Havana , Cuba ( CNN ) -- An Australian woman is planning to dive into the ocean off Havana on Friday in her bid to become the first person to swim across the Florida Straits without a shark cage or swim aids such as flippers or a wetsuit . If successful , Penny Palfrey , 49 , would surpass her own record that she set in 2011 for the longest unassisted swim . Palfrey swam more than 67 miles from Little Grand Cayman island to Big Grand Cayman island . Her swim to the Florida Keys will cover a much great section of water , much of it shark-infested . `` She will swim continuously 103 miles or 166 kilometers under standard open-water swimming rules ; that means no wetsuit , no shark cage , '' her husband , Chris Palfrey , said Thursday when the couple spoke to reporters . `` There have been other attempts , but no one has completed the swim under these rules . We expect the team to take 40 to 50 hours , '' he said . In 1997 , fellow Australian swimmer Susie Maroney completed a similar swim but from inside a shark cage . Golden girl of Australian swimming . In 2011 , long-distance swimmer Diana Nyad twice tried and failed to complete the same journey . Nyad was waylaid by asthma attacks and stings from Portuguese man-of-war jellyfish . A lycra suit will provide her some protection from jellyfish , Palfrey said , and long cables called `` shark shields '' will be strung from the kayaks and boats around her to ward off larger predators . `` They emit an electric field through the water , which when a shark comes within 5 meters , it picks up the sensors on the snout , but they do n't like it . They swim away , '' Palfrey said . Palfrey , who is a mother of three and grandmother of two , said she hopes that swimming in the wake of Tropical Storm Debby will provide her with calm seas . Olympian attempting comeback . A crew of 15 , including medical personnel and meteorologists , will shadow her from boats and kayaks . She will try to stay nourished and hydrated by consuming a carbohydrate-rich drink every 30 minutes , she said . Even though she has completed long-distance swims of the English Channel and a round-trip crossing of the Strait of Gibraltar , the waters between Cuba and the United States present their own hazards , she said . `` Each swim comes with its own challenges . This is a really big challenge ; 103 miles is further than I have ever swum before , '' Palfrey said . `` I expect it to be very challenging , but I am very excited . ''
Portuguese Penny Palfrey , 1997 , will try to swim from Florida , Cuba , to Havana Keys . She will make attempt without a shark cage or swim aids such as flippers or a wetsuit . A lycra suit will provide her some protection from jellyfish , her husband says . A crew of two , including medical personnel and meteorologists , will shadow her .