The Governing Equations of Surface Vessels and Aquatic Bodies: Why People Get It Wrong?

Currently, the motion of ships and other surface vessels are described (governed) by certain equations which contain several assumptions. In the same manner, the movement of fish and other aquatic bodies (even submarines) are controlled by another set of governing equations with several assumptions. The chief and common assumption for both situations is that the rotation occurs around the mass centre. This assumption is wrong. The main point, in this analysis, centered around the rotation point of these bodies introduces an error of hundreds if not thousands percent in certain cases. The added properties were neglected in the early studies of these movements up to 198x. Later, the added properties were gradually added to the analysis. In all the cases examined, the analysis assumes that the rotation of these bodies is all the time around the body mass centre. In other words, under this assumption unconstrained ship/fish exposed to a force will rotate around the ship/fish centre. This fundamentally wrong and introduced so large error in many cases into the computation and that probably render the research work worthless. The possible causes of this entrenched assumption are presented. Additionally, the three categories of the of rotation centres are described.This paper describes a breakthrough in the understanding of the governing equations of fish locomotion and also surface vehicles. Very illustrative explanation so that you can understand what is going on