Imagine the bravery of Asian travelers, thousands of years ago, who set off for the unknown in open canoes called vaka moanas and discovered a new world in the Pacific islands — first New Guinea and the Solomon Islands, then, thousands of years later, Hawaii. They traveled with root crops, fruit seeds and even domestic animals, and they created native communities and what we know as the Polynesian peoples as they went.

Now imagine reproducing those voyages in modern times, aboard the same open boats. That’s some of what Thor Heyerdahl’s legendary voyage of Kon-Tiki in 1947 was all about — proving that major ocean crossings could be done in period craft. Me, I get seasick easily, so I’d rather hurl around a race track at 200 mph than set off on an ocean voyage. But I deeply admire the Pacific Voyager fleet. In seven replicas of the ancient sailing vakas, each carrying a crew of 14 to 16 people from more than a dozen island nations (including Fiji, New Zealand, the Cook Islands, Samoa, Vanuatu, Hawaii and Tonga), they set off from New Zealand in April and arrived in California, where they are now, in early August.

Here's the trailer to "Our Blue Canoe," a film about this epic voyage:

Brynne Eaton-Auva’a, a Samoan raised in Canada, is a crew member on one of the boats, and she’s in San Diego after something like six months at sea. Eaton-Auva’a points out that the voyagers have covered a total of 24,000 nautical miles, all without fossil fuels. That’s enough to circumnavigate the Earth twice. “It’s been a great experience for all of us,” she told me, “though in open boats, when it’s cold, you’re cold, and when it’s wet, you’re wet. Only the sleeping quarters are below the deck.”

The canoes are each equipped with eight solar panels, supplying power to zero-emission electric motors. These days, it’s no longer about proving it can be done. “Our main mission is to spread a message environmental stewardship,” Eaton-Auva’a said. “Because we come from the Pacific Islands, we feel the effects early of climate change and core ocean health. We use the wisdom and techniques of our ancestors, but couple it with technology of today. And we talk about how our ancestors tended to these waters.”

Magnus Danbolt, the Swedish-born head skipper, told me that he got involved as a marine biologist doing work on a documentary about ocean issues. “We want to alert people about oxygen starvation, coral bleaching and steadily rising levels of acidification,” he said. “Because of acidification, phytoplankton — one of the building blocks of life — can’t form shells properly, and that has ripples throughout the food chain. Aquaculture farms growing oysters in the Chesapeake Bay and elsewhere are seeing these same issues in the larvae they raise. The clear effects are already visible.”

On its blog, the group wrote, “During our journey thus far, we’ve seen pockets of floating plastic and debris, litter strewn upon our beaches, and the most heartbreaking: a fin whale just off the shores of San Francisco, struggling in an entangled piece of plastic rope that only took hold deeper.” They also saw blue whales, such as the incredible animal above.

The voyage has not been without incident. Danbolt told me that on their way through French Polynesia, Tahiti and the Marquesas, they went through seven days of 50-knot winds — without losing anybody or any of the boats. But disaster finally struck just a few miles off Point Conception, California when one of the ships lost a mast in high winds.

The crews leave again on Jan. 23 from Baja California for the 10,000-mile return trip, with the goal of reaching the Solomon Islands for a Pacific arts festival by next July. According to Danbolt, one of the great things about the voyage is how it brings disparate Pacific Island communities together, the expatriates who come to meet the crews in California. “That’s very cool to see,” he said.

If you want to help save the oceans, visit with the Blue Frontier Campaign, whose "50 Ways to Save the Ocean" is posted here. David Helvarg, who runs Blue Frontier, told me, "The Pacific Voyagers' flotilla represents a heritage of Polynesian exploration and sustainability. These adventurers are highlighting the wonder of our still-vast seas while also warning of the many ways we're putting our mother ocean at risk. Salute the wonder, heed the warning."

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

'Our Blue Canoe': Pacific islanders cross the ocean in replicas of ancient vessels
The Kon-Tiki proved it was possible to cross the Pacific on a raft. Now Pacific islanders are building replicas of ancient Polynesian sailing canoes and making