As a boy, Ben Hooper idolized British adventurers who achieved the impossible. Now, he plans to become one of them by swimming the Atlantic.

Hooper, 38, has prepared for three years for his mission, which will require him to swim up to 10 hours a day for nearly five months.

He will leave from Senegal on Tuesday followed by a support boat with 11 crew members, including a medic, and stocked with military food packs and energy drinks. He plans to touch land on Brazil's east coast.

"Shark-wise, we have two lines of defense," he said, explaining that he will carry synthesized rotting shark meat, while cables in the water will send out an electrical signal to ward off the predators.

A bout of depression led Hooper to leave a career with the police in his late 20s to study psychology, but the depression returned three years ago and he realized something had to change.

He began looking back to the fearless English explorers: Ranulph Fiennes, who reached both the north and south poles overland, and Vivian Fuchs, the first man to cross the Antarctic on foot. "Fiennes has been an inspiration of mine since I was a teenager," he said, adding that he received a letter from the explorer in his mid-teens. "He sent me loads of information."

After some thought, Hooper dared himself to become the first man to swim the Atlantic.

Reaction to his plan has been varied, not least because he is far from a professional athlete. "I'm not ripped like (US Olympic champion) Michael Phelps," he said, patting his slightly round stomach.

However, he said, what keeps him hitting the gym and pool every day is his 8-year-old daughter, Georgie. "Every time I talk to her she ... makes me realize I'm a worthwhile person," he said.

So how does he reconcile putting himself at such risk?

"A couple of weeks back, I did think about death, but... if you don't step outside the box once in a while, the lid's going to close on you."