Shaft Side Force and Bending Moment on Steerable Thrusters in Off-design Conditions

摘要

The aim of this paper is to investigate the side forces and bending moments on the propeller shaft of thrusters and pods in oblique flow conditions. For this purpose, six components of forces and moments on the propeller shaft were measured for a steerable thruster in different heading angles and advance coefficients, in both pushing and pulling mode in calm water. Tests were also done in waves in order to find the significance of waves on the propeller shaft side force and bending moment components. Some tests were conducted in ventilating condition in some selected cases for comparison with non-ventilating conditions. It is found that the shaft bending moments and side forces are quite large - in the same order of magnitude as the propeller torque and weight. This means that it is important to take the propeller shaft side forces and bending moments into account in the mechanical design of azimuthing thrusters and pods. Also for conventionally shafted propellers, the bending moments from the propeller might be an issue for the stern tube bearing.