Wake fraction and thrust deduction during ship astern manoeuvres

A relatively small amount of data concerning the behaviour of propulsion coefficients, i.e. the wake fraction and thrust deduction at high propeller loading, exist so far. Pioneer works in this field are the model tests by Harvald carried out some time ago. The problem relates in particular to the propeller reversing. The common assumption (and the simplest) is a constant value for both parameters in any manoeuvring regime. How sensitive the simulation of a ship stopping and the steady-state astern movement to these coefficients, will be examined. An identification of wake and thrust deduction is attempted based on full-scale astern manoeuvring trials.