Improvement of mechanized kelp extraction tools, taking into account design and environmental constraints

The paper examines the design and technological characteristics of existing mechanized harvesting equipment for kelp (Saccharina latissima) used in the Northern and Far Eastern fishery basins of the Russian Federation. The operational efficiency and environmental limitations of seaweed mowers, dredges, and semi-rigid bottom harvesters are analyzed. The study aimed to substantiate engineering approaches for improving mechanized harvesting equipment while increasing harvesting efficiency and reducing adverse impacts on benthic ecosystems. The research was based on the analysis of existing harvesting technologies, regulatory requirements, published scientific data, and engineering calculations. Calculations were performed for the submerged weight of harvesting devices, specific bottom pressure, hydrodynamic resistance, and the kinematic parameters of the cutting mechanism. The results demonstrated that the principal factors limiting harvesting efficiency are excessive pressure on the seabed, unstable operation of cutting mechanisms, clogging of cutting elements with harvested algae, and substantial biomass losses. The application of positive buoyancy elements combined with wire-rope position control was shown to reduce the effective bottom pressure to 3.95-10 kPa, thereby minimizing damage to benthic habitats. The optimum cutting speed was determined to be 2.5-3.5 m/s, ensuring efficient stipe cutting with minimal raw material losses. Engineering solutions for the modernization of seaweed mowers and semi-rigid bottom harvesters are proposed, including mechanically driven cutting mechanisms, segmented support elements, underwater video monitoring, echo sounding, and an integrated vacuum pumping system. The proposed modifications improve operational stability, provide a more continuous harvesting process, reduce biomass losses and mechanical loads on the equipment, and significantly decrease the environmental impact on benthic ecosystems. The obtained results can be applied in the development of advanced mechanized kelp harvesting systems and in improving commercial harvesting technologies for the Northern and Far Eastern fishery basins.