Randy Alcorn tells the story of Florence Chadwick, the famed 20th century ocean swimmer, in his book Heaven. At the age of 10, Chadwick became the youngest person to swim across the mouth of the San Diego Bay. Later, she became the first woman to swim the English Channel in both directions and set a record for the England-France leg of the swim.
In 1952, Chadwick attempted to swim the 26 miles between Catalina Island and the California coastline. Fifteen hours into the swim, a thick fog settled over the coast. Chadwick could no longer see the boats that were traveling near her to provide safety and assistance, much less the shoreline to which she was swimming. Her mother called from a nearby boat, reassuring her as she swam under such difficult conditions. But after another hour of swimming, Chadwick asked to be pulled out of the ocean.