Evaluation of Mathematical Models for Tankers’ Maneuvering Motions

In this study, the maneuvering performance of two tanker ships, KVLCC1 and KVLCC2 which have different stern forms are predicted using a system-based method. Two different 3 DOF (degrees of freedom) mathematical models based on the MMG(Maneuvering Modeling Group) concept areappliedwith the difference in representing lateral force and yawing moment by second and third order polynomials respectively. Hydrodynamic coefficients and related parameters used in the mathematical models of the same scale models of KVLCC1 and KVLCC2 ships are estimated by using experimental data of NMRI (National Maritime Research Institute). The simulations of turning circle with rudder angle ±35o , zigzag(±10o /±10o ) and zigzag (±20o /±20o ) maneuvers are carried out and compared with free running model test data of MARIN (Maritime Research Institute Netherlands) in this study. As a result of the analysis, it can be summarised that MMG model based on the third order polynomial is superior to the one based on the second order polynomial in view of estimation accuracy of lateral hull force and yawing moment.