Russian Federation
Of all the known modern types of water transport of the forest, the most promising is timber rafting, which, when used, has both positive and negative properties. Negative indicators include such indicators as: seasonality of work, since use in the winter period is impossible, loss of wood when unloading logs onto water and a raft, large dimensions, complexity of management, the need to unload a raft when unloading it. Passes through non-standard sections of the river bed and subsequent formations, special requirements for the dimensions of the waterway, speed limits and others. One of the most acute problems caused by huge hydrodynamic resistance to movement, which increases with an increase in towing speed, is the limitation of the speed of movement of the raft in the water area. In this regard, the maximum speed of the raft in calm weather reaches no more than 1 1.2 m / s, while two or more powerful tugs are involved. The limited time frame for rafting on wooden rafts is due to the flood period during the spring floods and floods, and they have fallen on hard times. Increasing the raft’s allowable towing speed will shorten the raft’s transport time. A decrease in hydrodynamic resistance when the raft is moving will increase the maximum allowable speed of its towing, which will have a positive effect on the efficiency of timber rafting. Based on the analysis of existing known designs of modern rafts, as well as methods of influencing the reduction of hydrodynamic resistance in the field of shipbuilding, a number of methods have been proposed for reducing the hydrodynamic resistance to the movement of the raft. Methods of reducing the resistance to the movement of the raft by changing the features of its formation by placing separate sections or beams in the streamlined material, the introduction of hydrodynamic fairings are considered. The proposed methods for reducing the hydrodynamic resistance can significantly increase the efficiency of timber rafting.
timber rafting, assortment raft, head hydrodynamic fairing, rafting unit, hydrodynamic resistance, river tug
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