David de Rothschild: Voyage of the Plastiki How to Build a Plastic-Bottle Boat

Text and photographs by Thayer Walker

Once you move past the fact that they both float, two-liter plastic bottles and sailboats share little in common. To David de Rothschild, this is good news. To his boat builder, Mike Rose, it is not. (Read previous dispatches >>)

When de Rothschild began toying with the idea in 2006 of turning a voyage to the Eastern Pacific Garbage Patch into a television documentary, he ran the idea by his buddy, philanthropist and former eBay president Jeff Skoll. Skoll liked the idea, de Rothschild says, but he kept coming back to one concern: where’s the drama?

“‘I mean you’re out there, on a boat, taking trash out of the ocean,’ de Rothschild recalls Skoll saying, ‘and that’s an interesting thing. But where’s the drama?’ I thought that was a good point.”

Which brings us to plastic bottles.

They litter the back end of San Francisco's cavernous Pier 31, HQ for the Plastiki operations. Some are displayed as a wall of art, some sit in a large fish net hanging from the ceiling as future building materials, and some are piled about in their most common incarnation, as trash.

“Bottled water has become a symbol of convenience more than anything,” says de Rothschild. “The best question to ask is, ‘When did we get so thirsty?’”

The bottles, some 20,000 of them, will fill out the catamaran’s twin hulls. De Rothschild sources them from local recycling centers, but he’ll only select 20 percent of the bottles they bring, and the failure rate of those is 20 percent. Before the crumpled discards make the unlikely leap from trash to boat material they must go through laborious refurbishing.

“I think the recycled bottles will perform just as well as new ones,” says Rose, the boat builder, who really has no idea how new plastic bottles would perform on a 11,000-mile trans-Pacific voyage, “but there is a huge cost involved.”

De Rothschild is an aesthetic. He wants only clear bottles, so first they are sorted by color. Then the labels are peeled, the cigarettes removed, and the bottles washed. “There are a lot of cigarettes,” says Rose. “It’s a dirty job.”

Lastly, comes bottle CPR, where crushed and crinkled bottles are brought firmly to life with a scoop full of dry ice.

I ask bottle technician Malin Ulmer to demonstrate the process. She’s reluctant. “I’ve already burned my hands a lot today,” she says while pouring a scoop of dry ice into the crunched bottle.

The ice sublimates into carbon dioxide gas and the bottle expands. A typical car tire requires around 36 pounds per square inch of pressure for proper inflation; the pressure inside this bottle is around 55 pounds per square inch. Sometimes the bottles explode but the team has done strength tests by running them over with a car. It’s all very scientific.

Once the trashed bottles are properly revived, they’re ready to fit into the plywood model of the hull. Two-liter bottles aren’t particularly hydrodynamic and Rose must outfit the bottom of the hull to make sure the bottles all lie flat. Like much of this process, it’s a tedious exercise of trial and error.

“We can’t design the hull with the basics of naval architecture,” says Rose, “we have to design it for bottle alignment.” Hopefully, the Pacific Ocean won’t be able to tell the difference.

David de Rothschild, a National Geographic Emerging Explorer and founder of Adventure Ecology, will depart in Spring 2009 on a 11,000-mile voyage from San Francisco to Sydney (see the route map) in a boat made of plastic bottles. Find out more about the expedition in a feature article by Contributing Editor Paul Kvinta ("Voyage of the Plastiki," October 2008 issue of ADVENTURE). Check in here for updates.