The influence of the flow field at the stern due to the operating propeller was investigated experimentally by using a full form ship model. The velocities in front of the propeller and the hull surface pressures with and without a propeller in operation were measured in the towing tank. The potential flow calculation taking into account the propeller-hull inter-action and the 3-dimensional boundary layer calculation were carried out. And, the reliability of the calculation method was examined by comparing it with the results of the measurements. The main results obtained are as follows. (1) The total velocity distribution including the longitudinal vortices was measured in front of the operating propeller. The low pressure region near the bilge part at the stern was hardly affected due to the operating propeller. It was confirmed experimentally that there is a close connection between them. (2) The region of strong velocity gradients in the direction of the propeller radius was influenced more considerably due to the operating propeller than the high wake region. (3) The calculated results of the changes in the hull surface pressure due to the operating propeller explain the measured results fairly well.
