Sunderland left the docks at Marina del Rey aboard his 11-metre yacht the Intrepid on June 14. His first port of call will be the Marshall Islands in Micronesia, 4,000 miles away. His dad will greet him there and at other strategic destinations to offer moral support. “I know that this is dangerous,” Zac admitted in a recent interview. “But life is dangerous. I feel everything in my life thus far has been leading to this decision. I’m 100 percent sure that I’ll be able to do this.”

Others are not so confident. Six-time world sailing champion Derrick Fries told ABCNEWS.com that he would not attempt it. “There will be times when it’s absolutely ecstasy, and it will be sunny and the ocean will be calm. That will be great, but it may be only seven percet of the time. It’s a highly risky endeavour,” said Fries, who feels the chances of Zac not experiencing mechanical failures is extremely unlikely.

Sunderland, a six-foot, 165-pound athlete, who starred as a linebacker on high school football team, is the oldest of Marianne and Laurence Sunderland’s seven children. A lifelong sailor, he was actually born aboard a 17-metre sailboat. His father, a shipwright and yachtsman who for years raised his family on boats, said about his son’s trip: “When Zac came to me with this idea I thought it was a great plan. In fact, I think it’s fantastic when a kid decides to undertake such a noble cause. Better yet, it is something that I have been able to help him with.”

By help he means a complete overhaul of the boat–which Zac bought in January for $6,500–strengthening the keel, bulkheads and the mast, replacing standing and running rigging, adding a computer for e-mail, an auto pilot, two proximity radars to warn of approaching ships, solar panels, a windmill generator and a new engine that will be used only when approaching ports. Zac will be able to e-mail and blog on his website: (zacsunderland.com.) and he’ll also have a satellite phone enabling free calls and access to detailed weather reports from anywhere.

The teenager’s diet will include freeze-dried food, vitamins, malaria pills and other medications. He has fishing gear so he can supplement his meals with fresh meat. His bed is a narrow bunk that he’ll strap himself into each night, so he doesn’t roll off. When an alarm sounds, it’ll either be time to wake up and resume sailing, or evade large ships. There’s also a system where all 12 lines and four hand-winches can be worked from the relative shelter of the cockpit.

The home-schooled A-student claims he was inspired by the swashbuckling escapades of other young adventurers such as American Robin Lee Graham, who wrote a book called Dove about his circumnavigation of the globe which began at age 16 in 1965, and finally ended in 1970 when he was 20; and Aussie Jesse Martin, whose book Lionheart: A Journey of the Human Spirit, was based on his non-stop solo circumnavigation of the world, which he completed in 1999 at age 18.

True to his serious nature, Sunderland has taken all his textbooks with him. “I have one more year to finish at high school and I have to send back my tests [via e-mail] to my mum. She’s going to grade them and make sure I am doing well.” Zac plans to write a book and record videos to document his 40,000-mile voyage.

Sunderland’s route will take him west across the Pacific to the Solomon Islands, Papua New Guinea, Australia, the Indian Ocean, Mauritius and Madagascar, then around the Cape of Good Hope off South Africa. Sunderland expects this section will be the most challenging of the trip. Also referred to as the Cape of Storms, the waters here are tumultuous and unpredictable. In fact, Sunderland considered sailing through the Suez Canal to avoid rounding the Cape, but recent incidents involving pirates off Somalia, which must be passed to enter the Red Sea, prompted him to plot a course around rather than through Africa.

His father believes that a greater challenge for his son will be overcoming fatigue caused by sleep deprivation, which Zac is bound to encounter, as he’ll be able to nap only during fair weather. “That kind of fatigue can make even the simplest task impossible,” said Laurence. “But the beauty is that Zac is familiar with that, because he has been sailing all his life.”

After rounding the Cape of Good Hope, Sunderland will sail across the Atlantic, pass through the Panama Canal, then visit the Galapagos Islands before setting a northward course home. If he makes it, and that remains a very big if, the odds are he will come back much older than his years.

Despite the risks, the majority of their experiences in the Muslim world were very positive. They were especially moved by the hospitality and generosity of the people they met. “The media gives you the impression that everyone in these places hates Westerners,” says Thrower. “We found that wasn’t true. It was unbelievable how open and friendly people were.” Thrower believes that their mode of travel encourages personal contact. “People can approach us easily and the sight of the bikes draws attention.”

In Yemen, the sight of the two Canucks in their helmets and leathers was such a novelty that it was routine for them to be surrounded by 20 to 30 people, all smiling and laughing and reaching out to touch them and their gear. “It’s not the personal space we’re used to in North America,” admits Thrower. “Over there, it’s about five millimetres.” These encounters were made even more disconcerting by the fact that virtually every Yemeni male they met carried an AK-47 assault rifle and a nasty looking dagger.

But this is exactly the sort of intense, visceral experience that these two road warriors seek. Culture shock, surprise and adversity are all part of the kick. Their itinerary is typically characterized by strenuous outdoor activities, UNESCO World Heritage sites, experimentation and a willingness to get sidetracked and lost. Bars and nightlife are not part of the menu, nor are expensive hotels. They travel as cheaply as they can, camping whenever possible and carrying a stove to cook their own food. The cost of their six-month expedition in 2006, including food, accommodations, fuel and maintenance came to $18,000.

Today, Thrower and Altmann are in the midst of an even more extreme undertaking–a 12-month, 60,000-kilometre trek around Africa. The highlights to date include visiting the mountain oasis of Tamerza in Tunisia, the tombs of Jebel Barkal in the Sudan, the rock-hewn churches of Lalibela in Ethiopia and climbing Tanzania’s Mt. Kilimanjaro. But they still have six more months of travel ahead. Like all of their journeys, this one is meticulously documented on their web site, www.2canadiansonbikes.com, which features an impressive array of photographs.

In the future, Thrower and Altmann plan to tour Russia and Asia in 2009-10, Australia and New Zealand in 2010-11 and Central and South America in 2011-12. After that, they may even give up their precious motorbikes and buy a boat and sail the world. “Our goal is to keep on exploring and finding other ways to travel,” says Altmann, who finds inspiration in Helen Keller’s famous quote: “Life is either a daring adventure, or nothing.”