RESISTANCE AND EHP OF A 'FOIL-MARAN' CONFIGURATION AS PREDICTED FROM SMOOTH WATER TESTS OF MODEL 4836-3.
Research and development rept.,
DAVID TAYLOR MODEL BASIN WASHINGTON D C HYDROMECHANICS LAB
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A model of a catamaran planing boat was equipped with a diamond-shaped surface-piercing hydrofoil to eliminate instabilities encountered with an earlier foil configuration TMB Report 1852. The hydrofoil configuration was located forward of the center of gravity, and two high deadrise planing surfaces integral with the hull were located aft of the center of gravity. Smooth water resistance tests were made with various LCG locations and with the foils at various angles of attack and various fore and aft positions, to determine an optimum configuration. Model speed, resistance, trim, and wetted length were measured throughout the speed range for a number of foil positions, foil angles, and hull trims. The best condition from a stability and resistance standpoint was then expanded to full scale. The results for the optimum configuration are presented in dimensionless form and also in the form of trim and ehp versus full-scale speed in knots. Rdelta comparisons are also made for the foil-maran, the parent catamaran hull, and a conventional planing hull. At high speed the resistance of the foil-maran was less than that of the catamaran. However, the resistance of the foil-maran was considerably greater than that of the conventional planing hull at all speeds. Author
- Marine Engineering
- Fluid Mechanics