Polynesian navigation snow. In the mid-20th century, Thor Heyerdahl proposed a new theory of Polynesian origins (one which did not win general acceptance), arguing that the Polynesians had migrated from South America on balsa-log boats. The presence in the Cook Islands of sweet potato that is a plant native to the Americas (called "kūmara" in Māori), which have been radiocarbon-dated to 1000 CE, has been cited as evidence that Americans could have traveled to Oceania. The current thinking is that sweet potato was brought to central Polynesia circa 700 CE and spread across Polynesia from there, possibly by Polynesians who had traveled
Herman Watzinger which was cancelled because of World War II, and applied for a job in the U.S and sought a visa to the U.S. He met Thor Heyerdahl in New York City, where he was asked to participate in the construction of the Kon-Tiki raft and become a member of the expedition. On board the raft, where he was second in command, he was responsible for meteorological and hydrographic measurements. After the Kon-Tiki expedition, he returned to Lima in 1970, where he worked as head of fisheries, projects and advisor in freezing techniques for WR Grace & Co and Atlas. Watzinger