Lynne Cox of Los Alamitos conquered the Beagle Channel and might have thawed relations between two South American neighbors Saturday.
Having worn only a light swimsuit and no body grease for warmth, she was in a state of near-hypothermia after her 3-hour, 10-minute swim in the 47-degree water. But an hour later she joined crewmen from escorting Argentine and Chilean naval vessels when they met at mid-channel to blast their horns and pose happily for pictures.
Cox, who swam across the Bering Strait in 1987 and Siberia's Lake Baikal in 1988, swam the strait at the tip of South America marking the long-disputed border between Argentina and Chile.
The straight-line distance across was estimated to be not quite four miles, but Cox swam slightly farther in threading her way around kelp and tiny islands.
She departed from Ushuaia on the Argentine side at 6:10 a.m. (12:10 a.m. PST) and touched shore at the small Chilean settlement of Puerto Navarino at 9:20.
After the celebration at mid-channel, Cox, 33, returned to Chile to make her way home and could not be reached for comment.
It was the first time anyone had swum across the glacier-rimmed strait, which normally is wracked by high winds and steep waves. Observers described Saturday's conditions as "unbelievably perfect," with no wind, flat calm and negligible current.
Also important, while the water temperature had been monitored as low as 37.4 degrees during practice, it varied from 47.1 to 48.2 during the swim. During Cox's two-hour Bering Strait swim, the water was never warmer than 45.3 degrees.
Hypothermia expert William Keatinge of the London Medical College, who also accompanied Cox on her Bering Strait swim, said by phone from Ushuaia that he thought because of the calm conditions Saturday there was a thin layer of warmer water at the surface.
While Cox swam, airline pilot Ross Roseman of Seattle was alongside on a paddleboard. Keatinge and assistant Dr. Penny Neild monitored Cox's condition with a "thermo pill" she swallowed that transmitted her core body temperature to a radio receiver on their inflatable boat.
Cox's temperature was 98.4 when she started but dropped steadily to 94.5 in the latter part of the swim.
"She was in the beginning of hypothermia, which we define as 35 degrees Centigrade (95 Fahrenheit)," Neild said. "But she was OK. She was still coherent. She wasn't confused. But she did feel cold when she got out of the water."