No abstract

One of the aims of the Colombian Ministry of Defense in the field of science and technology is to develop and build in-house simulators for training. An important prerequisite in the development of these types of simulators is to have accurate knowledge about the forces that act on the particular type of ship being considered. In the pursuit of this objective, the Science & Technology Corporation for the Development of the Shipbuilding Industry in Colombia — COTECMAR has established a research program for the development of physics-based models to predict the generalized forces acting on maneuvering ships. The following article proposes a mathematical model capable of providing the simulator with calculations for the hydrodynamic forces acting on three types of ships: displacement ships, submarines and planning hulls. Derived from slender-body theory (SBT), the mathematical model presented minimizes computational time and eliminates the need for experimental data, making it possible to use the calculation of hydrodynamics forces at the initial stages of design when the geometry of the ship is constantly revised and the effect of those changes in the dynamic performance of the ship needs to be assessed. The article explains the mathematical model proposed and its modular nature, compares existing numerical and experimental data with results obtained from this study for the three case studies selected: displacement ships, submarines and planing hulls.

Information regarding a turning ship's pivot point has been collected, taking practical notes and ship maneuvering manuals into account as well as experimental data and simulated results, together revealing consistent behaviour when varying water depth or some ship's particulars. Results from studies already carried out using the Colombian Navy's River Support Patrol Vessel (RSPV) are included here to estimate the pivot point and contrast results with theory and available observations. Linear manoeuvrability theory was tested and the results revealed poor agreement with kinematic equations. As to the depth variation effect, full-scale experiments confirmed that the pivot point's position, when in shallow water, always varied in the same way, thereby agreeing with available pivot point information.