Floating a Big Idea:
MIT Demos Ancient use of Rafts to Transport Goods
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 shipwormshow 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. After construction, those replicas were allowed to sit near shore for weeks before the test voyages. "That's where the shipworms live," Dewan said. "One way to avoid that is to minimize the amount of time spent in harbor." Dewan and Hosler did a simulation of the amount of time it would take for shipworms to eat one of the rafts and concluded that with proper precautions, it would be possible to make two round-trip voyages from Peru to western Mexico before the raft would need replacing. 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," Dewan said. Her analysis showed that the ancient rafts likely had a cargo capacity of 10 to 30 tons-about the same capacity as the barges on the Erie canal that were once a mainstay of trade in the northeastern United States. Hosler said 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. And for Dewan, it was an exciting
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departure from her primary academic work. "I just loved working on this project," she said, "being able to apply the mechanical engineering principles I've learned to a project like this, that seems pretty far outside the scope" of her work in nuclear engineering.
2009 - 2010 VESSEL LEASE FOR PORT TOWNSEND - KEYSTONE FERRY ROUTE REQUEST FOR EXPRESSIONS OF INTEREST
The Washington State Department of Transportation, Ferries Division, operator of Washington State Ferries (hereinafter called "WSF") is seeking expressions of interest for the following project: A lease of one (1) auto ferry for service on the Port Townsend - Keystone ferry route in Puget Sound, Washington. The lease will be for an interim period of time while WSF contracts for the construction of new auto ferries to operate on that route. The requested lease is for eight (8) months, from August 2009 through March 2010, with a possible earlier commencement date depending on vessel availability. The vessel will be operated by WSF crews, approximately sixteen (16) hours per day, seven (7) days per week. The route service distance is approximately 4.3 nautical miles each way. The vessel must have the following minimum characteristics: � Minimum of 300 passengers and 50 vehicles; � Double ended vehicle loading and offloading (no side loading capability); � Minimum service speed of 11.5 to 12.0 knots @ 85% maximum continuous rating of engine output; � USCG certified for Lakes, Bays, and Sounds with a current Certificate of Inspection; � Minimum two compartment subdivision; � Sea Keeping capability for operating in 4 to 6 feet sea conditions without water on deck; � Capable of carrying vehicles of 80,000 to 100,000 lb weight; � Clear vehicle deck height for tall vehicles - minimum 14 feet; � Maneuvering stopping distance from full speed to full stop within two boat lengths; � Double ended propulsion; no backing into or out of Keystone Terminal; � Maximum draft 13.0 feet; � Meets ADA accessibility requirements for passenger areas and restrooms; and � Meets USCG 100% life raft capability. Subject to the above requirements, interested vessel owners should send a description of their vessels as soon as possible to the address listed below. The responses are non-binding as to vessel availability. Director of Legal Services & Contracts Washington State Ferries 2901 Third Ave., Ste. 500 Seattle, WA 98121-3014 Phone: 206-515-3601 � Fax: 360-515-3605
WSF assumes no obligation of any kind for expenses incurred by a respondent to this Notice.
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