Vessel Thruster-Thruster Interactions During Azimuthing Operations

Flow interaction between thrusters is important, as many offshore vessels are equipped with rotating (azimuthing) thrusters for ease of manoeuvring and dynamic positioning. Accurate prediction of available thrust to resist horizontal environmental forces is essential allowing the realistic station-keeping capability of these vessels to be established. Additionally such thrusters are in many cases used, possibly in conjunction with tunnel thrusters and main propeller to provide propulsive power in transit. This paper presents the influence of two thrusters in close proximity, azimuthing so that flow into one thruster is influenced by the flow through the second thruster. The work extends that previously presented in OMAE 2002, based on a comprehensive experimental study to establish the influence on thruster performance of variations in current inflow velocity, thruster power, and thruster position relative to the hull.