The cold nearly killed him, gradually shutting down his organs as each stroke of his marathon swim sent blood-chilling water over his near-naked body.
Then, with his arduous crossing across the Catalina Channel almost complete, the conditions cruelly worsened, as if not to let him escape.
Ron Collins can't remember what happened next.
He's been told that his support team pulled his numb, limp, doughy-white body from the ocean just as his temperature plunged to critically dangerous levels.
"They saved my life," he said.
The Catalina Channel is one of the world's most popular open-water swims, with dozens attempting to cross from the mainland to the island shore each year.
But it's also among the most challenging — some 20 treacherous miles of navigating kelp beds, sharks, jellyfish and winds that can unpredictably sway the currents.
Collins, 48, is a highly trained and accomplished open-water swimmer who had already conquered longer (28 miles around Manhattan Island) and more famous courses (the chilly, 21-mile English Channel). Yet, even though he prepared for Catalina by swimming up to 30 miles a week, he couldn't handle the prolonged cold.
And that's the biggest challenge for a relay team of three local men and one woman who on Monday are planning to launch the first attempt in the world at four consecutive channel crossings — from points in the South Bay back and forth to Catalina's shore — in support of Jay Nolan Community Services, a foundation that serves the autistic and others with developmental disabilities.
The relay, which in a straight line would be about 80 miles, stretches to more like 100 when the ocean's current is calculated. To that, add another daunting problem:
Typically, the water in the channel is about 70 degrees. But even with this week's triple-digit air temperatures, the water along the Southern California coast has been in the low-to-mid 60s — "the coldest I've ever seen it," said John York, founder of the Catalina Channel Swimming Foundation, who has swum the channel six times.
That's a big reason why the success rate in attempted channel crossings has plummeted. Each year, 80% to 90% usually make it, but this year 24 have made it, 12 have not.
The water temperature was 55 degrees in early September when Collins' swim ended.
A chilling statistic indeed.
Chris Dahowski was working out at his local gym about 18 months ago when he overheard a few triathletes discussing a relay swim to Catalina.
He wanted in; they said no. "Fine," he thought.
So Dahowski, 43, of Valencia, recruited for his own relay team his friends in the Santa Clarita Triathlon Club: Michael Vovk, 43, of Castaic and David Hartmire, 49, of Newhall, plus Jen Schumacher, 25, from Irvine, who had already swum the Catalina channel.
For about four months, they've been swimming five or more days a week — some sessions in a pool, others in the ocean. Each has usually totaled about 15 miles per week, though they've upped that in recent weeks.
To prepare for the cold, Dahowski, Vovk and Hartmire have been swimming in the sub-60 waters off Ventura County — Schumacher has done cold-water training, too — hoping it will help their bodies acclimate.
For long-distance swims, proper training is needed to help stave off advanced hypothermic stages if the waters are below 70 degrees, said Dr. Jim Miller, a national team physician for USA Swimming. That's a certainty for the Catalina swim, which on average takes 13 hours for one crossing.
To keep warm, swimmers use earplugs and a thicker silicone swim cap in addition to a latex cap. Wet suits are not permitted, according to the Catalina Channel Swimming Federation rules.
Hartmire, who took up triathlons to lose weight, said he has been downing "big lunches and extra desserts," trying to add about five pounds of fat to help insulate his body.
Then there are the obstacles beyond the cold.
Midnight is the ideal time to start the Catalina swim. Winds then are typically calm for about 12 hours, leaving the ocean peaceful.
But Hartmire, on the first leg of the relay, will begin at noon, and there are concerns that winds could turn his swim into a 20-mile battle against two-foot waves. The same goes for the third swimmer, Schumacher, whereas conditions favor the second (Vovk) and fourth (Dahowski) swimmers.
All four might encounter marine wildlife, but Steve Blair, the Aquarium of the Pacific's assistant curator and shark expert, says sharks off California's coast are rare because they've been overfished.
Even if the swimmers do see one an attack is unlikely, Blair said. Since the 1920s, fewer than 10 people have died by shark attack in California.