• Ocean and Polar Research
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• v.23 no.3
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• pp.305-310
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• 2001

This paper describes a floating fish reef technology for enhancement of fisheries productivity in the muddy areas. The floating fish reef was composed of main fish cage, anchor rope and concrete anchor blocks. Main fish cage was made up of 12 steel buoys measuring 0.37m in diameter and 1.5m long, polyethylene (PE) netting and circular steel rings. Each steel buoy had buoyancy of 110kgf. The size of main fish cage was 1.96 m in diameter and 3.75m in length. Monitoring on its durability was made for eight months after installation. The steel buoys fixed on main fish cage and nettings were observed to be kept safely. The wet weight of fouling organisms per unit area$(m^2)$ was 26.6kgf after eight months. Reduction in the cross-section of steel buoys and circular steel rings of main fish cage were not found. In addition, any cracks on the concrete anchor blocks were not observed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.1
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• pp.20-31
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• 2010

In this research, the submersible fish cage was designed to avoid structural and biological damage during harsh sea conditions. The submersible cage system consists of netting, mooring ropes, a floating collar, floats, sinkers and anchors. Whole elements of the cage were modeled on the mass-spring model. The computer simulations were carried out to investigate the dynamic behavior of the cage and to calculate mooring line tension subjected to tidal currents and waves. As expected, the tension values in the mooring line of the submerged position are 36% less compared to that of the surface cage under the same loading conditions. As the wave was used in combination with the current velocity of 1m/s, the average tensile load for the submerged cage showed 85% of the value for the floating cage. The simulation results provide an improved understanding of the behaviors of the structure and valuable information on the optimized design of the cage system exposed to open ocean environmental factors.

• Wind and Structures
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• v.36 no.1
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• pp.31-40
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• 2023

This paper investigates the mechanical behavior of full-scale offshore fish cages under hydrodynamic loads. To simulate different cases, different materials were used in the fish cage and analyzed under different flow velocities. The cage system is studied in two parts: net cage and floating collar. Analyses were performed with the ANSYS Workbench program, which allows the Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) method to be used together. Firstly, the fish cage was designed, and adjusted for FSI: Fluid (Fluent) analysis. Secondly, mesh structures were created, and hydrodynamic loads acting on the cage elements were calculated. Finally, the hydrodynamic loads were transferred to the mechanical model and applied as a pressure on the geometry. In this study, the equivalent (von Mises) stress, equivalent strain, and total deformation values of cage elements under hydrodynamic loads were investigated. The data obtained from the analyses were presented as figures and tables. As a result, it has been shown that it is appropriate to use all the materials examined for the net cage and the floating collar.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.7-11
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• 2009

The dynamic responses and drift forces in waves of a floating circular fish cage are analyzed considering hydroelastic effects. The method of generalized mode is used to calculate the hydroelastic responses of the floater of cage. The elastic mode shapes, generalized mass, and stiffness in dry mode are evaluated by using a structural analysis code. The higher-order boundary element method is adopted to analyze the interaction between fluid and deformable structure. Some results of vertical motions and drift forces are shown and compared with those for a rigid body.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.2
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• pp.201-208
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• 1999

To develop a new fish cage which is required for offshore or moving cage culturing system has been gradually increased against being closely dense of fish cage in shallow water. Though submersible fish cage culturing system is essential technology for converting from shallow water into the offshore, it was pointed out the serious problem about stability of which are sinking and floating state. This study is presented conceptual design of submersible fish cage centered with a mooring steel pile to acquire stability and faculty. Design of mooring steel pile for submersible fish cage culturing system needs to carry out optimal design of mooring steel pile for which much efforts are required. Formulation and optimal design process of submersible fish cage are organized into using Sequential Quadratic Programming method of numerical optimization. For submersible fish cage system centered with a mooring steel pile, process of the optimal design is proposed and the optimal solutions are obtained.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.75-80
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• 2010

The paper is that study method to reduce bad influence that act to the floating fish cage by effect of environment in sea. Fish cage is controlled buoyancy using air control. According to marine environment, it is descend automatically to set-up depth and rise on the surface of the sea. The paper is the preceding research for a practical application. The fish cage simplified with the spherical float body. Then a control algorithm and a program developed by the experiment. And we did modelling by bond graph technique, and controlled by the practical reference model for PID control.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.30-34
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• 1988

In roastal fish farms the farmers, especialy engaging in dealing with the floating cage culture, going to know about relationships between holding capacity and water quality in cage. Some of water quality managers and specialists studing physiological ecology understand that the key of water quality management concerned fish farming is budget of dissolved oxygen. This paper deals with oxygen budget in floating cage of the yellow tail farms at southern coastal area in Korea. The sampling station is located at Konli-Do fish farm near Chungmu, and the data is collected for 24 hours from 3:00 p.m. 8th September 1987. In result, the needed oxygen coming after the consumption by the rearing fish had been supplied with the tide current exchange, the sum of oxygen produced by phytoplankton photosynthesis and diffused from atmosphere are no more that $43\%$ for the needs of sea water consumption included respiration of planktons and decomposition of organic matters. The optimum holding capacity of cage is possible to compute with the calculation of minimum diurnal water exchange rate $[Qin{\cdot}V^{-1}\;(C-\bar{c})]$ through net mesh of cage.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.2
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• pp.79-87
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• 2016

Mobile fish-cage was developed assuming a cage net with an enclosed area, which and estimated the hydrodynamic characteristics of the cage through the model experiment. Flux-shielding plates, installed in the bow were compared with the resistance test carried out by making a hole, bilge keel and stud, and basic block flow rate consisting of the results to a flat surface plate. The experimental results confirmed the improved resistance performance effect of 3~6% in the bilge keel and the stud form. To assess the stability of the fish-cage, evaluation of the stability in accordance with the stability criteria for determining the floating docks had confirmed that it satisfied the static stability performance under operating conditions at sea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.2
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• pp.117-124
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• 1996

The real size submersible fish cage($L{\times}B{\times}D$, $3{\times}3{\times}6$m)system consists of the compressed air equipment was made in order to control efficiently in case of heavy weather or environmental pollution such as red tide, and then carried out experiment on the submersible functions and safety for that cage at Koje inland sea in 14th June, 1995. The authors could confirm that the submersible cage was very stabilized it's submersible functions and safety when the cage was floating and sinking at sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.661-665
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• 2001

This paper deals with optimal mooring system to secure fish cage in a desired location, Through field investigation and paper works, we surveyed disasters by breakdown of cage frame and mooring system due to higher wave attack and selected compliant buoy mooring method for shallow water mooring system against severe coastal external forces. To analyze interaction between external forces and compliant buoy mooring system, theoretical model has developed as quasi-static nonlinear analysis. After verifying the feasibility of the numerical model compared with experiment, static analysis has tried for various mooring systems with different angle of array, number of mooring points, length of horizontal and inclined rope. Optimal mooring method using compliant buoy has selected for fish cage through numerical simulation. This results can apply for preliminary design for cage mooring system.