Mathematical model of the motion of Coast Guard SWATH type

A lot of modern software are used the following methods for the seakeeping of ships calculations: the panel method and the flat sections method. Such calculations are playing an important role for the normal functioning of the designed vessel. For vessels with an atypical contours, panel method is using rather because it shows quite accurate results, but this calculation is carried out for a ship without a speed. But, for the ship motion calculation with speed is more often used Lewis approximation, but in case of small waterline area vessels do not give accurate results, this problem leads to high errors in the final calculation. Compared with other software systems SW52 allows to calculate the frequency-amplitude characteristics at any speed without losing the quality of calculations like in cases of using Lewis approximation. The results of the amplitude-frequency characteristics calculations using the Maccanyo-Landweber approximation in comparison with the results of experimental investigations of the seakeeping of the SWATH vessel “NAVATEK-1” for rolling, pitching and heaving has been performed in the article. However, to apply this complex optimization problem, it is necessary to present it as a standalone block, which is called during the search for the optimum of the goal function. Thus, “SW52” makes calculations based on the spectral theory of motion and allows to calculate the standard deviations of the SWATH vessel’s oscillations within the framework of the correlation theory. That is, the results are formed and agreed to the modern requirements for the seakeeping of patrol vessels according to such parameters as significant rolling, pitching, slamming, and also horizontal and vertical accelerations. The optimization task, which includes calculations of the seakeeping of vessel not only on the calm water, but also on irregular waves, will significantly improve the quality of the results of engineering work at the conceptual design stage for the SWATH vessel.