Last month after her previous attempt failed, Nyad had vowed there would be no repeat, but she joked earlier Friday that nobody should have believed her.
"Don't listen to athletes when they say it's over," she said.
Nyad likened herself to former boxer Roberto Duran, who retired in 1998 at age 47 only to re-enter the ring a year later.
Nyad denied her problems in the last attempt had anything to do with her age, saying she could have fought through the choppy waves and "excruciating" shoulder pain. But she hadn't anticipated the 11-hour asthma attack that she blamed on a reaction to a medicine she had never used before. She said the asthma had her flailing through the water "like a dying, floundering fish."
Even with those problems, she made it about 50 miles (80 kilometers) into the 103-mile (166-kilometer) haul.
In the ensuing weeks she concluded that the aborted attempt was not so much a failure as a dress rehearsal, an unplanned but necessary part of a training regimen that included a bunch of shorter swims.
"The asthma took me down, but ironically enough, that 29-hour swim was like a very, very expensive training swim," said Nyad, who earlier this year estimated it took a half-million dollars to get her to the first attempt.
"I'm in better shape than before. I'm more prepared than ever," she added.
Without a cage for protection, Nyad is relying on special equipment that surrounds her with an electric current imperceptible to humans but strong enough to keep most sharks at bay. Kayakers also are paddling alongside to gently prod away any that make it through.
For the length of the crossing, Nyad will not be allowed to touch the boat if the record is to count. Nor can her team physically aid her other than to pass her food, medicine, a new swimsuit and so on.
She will try to sustain her energy by eating the likes of peanut butter sandwiches and pasta, and said she sings Beatles, Bob Dylan and Janis Joplin songs in her head to keep her mind occupied, especially during nighttime.
"I never ever it's the cardinal rule I never look up because it's very depressing to see the horizon with no lights, no nothing. And I never ask my trainer here in the boat what time it is or, 'Are we almost there yet?"' Nyad said. "They're going to tell me when we're about 10 hours away."
Nyad first tried to cross the Florida Straits as a 28-year-old back in 1978, when she swam inside a steel shark cage for about 42 hours before ending the attempt.
Now 62, after celebrating her birthday Aug. 22, she has said she hopes to inspire people to lead active lives into their golden years. She also has called the swim symbolic for increasing understanding between the United States and Cuba, two nations torn by five decades of animosity and mistrust.
Marina commodore Jose Miguel Diaz Escrich, whom Nyad described as a cherished friend and who helped with logistics in Cuba, presented her with an honorary membership in the nautical club earlier Friday and called the swim a "bridge of friendship" between the countries.
"He who tries has already succeeded," Escrich said in encouragement, quoting Cuban poet and independence hero Jose Marti.
Nyad's team had hoped to attempt the swim in 2010, but was unable to make arrangements in time. This year Cuban officials were very supportive in arranging logistics and news media coverage.
"We're ready for everything that could possibly come our way this time," Nyad said, "and I just can't imagine any ending other than the ending that I want, which is to get all the way across."
"It's a dream a long time coming."