Ancient trade in New World may have been carried out using rafts

Washington, March 20 : New findings by MIT researchers has suggested that oceangoing sailing rafts plied the waters of the equatorial Pacific long before Europeans arrived in the Americas, and carried trade goods for thousands of miles all the way from modern-day Chile to western Mexico.

Details of how the ancient trading system worked more than 1,000 years ago were reconstructed largely through the efforts of former MIT undergraduate student Leslie Dewan, working with Professor of Archeology and Ancient Technology Dorothy Hosler, of the Center for Materials Research in Archaeology and Ethnology (CMRAE).

In order to gain a better understanding of the rafts and their possible uses, Dewan and other students in Hosler's class built a small-scale replica of one of the rafts to study its seaworthiness and handling, and they tested it in the Charles River in 2004.

Later, Dewan did a detailed computer analysis of the size, weight and cargo capacity of the rafts to arrive at a better understanding of their use for trade along the Pacific coast.

Although the early sketches give a general sense of the construction, it took careful study with a computerized engineering design program to work out details of dimensions, materials, sail size and configuration, and the arrangement of centerboards.

These boards were used in place of a keel to prevent the craft from being blown to the side, and also provided a steering mechanism by selectively raising and lowering different boards from among two rows of them arranged on each side of the craft.

Although much of the raft design may have seemed familiar to the Europeans, some details were unique, such as masts made from flexible wood so that they could be curved downward to adjust the sails to the strength of the wind, the centerboards used as a steering mechanism, and the use of balsa wood, which is indigenous to Ecuador.

The new work supports earlier evidence documented by Hosler that the two great centers of pre-European civilization in the Americas - the Andes region and Mesoamerica - had been in contact with each other and had longstanding trading relationships.

While Hosler's earlier work had shown a strong likelihood that there had been contact between the Andean and Mexican civilizations, it took the details of this new engineering analysis to establish that maritime trade between the two regions could indeed have taken place using the balsa rafts.

"We showed from an engineering standpoint that this trip was feasible," said Dewan.

According to Hosler, the analysis is "the first paper of its kind" to use modern engineering analysis to determine design parameters and constraints of an ancient watercraft and thus prove the feasibility of a particular kind of ancient trade in the New World.

ANI