USE OF MIRROR PATTERN CUTTING OF netting materials for construction of lake beach seines
Purpose. Justification and calculation of a new methodological approach to the construction of a standard beach seine (502 / 302 х 3.75) with the use of the properties of mirror netting ensuring the saving of the netting material, reduction of weight, price and drag resistance. Methodology. The carp age group selectivity of the constructed seine was assessed within fish fauna monitoring based on the catch analysis of monitoring gill nets with mesh sizes of 30-130 mm according to generally accepted methods [9, 10]. Calculation of netting materials and ropes was carried out according to generally accepted methods [12-14]. Seine resistance was calculated according to N.T. Senin formula for different netting materials and the angles of the movement of different seine parts in water [2]. The gear reliability and data processing were carried out according to standard methods [11, 14, 15]. Findings. A variant of the construction of the maximum lightweight beach lake seines made of mirror pattern netting taking into account the properties of the mirror pattern netting material, reduction of weight, price and drag resistance has been proposed. The provided recalculation of the properties of a serial seine made of rhombic mesh for the mirror netting seine taking into account netting properties allowed: 1) reducing the seine drag resistance value by 1,4 times; 2) reducing the weight of netting materials by 16.3% compared to the prototype; 3) increasing the seine selectivity when fishing older age groups of carp in non-drainable ponds. Originality. We presented the method of the calculation and construction of lake beach seines made of mirror netting, analyzed the technological stages of the construction of mirror netting, determined main qualitative and technological parameters, which had effect on the conditions of the construction and reliability of such fishing gears. A new method of the use of an insert of the combined netting material cutting ensuring higher output of the finished product was proposed. Practical value. Implementation of the proposed fishing gears with higher catchability and lower cost of the fishing harvest process in non-drainable ponds can contribute to an increase of the economical efficiency of these fish farms. The proposed method of the mirror netting construction can be used for serial manufacture of fishing gears and for production of the netting material with mirror mesh at a net manufacture facility.