Experiment of the first bamboo raft, IRA 1.

A bamboo raft designed to evoke prehistoric craft was too heavy and unwieldy for its crew to control during a test voyage off the coast of Taiwan. Credit: Yousuke Kaifu/Antiquity Publications Ltd

Archaeology

On a model ancient raft, seafarers are up the current without a paddle

A bamboo craft built to resemble prehistoric boats proves unfit for a sea voyage.

A failed voyage in a replica of a Stone Age boat shows that Asian mariners had better watercraft than once thought, archaeologists suggest.

Signs of human occupation across the islands of southeast Asia and Australia suggest that Homo sapiens embarked on long-distance sea crossings before 47,000 years ago. Researchers had assumed that these voyages were made on crude bamboo rafts. A team led by Yousuke Kaifu, at the National Museum of Nature and Science in Tokyo, Japan, tested this theory by building a 10.5-metre-long bamboo raft with the help of stone tools.

On 11 June 2017, a crew of 5 professional and near-professional kayakers attempted to sail the craft from Taiwan to cross the strong Kuroshio ocean current, which must have been traversed by Palaeolithic voyagers who settled the Ryukyu island chain roughly 30,000 years ago. After paddling 80 kilometres in 14 hours, the kayakers abandoned the journey because of strong ocean currents and damage to the raft.

Prehistoric humans must have made such voyages in sturdier boats, say the researchers, who succeeded in making the crossing in 2019 in a boat carved from a large log.