Calculation of transportation and operation indicators of an improved flat raft unit

The implementation of the transportation of wood through the water bodies of the Russian Federation by specialized transport and technological schemes operating on the basis of flat units requires reducing the cost of their manufacture. An improved flat raft unit manufactured in a special bundling machine is considered. A proposed flat raft design features the connection of round timber rows laid perpendicular to each other with flexible links. The extreme logs of the first (lower) and third rows, as well as the second and fourth rows must be fastened with clamps. This allows reducing the cost of manufacturing a flat raft unit with high rigidity, and consequently, the raft wave resistance of the structure. The authors propose a method for calculating the main transport and operational indicators of an improved raft unit that will ensure water logging planning in flat raft units and its safe practicing. They present the calculation of the overall dimensions of the flat raft unit, its wood content volume, stacking factor, buoyancy coefficient, coefficients of draft, wave resistance, stiffness, strength, and floating implements expenditure. Each of these indicators is calculated taking into account the design features of the improved flat raft unit, its external dimensions, the size of the round timber used, floating wood density and all external forces acting on the raft unit during its operation. These indicators allow the initial planning of timber transportation through water bodies and the efficiency of wood rafting is calculated on the basis of an improved flat raft unit. Wood rafting based on the proposed improved flat raft unit with a preliminary calculation of its main transportation and operation indicators according to the presented methodology will make it possible to put small and medium-sized rivers into operation, thereby ensuring the implementation of a full cycle of wood supplies to consumers by water transportation.