Diana Nyad’s Cuba-to-Florida swim

The support team accompanying her has equipment that generates a faint electrical field around her designed to keep sharks at bay, and a boat drags a line to help keep her on course.   (Ramon Espinosa / Associated Press)

Nyad, who recently turned 64, tried to swim the Strait three times in 2011 and 2012. She had also tried in 1978.   (Alejandro Ernesto / EPA)

Nyad waves after starting her fifth attempt to swim between Cuba and Florida.   (Ernesto Mastrascusa / EPA)

Nyad began her journey Saturday morning when she jumped from the seawall of the Hemingway Marina into the warm waters off Havana.  (Ramon Espinosa / Associated Press)

Nyad gets ready to swim in a three-day nonstop journey from Havana to Florida at the Ernest Hemingway Nautical Club in Havana.  (Yamil Lage / AFPGetty Images)

Nyad, 64, salutes before her swim. The endurance athlete launched another bid to set an open-water record by swimming from Havana to the Florida Keys without a protective shark cage.  (Ramon Espinosa / Associated Press)

U.S. swimmer Diana Nyad speaks at a press conference held at the Ernest Hemingway Nautical Club in Havana on Saturday. Nyad plans to swim from Havana to Florida in a three-day nonstop attempt.  (Yamil Lage / AFPGetty Images)