Hydrodynamic Characterisation and Structural Design Analyses of an Airboat

摘要

This paper presents the structural design and hydromechanics performance characterization of a prototype airboat of length= 2.42m, beam= 1.11m, draught= 0.32m, and powering =30 kW. Modified Savitsky’s model and test-data are utilized for the analysis. The results show that the hull-trim increases from static trim to a peak value of 5.2° at Fn =2.50 in the non-planing speed regime; and then decreases to a plateau in the planing-speed regime. This phenomenon is explained by the aftward drift of the point of action of the resultant lift force towards the centre of gravity. For higher Froude number, bottom-velocity ratio increases towards unity: i.e. a reduced wake effect. Resistance curve for airboat is “Ogive” shape, rather than parabolic; whereas the effective power is parabolic. Correlation of analysis and test data shows a good agreement, except at transition speed. Therefore, the analysis is valid for characterizing airboats parameters.