August 24, 1987 12:00 PM

In addition to being the world’s best female endurance swimmer, Lynne Cox has powers of positive thinking that make Pollyanna sound like a sourmouthed grump. As she jumped into the frigid, fog-shrouded waters of the Bering Strait last week, Cox yelled “Great! It feels great!” as though a life-threatening swim in the 43°F briny (two degrees colder than refrigerator ice water) was just what she needed. In fact, Cox, 30, knew that the 2.7-mile swim across the superpower strait—from Alaska’s Little Diomede Island to Big Diomede Island off the coast of Soviet Siberia—would be the toughest challenge of her career. By the time the cold-water warrior clambered ashore into the arms of a Soviet welcoming party, she had spent two hours and six minutes in waters that can freeze an average human to death in 30 minutes. The demurely modest Cox beamed for the cameras and allowed everyone to think it had been easy for her. Only later did she admit that pain and fatigue had almost forced her to quit. “It was the riskiest, most frightening, most difficult thing I’ve ever done,” said Cox.

Her feat was the longest intentional cold-water ocean swim on record and a diplomatic triumph. Before she got to brave the waves and the strait’s treacherous weather, Lynne had beaten down some Cold War political obstacles. The Soviets had not allowed Americans to set foot on the barren islet of Big Diomede since 1948. Cox’s appeal to the Kremlin met with silence for more than a year until, days before the swim, the Soviets—in a burst of glasnost good-heartedness—gave permission.

As she began knifing through the water in her fast freestyle, Cox was in a race against time and the cold. She was not wearing a wet suit or a layer of lanolin, grease which might have attracted sharks, so she had to swim fast and finish before the ocean leached the heat from her heavily-muscled, 180-lb. body. “I was swimming faster than I ever swam before—really sprinting,” she says. “I had to move as fast as I could to generate heat.” She had swallowed an electronic thermosensitive capsule so doctors and scientists in one of two walrus-skin escort boats could make sure her temperature did not fall dangerously low. Unaware that Cox, raised in Los Alamitos, Calif., once held the record for the fastest crossing of the English Channel (9 hours, 36 minutes), local Eskimos were skeptical that she could beat the Bering. “I put my hand in the water every time we go out in the boat,” remarked Percy Milligrock, an ivory carver. “It’s cold. I think they’ll have to pull her out.”

Early on, Lynne met another doubter, a spotted seal, who studied her intently. Cox laughed to herself: “I could see he was wondering ‘What’s she doing here?’ ” Soon enough, she had stopped feeling cheerful. After battling an icy two-knot tide for 90 minutes, her toes had gone numb and her hands were in constant, stinging pain. The shore of Big Diomede was only 50 yards away, but the water temperature had dropped to 38°F and the current was picking up. “The sea was like a washing machine, churning up the cold water from below,” says Cox. “I said to myself, ‘God, what happens if the current sweeps me back out to sea? With the fatigue and the cold I won’t be able to fight it.’ At that point, I was afraid I wouldn’t finish. I didn’t want to say how bad I felt,” she admits.

Still, she kept swimming, paralleling the rocky coast for half a mile to reach the official landing site at the foot of a snowbank. Finally she staggered, blue and shivering, out of the breakers, to be engulfed by the kisses and applause of admiring Russians. But her ordeal was not quite over. Unaware that Cox’s core body temperature was falling, the hospitable Russians held an impromptu press conference before leading her to a warming tent. “It was overwhelming on the snowbank,” she says. “Microphones, people throwing towels, the realization that we’d made it—we were in the Soviet Union! But my legs were trembling and I felt I was going to fall down.”

Once ensconced in a warming bag, Cox began to regain feeling in her limbs, while Soviets and Americans’ gathered outside td celebrate her triumph. Cox was elated. She had completed another punishing swim, but it was that unaccustomed image of U.S.-Soviet harmony that would linger longest. “It was one of those rare occasions in life when things turn out better than you ever imagined,” she said. “And I could see from the eyes of the Russians that it was special for them too.”