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H Y D R O P E D . H Y D R O F O I L
Courtesy of Sid Shutt
Designed and built by Sid Shutt, the hull of this boat is constructed of wood, fiberglass and foam. It weighs only 35 pounds. The propeller is constructed in a mold using carbon fiber and the foils have a layer of fiberglass over wood. The overall gear ratio is 2:1. Its record speed is 17.78 mph/15.45 knots.
The principal of Shutt's propeller design is to limit the "slip" around the propeller blade. The propeller of the Hydroped has a measured efficiency of over 90%. By contrast, a power boat propeller has an efficiency of 85% and an Olympic type rowing shell has a propulsion efficiency of only 66%.
The system used to control the height that the Hydroped "flies" above the water is located at the bow. It consists of a forward float that is connected to the front wing. If the nose is too low, more lift is applied to the front wing and if it is to high, less lift is applied and the nose is allowed to "sink". By placing the surface sensor ahead of the front wing, the system can better react to approaching waves. This system, created by Shutt, is used by all of the more successful hydrofoils. Having the large wing in back, and the control surfaces in front is called a "Canard" design, and is much easier to control.