The ocean current worked against him, getting stronger the closer he got to shore. So, even as his distance to the coastline decreased, his time to get there remained the same, for hours. His crew, with GPS and fancy instruments, would share the bad news with him every 20 minutes when he would tread water to drink from a water bottle they tossed.
"I felt like crying every time they told me the news," he said. "It was so crushing. I never did cry."
He just suffered.
Thirteen hours in a cold ocean, much of it in the dark, worrying a fair amount about great white sharks, since one had just attacked a swimmer three weeks earlier nearby.
"I forgot how painful swimming was," he said Monday before boarding a plane home. "I'm sounding tired and whiny and complaining today, but inside I'm shocked and in awe and amazed. There's a real high that's going inside of me right now."
McCarley, who runs InteHealth, a health-focused software company in Malvern, is part of an expanding and aging group of marathon swimmers, about 8,000, many in their 40s and 50s.
"Our sport is growing, and it's becoming older and slower," said Steven Munatones, editor of the Daily News of Open Water Swimming.
He said 93 people have completed this triple crown, though "40 percent of them have done it in the last four years." Fewer than 10, he said, have done all three within 12 months, like McCarley.
The sport tends to attract goal-oriented, introverted people with incredible willpower, Munatones said.
"Sensory deprivation is immense," he added. "The whole exercise exists in your mind."
McCarley strives to practice lap after lap, hour after hour, at the exact same pace; he finds the experience meditative. He can also do a lot of thinking about work.
Marathon swimming is defined as distances in open water greater than 10,000 meters, or six miles. An estimated 12 million people worldwide participate in the broader sport of open water swimming, Munatones said.
Marathon swimming attracts older participants in part because it can be expensive. For the Catalina swim, McCarley rented his support boat for $3,200. The entry fee for the Manhattan swim, which supplied a support boat, was $2,500.
Marathon swimming can lead to immense personal satisfaction - and also true love.
Jason Malick, 31, who lives in Wilmington and Avalon, N.J., organized a swim in 2011 across the Delaware Bay, from Cape May to Cape Henlopen, believed to be the first in 100 years. He led a group of five swimmers, but only one succeeded.
Malick also organized a 15-mile swim around Cape May last fall, in which McCarley participated and completed just three weeks after his English Channel swim, giving him confidence that he could complete the Manhattan and Catalina events so close together.
In January, Malick entered the Frogman Swim - a 5000 meter swim (3.1 miles) in 56-degree Tampa Bay.
There, he met Lisa Hertz, 29, a former Franklin and Marshall College swimmer.
"We were two of only three people out of 150 that weren't in wetsuits," he said.
Love was found in the frigid water. They began dating and supporting one another in open water swimming.
She swam 24 miles in Tampa Bay in April and he paddled beside her in a kayak as protector. And then she was on his support boat as he, like McCarley, also swam 28.5 miles around Manhattan on July 12.
Moments after finishing, "I popped the question on the dock," Malick said. "Luckily she said yes." Of course, the engagement ring is a white gold dolphin with an aquamarine in it.
"We plan on honeymooning in Hawaii," he added, "and each swimming the 26-mile Molokai Channel between Molokai and Oahu."