Automatic Control and Dynamic Positioning

This chapter explains the basic features of a ship automatic direction control system including proportional, derivative and integral control. The effect of time lag in the system is considered and its effect on the stability of the direction control system analysed. The use of the Nomoto model in ship direction control systems is described. There is a brief review of recent developments in the field. The chapter then describes in some detail the dynamic positioning systems used in ships. The types of ships in which these systems are used, the different modes of operation, the main elements of these systems and their safety requirements are all considered.