Hope Floats – The Kon-Tiki at 66


Postcard image of the famous raft, from the Kon-Tiki museum in Oslo, Norway.

Thor Heyerdahl had a lot of nerve. That’s just what it takes to do what can’t be done.

Sixty-six years ago, on April 28, 1947, Heyerdahl’s five-man crew and a Peruvian parrot named Lorrita set sail from the South American coast at Callao, just north of Lima, Peru. The Kon-Tiki, a balsa wood raft named for an ancient Inca sun god, covered 5,000 miles of ocean in 101 days to land on the Polynesian island of Raroia.


The Kon-Tiki Expedition crew included five Norwegians and one Swede, Bengt Danielsson. Thor Heyerdahl is pictured in the center.

Heyerdahl’s motivation was to support a theory that the South Pacific islands could have been populated, at least in part, by South American people traveling east to west along the prevailing winds and currents. This theory is still contested, however.


Peeling bark after felling a balsa tree deep in the Ecuadorian jungle.


Heyerdahl, 1947, on balsa with bamboo, floating down the Palenque River to the Ecuadorian coast. The wood was towed by steamer south along the coast to Callao, Peru, where it was used to construct the Kon-Tiki raft.

No FPL scientist has worked directly with the Kon-Tiki’s captain or crew but there is a certified portion of the raft on display at the FPL Center for Wood Anatomy Research. The 4x3x1 inch piece of balsa, removed from one of the raft’s large flotation timbers during a restoration project, was sent to FPL in late 2000 from the Kon-Tiki Museum, in Oslo, Norway. It sits among approximately 103,000 other specimens in FPL’s permanent collection, the largest xylarium (i.e., research wood collection) in the world.


Model of the Kon-Tiki with a piece of balsa from the original craft and certificate of authenticity.


The red spot on this model, starboard below the main mast, indicates from where the balsa sample (in background) was taken on the original raft.



In the late 1990s FPL scientists Fredrick (Rick) Green, Alex Wiedenhoeft, and Regis Miller were working to develop a new preservative for balsa. On a whim, Rick Green wrote to the Kon-Tiki Museum to request information about the raft. What he received in return, says Green, was “far more than we asked for.”

The preservation research began in response to environmental restrictions for wood preservatives. Green and colleagues were looking to protect balsa from brown-rot and white-rot decay.

As a result, they developed and patented N’N-Napthaloylhydroxylamine (NHA) as a replacement for heavy metal preservatives such as Chromated Copper Arsenate (CCA), a once-common preservative used in treated lumber.

NHA research continues to this day. Most recently it has been found highly effective against termite infestation. NHA was the primary  insecticide used in the community eradication project centered on a rare northern colony of termites in Endeavor, Wisc. As of 2009, the colony had entirely collapsed.


Building the Kon-Tiki, in a Peruvian naval harbor, 1947. Photo courtesy of the Kon-Tiki Museum, Oslo, Norway.


The Kon-Tiki raft under construction near Callao, Peru.


Certificate of Authenticity