Extension and application of a linearised ship propulsion system model

Abstract The understanding, modelling and analysis of the behaviour of a ship propulsion plant are of great importance for conceptual system design, component selection, selection of control strategy and for propulsion control system tuning. Some of these activities require a relatively simple steady state simulation model, while other activities require a non-linear time domain simulation model which captures the intricacies of the plant, its components and the related controllers. In this paper a linearised model from an earlier publication is taken as a basis for further development. First of all a diesel engine and a hydraulic pitch actuating system are added to the model. Secondly a shaft speed controller is added to the system. Subsequently the controlled propulsion system is verified by scrutinising Bode plots and step responses. After this the linearised model is used to investigate the relation between parameter settings in the engine governor and actual system behaviour in regular waves. This provides the basis for understanding the behaviour of the propulsion system in irregular waves.