June 20, 2008 -- Zac Sunderland is no ordinary 16-year-old boy. While his friends play video games and go on their first dates, the high school sophomore is traveling around the world -- on a sailboat, no less.
"I'm 100 percent sure that I'll be able to do this," Zac told ABCNEWS.com of his yearlong trip that began on June 14, which he hopes will make him the youngest solo American sailor to circumnavigate the world.
"It's going to be an amazing adventure," Zac told "Good Morning America." "Life changes you as you move along through it."
But so far, Zac's amazing adventure is taking him for a ride. One recent entry in his online blog points to exhaustion.
"I've been feeling anxious about the situation and about the boat," Zac wrote. "I'm tired and I'm tired of rocking around going nowhere. The weather should go back to normal by the end of the week, but that seems unbearable at the moment!!"
"I can hear in his voice that he's really tired," said his mother, Marianne Sunderland, who recently spoke to Zac via satellite phone. "The name of the sailing game is patience. ... We've just been encouraging him that that's part of the whole thing."
Zac is a veteran of the seas despite his young age. He was basically raised on a boat -- Zac's first home was his parents' 55-foot yacht -- and he sailed for the first time at just 6 weeks old. His father is a master shipwright near their home in Thousand Oaks, Calif.
Sunderland told ABCNEWS.com that she's not worried about her son's safety.
"I know that he'll have rough times, but I'm not worried because the boat is in good shape and he's got a lot of good equipment, a lot of experience and a lot of support," Sunderland said.
"The end result is that he's going to experience a huge range of emotion and experience and struggles and successes that are going to make him into an incredible man," said Sunderland on "Good Morning America."
The dangers of Zac's trip are numerous. Circling the globe is an ordeal of at least 21,000 miles that has cost some intreprid sailors their lives. There are sudden storms, waves of 20 feet to 60 feet, even pirates to contend with. Cape Horn, the route around South America, has some of the world's most treacherous waters.
Then there's the thousands of hours of isolation, coupled with sleep deprivation during stormy seas when the boat must be constantly tended, which can have profound psychological effects on some people. Collisions with submerged objects and the danger of being swept overboard are constant perils.
All this is leading some to ask whether the Sunderland's are letting their son take too big a risk.
How Young Is Too Young to Risk It All?
Teenagers often don't yet have the brain power to weigh the consequences of big decisions such as Sunderland's, Dr. Elisabeth Guthrie, a pediatrician and psychiatrist at New York's Columbia University told ABCNEWS.com.
"Teenagers are still in the midst of a dynamic period in their brain development, and their ability to make decisions," said Guthrie, who has not treated Sunderland. "In general, teenagers are nowhere near as mature in their decision-making abilities as adults."
"Teenagers do, in general, believe that they're much more immortal than they actually are, so they're not necessarily good at assessing how a particular risk may pertain to them."
When asked if he's thought about the potential for death on his journey, Zac told ABCNEWS.com that he tries not to.
"I don't think about it too much because you just can't," he said. "And I have all the survival gear."
In addition to the typical life vest and dingy, Zac's 36-foot Islander sailboat -- which he bought with $6,500 he'd saved during his childhood -- is equipped with state of the art technology, including a satellite phone, radars and GPS systems.
Still, even with all the gear, many experienced sailors are daunted by the prospect of such a trip.
Six-time world sailing champion Derrick Fries told ABCNEWS.com that even he wouldn't attempt it.
"There will be times when it's absolutely ecstasy, and it will be sunny and the ocean will be calm," said Fries. "That will be great but it may only be 7 percent of the time."
"It's a highly risky endeavor, I wouldn't do it," said Fries, who said the chance of Zac not experiencing mechanical failures is extremely unlikely.
Before even setting sail, Zac ran into some difficulty and had to postpone his departure by two weeks. The engine failed and needed replacing, he said.
Risks Are Part of Life, Some Say
While many parents would never let their child sail off into the sunset alone, some parenting experts told ABCNEWS.com that taking risks is part of growing up.
"When calculating a risk, it's important to take into account who you are and what you know," said parenting expert and founder of Teenfrontier.com Barbara McRae. "He's been a sailor since childhood and was essentially born on a boat."
"I'd say Zac is ready to live his dream," said McRae, who added that the same answer would not apply to all risk-taking kids, and depends entirely on the individual child's experience.
"If it were a situation where somebody was not prepared and was not passionate I'd say absolutely not," she said. "I don't think the [Sunderland parents] are being bad parents -- they're supporting their son with his dreams and not allowing their fear to get in the way of that."
The Sunderlands are not the first parents to let their children take such journey. At age 18, Australian Jesse Martin, a good friend of Sunderland's, made a solo-trip around the world.
In 1965, American sailor Robin Lee Graham became the youngest to boat across the world when he sailed into his final port at 20 years old.
Zac said it was Graham's successful adventure -- and a book of photographs published about it -- that inspired him to try it himself. He plans to keep his blog updated and film a documentary during his trip. He is also bringing his school books along and plans to study on the way.
And for Marianne Sunderland, letting herself or her son live a life controlled by fear is simply not an option, no matter what her critics may argue.
"There are risks, but we look straight at them and minimize them and feel that it's not negligent by any means," said Sunderland. "I obviously don't want him to die, but I would not have any second doubt."
"If [he died] it would be devastating, but you can't live life ruled by fear," she said.