Inside Diana Nyad's new Cuba-Florida swim strategy

(CBS News) Long-distance swimmer Diana Nyad is eager to catch her last hurrah of summer. On Saturday, she will try to swim across the treacherous waters separating Cuba from Florida - an attempt she's failed to complete four times before.

But now, she has a new strategy.

At 64 years old, Nyad couldn't resist the call of the ocean one more time. She's tried the 103-mile swim from Cuba to Key West four times. Each time she's come up short.

So why is she making the attempt again? She told CBS News' Elaine Quijano, "I just hadn't reached the end. I hadn't reached the wall where there's nothing more to give. If I don't make it, I will this time be able to look myself in the mirror and say, 'There's nothing more.'"

No one has successfully swum the Florida straits without a shark cage. Nyad's first attempt to cross those shark-infested waters was in 1978. Nyad said then, "I did my best. It didn't come out."

Her recent swims were derailed by stings from box jellyfish, one of the ocean's deadliest creatures. On this attempt, she will wear a full body suit and custom face mask to protect against the venomous stings.

Nyad said, "The box jellyfish takes you into an area of what I'd call science fiction. You feel like you've been dipped in hot burning oil. You burst into flames."

The swim could take more than three days to complete. Nyad will be accompanied by a support crew of four boats and 40 people that will help her navigate the changing weather and unpredictable ocean currents.

John Bartlett, Nyad's navigator, explained the swim is so complicated because swimmers travel slowly in relation to the speed of the current. "We're going to be going through currents out there that would be three times the speed that we travel," he said.

Pauline Berry is in charge of keeping Nyad fueled for her swim. Using a hydration pouch, Berry and a team of handlers will feed Nyad a steady supply of protein mixtures and electrolytes. "We're looking for dehydration, signs of confusion," Berry said. "We want to make sure she's keeping her diet up the best she possibly can."

If Nyad doesn't make it this time, she told CBS News, "I'm sure I won't be in the mood to have a party momentarily, but I will feel proud. I will feel proud. I'll feel like the journey was worthwhile."

Watch Elaine Quijano's full report above.