Hydrodynamic interaction effects on tugs operating within the midship region alongside large ships

This paper presents the findings of a numerical and experimental study to investigate the interaction effects induced on a tug operating within the midship region of a large ship at varying drift angles and lateral distances between the vessels. The non-dimensional interaction forces and moment coefficients determined for the tug are used to create a novel Hydrodynamic Interaction Region Plot (HIRP) to identify the variation of these coefficients with respect to the tug’s drift angle and relative lateral distance to the larger ship. The results identify the drift angle range for the tug required for a safe approach towards the midship of the larger ship, ensuring the least interaction induced lateral force and yaw moment in order to minimise collision risk.