In this study, we propose an approach of using Unsteady Reynolds Averaged Navier-Stokes (URANS) coupled with Osaka University (OU) propeller model for KRISO Container Ship (KCS) free maneuvering studies with 6 degrees of freedom (DOF). The advantage of this method is that the hull-propeller-rudder interaction is determined without requiring the detailed modelling of the propeller, thereby reducing computational cost. The model also provides the propeller side and vertical forces which is an added advantage to axisymmetric body force model. Self-propulsion with course keeping, zig-zag maneuvers (±20°/20°) and turning circle (±35°, ±31° and ±30°) were replicated for appended KCS hull in unrestricted waters. The predicted results were validated with the experimental data of various institutions including IIHR and MARIN. Predicted motion and motion rates matched well with the available experimental data for course keeping and zigzag maneuver studies whereas for turning circle, the estimated motion was under-predicted. In addition, the flow field analysis was extended to course keeping and free-running maneuvers, furnishing a qualitative assessment of complex flow mechanism.