SYDNEY  - An Australian open-water distance swimmer who has made multiple crossings of the English Channel on Sunday announced an ambitious bid to swim solo from Cuba to the United States without a shark cage.

Chloe McCardel, 27, has twice won the Channel Swimming Association's Sotiraki Cup for the fastest swim by a woman across the strait between England and France -- in 2011 and 2012 -- and has also won the gruelling Manhattan Island Marathon.

But McCardel has set an even loftier goal for 2013, unveiling plans to swim a daunting 170 kilometres (106 miles) solo and non-stop from Havana in Cuba to Florida's Key West in some 60-70 hours.

If successful she will set a new world record for longest solo unassisted ocean swim, currently held by British-Australian Penny Palfrey for a 108-kilometre swim without shark cage or wetsuit in the Caribbean in 2011.

For the first time in history McCardel hopes to complete the testing Gulf Stream and Florida Straits crossing without the protection of a shark cage, compounding the difficulty of her daring feat. "It is a great time of year to make this announcement, when so many people are celebrating the New Year and thinking about their own dreams and aspirations for the next 12 months," said McCardel, who conceded her mother would probably "faint" after hearing her plans.

"I really hope I can inspire more people to push their own boundaries or perceived limitations." American distance swimmer Diana Nyad, 63, was plucked from the water halfway across the same route earlier this year due to storms, hypothermia and jellyfish stings -- her fourth attempt at the challenge.

McCardel's June 2013 swim will raise funds for cancer research and support services and she has said no sharks will be harmed "by the conduct of anyone involved during the swim". A conservationist will be on board the support vessel. She is expected to encounter plenty of the marine predators as well as strong and unpredictable ocean conditions, jellyfish and potentially wild storms.

The Australian will only wear a basic swimming costume and will be banned from touching the boat or another person, or using flippers, a snorkel, wetsuit or any other flotation device.