The MMG Model

The MMG model treats the hydrodynamics of the hull, the propeller and the rudder in separate modules. The MMG Standard Method is described in some detail. The equations of motion in the MMG model are derived and the expressions used for the forces and moments due to the hull, the propeller and the rudder as well as the interactions between them are indicated. The MMG equations constitute a complete system for the numerical simulation of most ship manoeuvres. Some specific model experiments are carried out to determine the hydrodynamic derivatives and other parameters in the MMG equations. The linearised equations of motion in the MMG model are used to obtain results similar to those obtained with the Abkowitz model. The Nomoto model is also considered in terms of the MMG equations. Yaw-roll coupling is examined using the MMG model extended to include roll and an example based on linear equations is used to show the effect of such coupling on a ship executing a turning circle.