Experiments with a model of a boat and catamaran in the experimental pool of KSTU to study the small fishing vessels thrust to determine the towing trawl structures conditions

Small-sized vessels are an integral part of the commercial fleet of the Russian Federation, they are engaged in catching hydrobionts inhabiting the coastal zone, as well as in lakes and reservoirs, where it is possible to conduct trawl fishing operations. At the moment there is a problem with the choice of fishing gear, because during the design they cannot determine the exact and close to the real thrust of the vessel. When calculating the draught, methods suitable for medium-sized, large-capacity vessels are used and the results for small vessels are only estimates. The most proven method to determine the thrust is by experience, but this method is difficult from the point of view of economics, so the simpler option is to conduct similar tests with a small version of the original fishing vessel and use computer technology to determine the necessary data. Conducting experiments with a model of a fishing vessel is an economical solution, but requires high knowledge in modeling the thrust characteristics of the vessel. The authors of the article have the necessary competence to conduct such studies and can determine the real thrust of fishing vessels with an insignificant error. So, the authors experimentally investigated the thrust of the boat model Syma Q1 Speedboat RTR 2.4G SYMA-Q1 and a catamaran consisting of similar boats. This work takes into account the vessel – fishing gear relationship and determines the thrust characteristics, which include directly the thrust of the fishing vessel and the various resistances of its elements (hull, propeller, etc.), which affect the final value of thrust. In trawl fishing, hydrodynamic resistance of the trawl structure elements arises, which must be compared with the thrust of the fishing vessel. According to the obtained experimental data the dependencies for vessels were constructed, and also the developed computer program for the computer “Hydrodynamics of the vessel” was used. Thanks to this program, the calculation and analysis of water pressure on the object is performed, and also it becomes visually understandable in which parts of the pressure has a large force