Less than two months after ending her attempt to swim from Cuba to Florida because of health problems, Diana Nyad is trying it again.

The 62-year-old marathon swimmer began the 103-mile swim on Friday evening in her latest attempt to become the first person to swim that route without a shark cage. If all goes well, it will take her about 60 hours to reach the Florida shore. The rules for setting the record are that she can stop to eat and drink once an hour and she can tread water if she needs to, but she can't touch the boat that is accompanying her at any point during the swim.

About 30 people are monitoring her, both to keep away sharks and to help her in a medical emergency.

She had been swimming for 27 hours as of 9 p.m. on Saturday, and she was about 50 miles from Havana, Cuba. Already, she has run into some obstacles, including multiple stings from Portuguese men o' war Friday night.

Diana was stung along both arms, the side of her body and her face, Nyad's blog reported. Jonathan Rose, a safety diver and EMT, immediately got in the water with Diana to try and free her of the tentacles and stingers. Rose was also stung numerous times. The crew got Diana's swimsuit changed and put a new suit on with a shirt covering her. After an hour and a half of treading water, Diana began to rehydrate and swim her freestyle stroke.

Since she got past that, the waters have been calm for Nyad, and she is still swimming toward Florida.

Nyad last attempted this swim in early August, but she was forced to stop after 50 miles and 29 hours. She suffered periodic asthma attacks for 11 of those hours and severe shoulder pain toward the end, and she was vomiting by the time she finally agreed to stop and get onto the boat.

Before her second attempt, she wrote on her blog about how she keeps herself occupied for such a long time in the water. No one could swim the whole thing while thinking about the whole thing, she wrote. Till I get a glimpse of the final shore, I can't start obsessing on it -- it's too far away, too nebulous -- I don't know where it is.

So instead, each evening, she comes up with a list of songs and things that she'll think about while swimming to get her through the night. After the first night, now my job is the daylight. And I'm going to start over as if that nighttime never existed and begin a new series of counting and songs and then put that behind me like it never existed, then the night again and the day... and there's going to be another night, I guess... and I'll just do that till I get news that the shore is near.