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.
Dewan also analyzed the materials used for the construction, including the lightweight balsa wood used for the hull. Besides having to study the aerodynamics and hydrodynamics of the craft and the properties of the wood, cloth and rope used for the rafts and their rigging, she also ended up delving into some biology. It turns out that one crucial question in determining the longevity of such rafts had to do with shipworms-how quickly and under what conditions would they devour the rafts? And were shipworms always present along that Pacific coast, or were they introduced by the European explorers?
Shipworms are molluscs that can be the width of a quarter and a yard long. Because balsa wood is so soft, and doesn't have silicates in it like most wood, they are able to just devour it very quickly, Dewan said. It turns into something like cottage cheese in a short time.
That may be why earlier attempts to replicate the ancient rafts had failed, Dewan said. Afte
|Contact: Elizabeth Thomson|
Massachusetts Institute of Technology