The effect of uncoupled propulsion and steering on the manoeuvring behaviour in coastal waters

Abstract The present paper introduces a mathematical model capable of simulating the behaviour of a twin propeller, twin rudder ship in uncoupled conditions, meaning that the portside and starboard propeller and/or rudder work at different rates, respectively angles. Such conditions are typically applied while manoeuvring in harbour conditions. The mathematical model coefficients are determined based on a captive manoeuvring test program which covers these uncoupled conditions. After implementation in the ship manoeuvring simulator, fast-time simulations have been carried out, which were successfully compared with free running tests in uncoupled conditions as well.