HAVANA, Cuba- Endurance swimmer Diana Nyad is forging ahead in the straits of Florida in pursuit of a record 103-mile unassisted swim.

This is the third attempt in a year by the 62-year-old Californian to swim from Cuba all the way to Florida.

At a pace of 50 strokes a minute it will take Nyad at least 60 hours to complete her journey.

She is expected to arrive in the Keys Tuesday mid- morning.

Nyad is struggling with the muscle fatigue, a powerful ocean current, sharks and painful jelly fish stings.

During her swim Nyad takes short breaks to rest, hydrate and eat.