CALCULATION OF THE VESSEL’S ROTATION CENTER DISPLACEMENT
https://doi.org/10.33815/2313-4763.2023.1-2.26-27.044-055
Abstract
A simple deflection of the rudder leads to the appearance of the angular rate of the vessel rotation around the rotation center and at the same time the lateral speed of movement of the rotation center. Such a complex movement of the vessel is difficult for the shipmaster to understand and make the right decision. At the same time, lateral and rotational movements can be replaced by one "pure" rotation of the vessel around another point - the pivot point. Knowing the position of the rotation center and the pivot point position allows us to reduce the maneuvering area of the vessel, which is especially important when maneuvering in compressed waters. The purpose of the work is to determine the rotation center displacement relative to the center of gravity/middle of the frame at the maximum speed of the vessel's circulation. This aim is achieved by comparing the position of the pivot point on a stationary vessel, determined theoretically, and the position of the pivot point on a vessel circulating at maximum speed, determined during an experiment on a navigation simulator Navi Trainer 5000. Since the position of the pivot point depends only on the relative arm (between the steering wheel and the center of gravity/middle frame) of the lateral force application, which is the same in both cases, the detected difference will be the displacement of the center of rotation. The results of the conducted experiments and performed calculations show that the position of the pivot point, calculated for a stationary vessel, differs from the position of the pivot point of a vessel circulating at maximum speed by an amount of ∆Х = (0,14 – 0,2). According to the authors, the detected difference is explained by the displacement of the ship's center of rotation relative to the center of gravity/middle frame in the presence of longitudinal speed. The theoretical significance of the obtained results consists in experimentally proving the effect of the displacement of the pivot point and establishing the cause - the displacement of the center of rotation, depending on the speed of the vessel. The practical value of the obtained results is to use the effect of the displacement of the center of rotation to reduce the maneuvering area, which is especially important in compressed waters.
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