An Experimental Study on the Course-changing Manoeuvrability of the KLNG2 Considering Lateral Forces

The application of wind-assisted propulsion systems(WAPS), such as rotor sails and wing sails, has gained increasing attention as an effective solution for reducing fuel consumption and greenhouse gas emissions in the maritime industry. While these systems generate beneficial longitudinal thrust that contributes to ship propulsion, they simultaneously produce unintended lateral force acting on the ship. From a ship manoeuvring perspective, these longitudinal and lateral forces can interfere with the ship’s ability to maintain the desired course and alter the ship's attitude, including the drift angle. These unintended attitude variations can change the hydrodynamic resistance characteristics of the ship, potentially reducing the overall energy-saving benefits of wind-assisted propulsion. Furthermore, externally generated lateral forces may significantly affect ship manoeuvrability, particularly course-keeping characteristics. In this study, free running model tests, including straight-line and zigzag manoeuvre tests, were conducted using the KLNG2 hull form to experimentally investigate the influence of lateral forces associated with wind-assisted propulsion devices on ship manoeuvrability. In addition, a mathematical manoeuvring model capable of representing the effects of external lateral forces was employed to study the influence of the initial attitude on course-changing performance.