Lynne Cox’s Next Challenge : Swimming: She’s planning to attempt to cross icy strait between Argentina and Chile.

Political and weather conditions permitting, Lynne Cox of Los Alamitos plans to swim the icy Beagle Channel from Argentina to Chile as early as Saturday.

The five-mile-wide strait at the tip of South America has long been a disputed border between the countries, virtually from when Charles Darwin did studies on evolution there in the 1830s. The channel was named for his ship, the Beagle.

This would be Cox’s third major “goodwill” journey, after her crossing of the Bering Strait from Alaska to the Soviet Union in 1987 and her swim in Soviet Siberia’s Lake Baikal in ’88.

Cox, 33, said Thursday from Ushuaia, Argentina, that in training swims since her arrival on Dec. 27, the water temperature has varied from 40 to 46 degrees, similar to what she encountered in the Bering Strait.

That was a shorter swim, requiring about two hours, but she has worked up to three hours in training in the Beagle Channel.

Ushuaia is the southernmost city in the world, with only sheep ranches farther south.

“It’s an incredibly beautiful area, with glacier-covered mountain passes,” Cox said. “They can block the wind or intensify it. The conditions here are so changeable that in 20 minutes you can go from a flat calm to gale winds up to 30 knots.”

The political climate also remains unstable, especially on the Chilean side.

“Yesterday I was ready to call the whole thing off,” Cox said. “The border here is so intensively sensitive (that) it was a lot easier to get permission from the Soviets to swim across the Bering Strait than to get this together.”

Cox said the Argentines--particularly Navy Capt. Hector Alvarez--have probably been more cooperative than the Chileans because she has been based in Argentina during her training.

“Maybe it would be different if we had spent the time in Chile and gotten to know the people there and have them understand the whole concept of this--the sport, the medical (experiment), the good will,” she said.

“The Argentines have the full concept. We should have gone to Chile and let them get to know us as people.”

The Chileans will not allow Argentine boats into their side of the channel. The plan is for Cox to be escorted by an Argentine naval vessel to the halfway point and from there by a Chilean boat.

Alongside her on a paddleboard, as he was at Lake Baikal, will be Ross Roseman, a commercial pilot and former fellow swimmer at Los Alamitos High School.

Cox also will have inflatable boats on either side--one a Chilean boat with her medical support team, the other an Argentine boat with media personnel and coordinating aide Barry Binder of Long Beach. Binder must transfer to a Chilean boat in mid-channel.

The Argentines have agreed to permit the Chilean Zodiac to come all the way across to pick up Cox’s medical team, so they won’t have to transfer halfway.

Dr. William Keatinge, an expert on hypothermia from the London Medical College, and his assistant, Penny Neild, will monitor Cox’s condition through a transmitting “thermo pill” she will swallow before stepping into the water.

Keatinge used a similar method when he accompanied Cox on her Bering Strait swim.

“There is one major complication,” she said of the thermo pill. “We’ll be starting from an area where they do radio transmissions, and (in training we learned that) when they turn on the thermo pill, they get rock music.”

Cox said the local people have been wonderful during her training period.

“To them it’s absolutely astonishing,” she said. “To them, 10 to 15 minutes (in the water) is max.

“It’s going to be on the fine edge of where it’s safe to do it and where it’s beyond reason. It looks like it might have been a better course to go from Chile to Argentina, the way the winds and currents are. But we’ll go with what has been established.

“This is going to be a rough one.”