One of the world's premier open water distance swimmers is stuck in a waiting game.

The problem for 61-year-old swimming phenom Diana Nyad is that her quest -- a 103-mile swim from Havana, Cuba, to the Florida Keys -- depends on phenomena completely out of her control.

These include water temperatures (which need to be in the high 80s Fahrenheit to avoid hypothermia) and the speed of ocean winds (which need to be gentle breezes so she can make progress against the Gulf Stream).

Those precise conditions only occur few times a year -- during the hot, muggy months of summer.

Last summer, a record number of Atlantic hurricanes kicked up. And delays with Cuban visas didn't help.

So she's back again in Key West, living at the southernmost tip of Florida and dreaming about the swim of her life.

She continues with her open water training -- remarkable 7-hour, 9-hour, 10-hour swims. Her escort boat, Voyager 1, a custom motor catamaran, takes her out from a local marina and she drops over the side. But at her swimming pace--a metronomic 1. 5 miles an hour -- she will need 60 hours of ideal ocean conditions for the Cuba swim to be humanly possible.

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Watch Nyad in the water, droplets of sun-catching water flying off her fingertips, and she can seem deceptively ordinary. She swims freestyle, hands slapping the surface of the water, her kick raising up bubbles. Her stroke is not particularly elegant -- her torso has a wiggle -- but it's strong and steady. If she were in the pool at your local community college, she might blend in with all the other lap swimmers, dutifully going about their workouts.

But spend a little time with her off Key West -- say an hour or so. Especially when the ocean swells pick up. Then, it's pretty clear you are watching a world-class open water swimmer. Even in one- or two-foot waves, she makes progress. On one particular day recently, Voyager 1 had to leave her with a kayak escort to return to port for a quick repair. But Nyad swam on. And her arms never lowered and her pace never slowed. Hour after hour after hour.

Finally, it's becomes clear.

Diana Nyad can swim forever.

"I feel stronger than when I was 25," the 61-year-old Nyad says, referring back to her record-breaking swim around Manhattan Island in 1975. Her stroke may be strong, but aging 35 years has its effects. She's down to about 54 or so strokes a minute from closer to 60, and she's tweaked her freestyle to handle the tiny tears in her shoulders-- shoulders she ices for hours at a time.

At 30, Nyad retired after 10 grueling years of open water swimming. She had traveled the world competing and had accomplished many of her goals, including the longest open water swim at that time--a 1979 effort of 102.5 miles from Bimini to Florida. But the Cuba swim had bedeviled her. Nyad 's 1978 attempt of this same swim ran afoul of weather conditions. Strong Gulf Stream currents pushed her well to the east, and in the end she could not make progress against 9-foot waves. She was tough and determined, but nature had made this swim simply impossible to do.

That doesn't mean other swimmers haven't tried -- and debates around this Cuba swim are part of the sport. In 1997, for instance, 21-year-old Susie Maroney, an Australian open swimmer, left Havana and swam into U.S. territorial waters in 39-hours. But an exhausted Maroney (who was later rushed to the hospital) stopped her swim off-shore -- 12 miles south of Boca Chica Key. Does she hold the record for swimming from Cuba to the United States or not?

After she retired from swimming, Nyad became a journalist. A gregarious and gifted storyteller, Nyad has spent much of her life covering sports. She's worked for a wide range of organizations -- from ABC's "Wide World of Sports" to "CBS Sunday Morning" to the New York Times, CNN and NPR. In her spare moments, she's penned three books, started a fitness company with her close friend Bonnie Stoll, and stayed physically fit --though she says she did that without swimming a stroke for 30 years.

Two years ago, the death of her 82-year-old mother brought up the Cuba swim again -- amidst what Nyad calls "an existential crisis" and evaluation of her life goals. Was she, in fact, living her life large enough? She says she decided to revisit this swim as a task so consuming it would, in a way, drive out her demons of aging and mortality. "I wanted something so challenging that would occupy all of me," Nyad says.

Swimming from Havana to the Florida Keys should take care of that.

To make this swim, Nyad will be in the water 60 hours without any kind of wetsuit insulation -- or swimming aid. As soon as she enters the water on a beach near Havana, she and her experienced ocean navigator, David Marchant, must play a cat and mouse game with the Gulf Stream -- the powerful ocean current that will constantly threaten to push her eastward.

"I don't like to tell her this, but I believe the currents may push her to swim longer than the 103 miles," says Marchant, who will be reading marine charts and a satellite navigation system and weather reports for the entire sixty hours. He's charged with relaying precise course headings to the escort boat driver. Like Nyad, he won't have the option of being off-duty.

The rest of her 25-person team all have unusually stressful jobs, focused on specific support tasks. Round the clock, there will be a team of kayakers, who must paddle near her right hip the entire way. The kayak carries a shark shield underneath it -- an electrical device that disrupts and disturbs a shark's ability to locate prey by throwing out a circle of electrical current.

Sharks are a notorious threat in these waters, and shark cages are sometimes used by swimmers -- Nyad used one during her original attempt and Maroney used one for almost 20 miles before abandoning it. Instead of the claustrophobic protection a cage provides, Nyad will rely on her electric shark shield -- as well as a team of divers who may need to prod aggressive sharks away from her.

Even driving the escort boat is an incredible marathon ordeal, requiring precise steering and throttle control. The custom catamaran Voyager 1 has smaller propellers to keep its speed at Nyad's freestyle crawl pace--and a parachute-like drogue is deployed off the back to keep it slow even when ocean currents speed it up. "It's incredibly difficult to drive the boat this slowly," said Maya Marchant, David's wife, explaining that she must keep Nyad positioned inside a 10-foot zone alongside the boat.

Since deciding to the do the swim, Nyad's training has included a gym regimen. She favors workouts with light weights and yoga-like stretching. She has also built up her weight to almost 150 pounds, which will give her both the strength and insulation for the grueling effort. But, as is the case for most swimmers, the real training lies in hours of open water swimming -- including stints earlier this year in the warm waters off St. Maarten.

"I really don't know how many training swims I've actually done," Nyad says, but they have both honed her stroke and given her the mental toughness to pursue the big swim.

They have also provided crucial practice for her support team, which will need to literally be by her side every step of the way. Head trainer and best friend Bonnie Stoll will oversee a rotating four-person team during the Cuba swim. Now, she handles most of the duties of communicating with Diana during her training swims and making sure her nutritional and safety needs are met.

About every 90 minutes, Stoll will signal to Nyad, who swims about 15 or so feet from the side of Voyager 1. With her head turning to breathe and then lowering back face first into the dark green ocean, Nyad follows a 5-inch wide piece of white sail cloth dropped into the water from a boom hanging overhead. The cloth functions like a lane line in a swimming pool. It enables Nyad to avoid the effort to keep the side of the boat constantly in her peripheral vision.

By the rules of open water ocean swimming, Nyad cannot hold onto the boat or use a flotation device to rest. When Stoll signals her over to eat and drink, Nyad treads water, pushing her swim goggles--smoky or tinted during the day, clear at night--on the top of her head. She blinks in the daylight, as if caught off guard or awoken from sleep, and her body rises and falls in the swells. She takes a relaxed almost seated position, and her white legs swirl underneath her.

Holding a camelback water bag in one hand, Stoll extends Nyad a tube that she clamps in her mouth. The swimmer must constantly hydrate, especially in salt water, and the camelback holds a mix of water and sports drinks and electrolytes. Like a marathon runner, Nyad also will take a variety of gels and goos--all easily digestible. If her stomach can manage it, she may take a banana with peanut butter, but that can be a struggle if the water is choppy.

To meet her energy needs for the swim, Nyad knows she must take in just under 1,000 calories an hour, or risk her muscle proteins being depleted by the extreme energy requirements of her swim. Watch her routine and you can only think of those military jets that must be refueled in flight. The nutritional requirements have real consequences--after a 24-hour practice swim last summer, Nyad vomited numerous times and underwent intravenous transfusions to replace lost body fluids.

The physical dangers do not end there. Her on-board physician will be concerned with the dehydration and hypothermia -- and even the possibility of a kind of hallucinatory delusional state caused by the swim's sensory deprivation and physical exertion. Nyad may also need to be treated for Portuguese Man-of-War stings--all from the side of the boat.

The mental duress, though, may be the toughest part.

Nyad has invented a wide range of ways to occupy her mind as she swims. She plays counting games--in English, Spanish, French, and German. She sings a wide range of songs, from the theme songs of television shows like The Beverly Hillbillies to Bob Dylan songs. From the side of her escort boat, you can sometimes hear Nyad's voice waft over the ocean...telling herself stories, or even grappling with philosophical questions. In the end, though, observers say she seems to go into almost a kind of swimming trance.

"Michael Phelps could physically do this swim," notes Stoll, watching Nyad during a recent swim. "But, could he mentally stand being in the open ocean for 60 hours straight."

Nyad 's many supporters believe she may be one of the few people on earth who can handle that feat. But only if ocean conditions are right.

Until then, she trains off Key West. And waits.

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