In many ways, Zac Sunderland looks, acts and talks like any 17-year-old boy.

His hair is stylishly long and sun-bleached. His lanky frame and face are hidden by baggy pants, skateboard T-shirts and a ball cap. And yet, there's something behind his slow, So Cal accent that betrays his laid-back attitude. A quiet confidence, an occasional excited edge to his voice, a matter-of-fact determination that combine to give him an aura of someone twice his age. And if you don't know who Zac Sunderland is yet, you will soon. He'll make sure of it.

In July, Sunderland became the youngest person ever to sail around the world alone. And by the time he landed at Marina del Rey, Calif., 13 months later, Sunderland had appeared on the cover of ESPN the Magazine, finished a book about his experiences and become an international celebrity. Sunderland downplays the obstacles, but it's his near failures that shaped him and make his story a remarkable example of perseverance.

Before he could hit the open waters, Sunderland needed a boat and his parents' blessing. The Sunderland family grew up on the water. Zac's first house was a boat, and his dad was a lifer in the business, running boats up and down the coast of California. His parents were comfortable with Zac's sailing experience.

Boats equipped to sail around the world don't come cheap, though. Sunderland sold repaired dinghies and helped with his dad's business, saving almost every dime he made. 'When I found Intrepid, for the price she was and the condition she was in, she was worth maybe $20,000,' Sunderland says. 'I managed to get her for $6,500.'

Intrepid was in good shape but wasn't ready for the rigors she would face. Sunderland worked 16-hour days for almost two months as he, his dad and the occasional friend stripped the boat down to the hull. They changed all the electrical and plumbing components; installed new navigation, communication and meteorological equipment; repaired and repainted the shell; they even replaced the mast using a yacht crane they borrowed.

All the while, Sunderland was trying to nail down sponsors, sending out proposals, asking industry reps for help, and just trying to get anyone to believe in him. 'The main obstacle was making everyone take it seriously,' he says. 'Everyone has an idea for something, but trying to convince people that I was going to do this trip [was difficult].'

On June 14, 2008, Sunderland pushed off, heading west, seeking adventure and a record. 'It was amazing to switch modes from working 16-hour days to just chilling on a boat and sailing along. It was borderline overwhelming, getting ready to go, but I was also psyching myself up for this big challenge I was facing.'

Sunderland's journey encompassed roughly 28,000 nautical miles. It was peppered by stops in exotic locales—Australia, South Africa, the Panama Canal—and close calls that tested his very will to survive. His long, lonely days at sea pushed his resolve to the limits. He rarely ate, dropping 50 pounds over the course of the trip. His sleep was uneven and interrupted by alarms from his radar and weather monitors. All of those experiences chiseled a self-reliant man from the boy. 'When you're the only one in a situation, there's no one there to help you; you have to be reliant on yourself,' he says. 'The ocean doesn't scare me. I have respect for it, but I can pretty much control any situation if my boat's working.'

Unfortunately, there were times his boat wasn't working. Like the time his radar failed to pick up a huge ocean liner before it was right on top of his tiny, 36-foot boat. Taking evasive action, he just managed to avoid a collision that would have chopped Intrepid into firewood. Or the time his tiller arm snapped off the coast of Australia during a violent wind storm in the night. There was so much pressure on the mast, Sunderland feared it would break, rendering his boat helpless. 'It was a crazy situation. With all the wind going on, I was in a very vulnerable situation.' But he worked through the night, securing quick fixes as best he could.

His next challenge came as he neared Indonesia. He noticed a small, black, rubber boat speeding toward him. The boat had no business this far out at sea. He adjusted his course to avoid a collision. The boat adjusted with him. He changed direction again. So did the boat. Sunderland knew he was dealing with pirates.

He made his way downstairs and called his father who alerted Australian authorities. They sent patrol planes to monitor the situation, while Sunderland locked his cabin door, grabbed his loaded .357, and hoped for the best. 'It was an hour of hell, with this black boat circling around mine and all over the place,' he says. 'I didn't know what to think. Pirates basically shoot the people on the boats and take anything worth anything and then sink the boats or leave them burnt out.' Sunderland believes the pirates picked up his radio communications with the authorities. They eventually sped away, leaving no trace.

One final hurdle awaited him in the Atlantic. Just as he was nearing Grenada, after more than a month at sea alone, Sunderland was on deck, securing some line. There were no signs of danger, just a building storm on the horizon. He looked to his left just in time to see a wall of green, some 30 feet high, rushing toward his boat. Sailors call them rogue waves. Sunderland called it a disaster. With no time to think, no time to prepare, he clung to the mast, shut his eyes, and waited for the wall of water to slam into him. 'I was tied to the boat, but still, you can get washed off or hit your head, and you're gone. I was holding on for my life.'

He survived, but none of his electronics or communications equipment did. Accustomed to daily contact with his family and team of experts, Sunderland was suddenly more alone than ever before. After a few days, he managed to get a message out to his mom using a preprogrammed text on his SPOT satellite messenger—the communication device still working. 'Hi mom. It's Zac. I'm OK.' Exhausted and shaken, he piloted the broken Intrepid into port for repairs.

On July 16, Zac Sunderland finally pulled into the familiar boat slip at Marina del Rey, Calif. He was tired, exhilarated and eager for a burger.

Among those sending congratulations was another sailor, 17-year-old Mike Perham of Great Britain, then closing in on his own solo circumnavigation started in November 2008. Perham accomplished that goal in August. Sunderland knew his record wouldn't stand forever, and he's mostly grateful for the experience.

What's next for Sunderland? Though he finished enough school work while at sea to graduate from high school, he won't take the predictable path. Instead of college right away, he plans on getting his book published, pursuing a show to highlight his new adventures, or just getting back out in the wild, possibly climbing Mount Everest or exploring the jungles of Africa.

Youngest to sail around the world alone, yes, but Sunderland doesn't think he's all that special. Anyone can achieve his or her goals with the right mindset, he says. 'Go do hard things. If you don't try, it's never going to happen. The majority of people don't even try. You might as well shoot for it with everything you've got, and don't stop when times get tough or it looks impossible. Just keep going. Odds are, something's going to happen.'