From
Wikipedia:
Heyerdahl and a small team went to Peru, where they used trees and other native materials to construct a balsawood raft in an indigenous style (as recorded in illustrations by Spanish conquistadores). Accompanied by five companions, Heyerdahl sailed it for 101 days over 4,300 miles across the Pacific Ocean before smashing into the reef at Raroia in the Tuamotu Islands on August 7, 1947. The only modern equipment they had was a radio.