Simulation of turning maneuver using the 4+2DOF method in planing and semi-planing modes

Abstract

Planing craft maneuver is dominated by attitude change which requires a 6DOF motion equations. Recently, 4+2DOF method as a kind of the 6DOF motion equations was introduced in which heave and pitch motion are replaced by rise-up and dynamic trim. The 4+2DOF method was employed for the turning maneuver that start and end in the planing mode. In this study, the application of 4+2DOF method is extended to examine a turning maneuver that starts in the planing mode and ends in the semi-planing mode. Simulations are conducted on a model which has already been tested in full-scale maneuver trials. Maneuver Hydrodynamic Coefficients (MHCs) are concluded from Plannar Motion Mechanism (PMM) tests in both the planing and semi-planing modes in a range of forward speeds. Having a verified computer code, effects of operation modes and forward speed are studied on the turning maneuver. This study quantitatively depicts that the Steady Turning Diameter (STD) in the planing mode is about four times larger than the semi-planing mode. It is also concluded that STD of a turning maneuver starts and ends in the planing mode, is about 2.5 times larger than that starts in the planing mode and ends in the semi-planing mode.