(CNN) -- She has been scorched by the sun, stung by jellyfish and inspected by sharks. But Penny Palfrey keeps swimming.
Palfrey, 49, is vying to be the first person to swim 103 miles across the Florida straits without any assistance -- no shark cage, flippers, wet suit or snorkel.
And even though she has been in the water since Friday morning, the Australian-British dual citizen and grandmother of two shows no signs of quitting.
"Her mental and physical state are reported as strong," read a message on Palfrey's Facebook page Saturday afternoon.
"She reports no physical complaints," the crew reported. "She is still the boss in the water. She is all business."
As of 4 p.m. Saturday, Palfrey had swum 69.05 miles, breaking her record of 67 miles set in 2011 while swimming from Little Grand Cayman island to Big Grand Cayman island, the posting said.
Earlier Saturday, a meteorologist helping Palfrey's team told CNN he thought she would complete the swim between Cuba and the United States. "She is looking very strong and strong after 24 hours in the water is a good thing," meteorologist Bill Cottrill said.
"She has the best chance to make it," according to Cottrill. "I would say weatherwise there is no reason she shouldn't be able to."
Cottrill told CNN said the team expects Palfrey to complete the journey late Sunday afternoon. The Gulf Stream current added about 18 miles to her swim.
In 1997, 22-year-old swimmer Susie Malroney completed the feat, using a shark cage.
Last year, swimmer Diana Nyad twice tried to make the swim, also unassisted, but was turned back by health problems and stinging jellyfish.
A crew of 15, including medical personnel and staff updating Palfrey's social media pages, are following her in boats and kayaks.
She will stay nourished and hydrated by consuming a carbohydrate-rich drink every 30 minutes.
The crew also employs "shark shields," cables that hang from the boats and kayaks around Palfrey and emit a pulse designed to keep the predators at bay.
"We attach [the shields] to the kayaker and to the boat which emit an electric field through the water," Palfrey told reporters in Havana on Thursday. "When a shark comes within five meters it picks up the sensors on the snout. It doesn't harm them, but they don't like it and swim away."
According to the Facebook posting on Satuday, the devices may have come in handy after Palfrey spotted hammerhead sharks swimming beneath her.
The sharks, though, "quickly vanished," according to the posting.