• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.2
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• pp.147-153
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• 2014

The purpose of this paper is to examine the roll damping characteristics by bilge keels on the fishing vessel. Unlike other degree of freedom motions, roll motion is highly nonlinear. However the quantitative evaluation of roll damping combined with waves is very important for the fishing vessel. To reduce roll motion, roll motion stabilizers such as a bilge keel is used due to easy made and cheap cost rather than anti-rolling tank and fin-stabilizer. Authors paid attention to the shape of bilge keel and waves to grasp the roll damping for the fishing vessel and studied about the difference of tendencies of roll angle following the shapes of bilge keel. The model ship was the offshore large purse seiner and four types of bilge keel were used. The data from the experiments were provided and analyzed to investigate the rolling characteristics of the model ship being affected by the wave height, wave period and bilge keel shape. The results of the study showed that three types of the bilge keel have little effective, but only one has an effect on the roll damping. So bilge keel shape and its attachment method need to be a future study for the practical use in fishing vessel.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1100-1109
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• 2022

Herein, a case study was conducted on the bilge pumping performance of a 24,000TEU class container ship with an overall length of 400m. Although the bilge system of the 24,000TEU class container ship was designed in accordance with the rule requirements of the Classification Society, the bilge system did not satisfy the 2 m/s requirements of SOLAS Reg.II-1/35-1 under the rated flow rate and maximum flow rate conditions of the bilge pump installed in the ship. In particular, assumptions were made that No.1 ~ No.4 cargo holds were flooded and filled entirely by sea water and the evaluation of bilge pumping performance had been performed for No.1 ~ No.4 cargo holds. According to the evaulation results of the, the mean water velocity at the main bilge pipe for No.2, No.3, and No.4 cargo holds did not meet the 2 m/s criterion. To resolve this problem, in this study, the branch bilge pipe in each cargo hold was changed from 150A to 200A and the mean water velocity at the main bilge pipe for No.2, No.3, and No.4 was calculated as 2.479m/s, 2.476m/s, and 2.459m/s, respectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.28-33
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• 2020

Oil-related products have provided many benefits to humanity, but are significant contributors to environmental pollution. As per the International Maritime Organization (IMO) requirements, in the future, all ships must be equipped with filtering equipment and 5ppm bilge alarms that can help remove or reduce oil products during wastewater treatment. In this study, a UV fluorescence measurement system that can detect the oil components in wastewater containing both water and oil was developed. When an excitation wavelength of 254nm was used to irradiate the wastewater, the amount of UV at a divergent wavelength of 360nm was measured to measure the contamination. Based on the measurement, it was concluded that this system is suitable for use as the 5ppm bilge alarm proposed by IMO.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1835-1841
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• 2006

Demand of enhanced bilge separation sensor system has been recently increased due to the severe regulation reinforcement of MEPC(Marine Environment Production Committee). Up to date bilge separation sensor has to be extremely accurate and highly reliable. To design and build such a bilge separator. a precise oily water separation level sensor that distinguishes oil from water is critical. Three dimensional simulations have been carried out to figure out the characteristics of capacitive level sensors, which grounds the finding of the parameters required to design the sensors. The parasitic capacitance problem which is inherent to capacitive level sensors has been taken care of. This paper concludes with the future research direction that can be pursued with the newly defined parameters of the capacitive level sensors.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.611-619
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• 2008

In most shipyards Floating Dock-gate System is adapted for dry docks. For the safe launching of ships in dry docks, smooth operation of dock-gate must be guaranteed. So it is very important to grasp its behavior in waves for securing the high productivity and the safety of workers. Its seakeeping ability was estimated numerically at the floating conditions and the free roll decay and the seakeeping model tests of dock-gate was carried out with bilge-keels of 3 different widths which have a scale of 1 to 20. More than 20% decrease of roll motion was observed in irregular beam seas by applying a bilge-keel system to the dock-gate that is long and narrow.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.5
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• pp.17-25
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• 2003

Velocity field behind a container ship model with a rotating propeller has been investigated using PIV (particle image velocimetry) system. Four hundred instantaneous velocity fields were measured at 4 different blade phases and ensemble-averaged to investigate the spatial evolution of vortical structure of near wake within one propeller diameter downstream. The phase-averaged mean velocity fields show the potential wake and the viscous wake formed due to the boundary layers developed on the blade surfaces. The interaction between bilge vortex developed along the hull surface and the tangential velocity component of incoming flow causes to have asymmetric flow structure in the transverse plane.

• Journal of Fisheries and Marine Sciences Education
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• v.11 no.2
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• pp.184-202
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• 1999

The roll damping characteristics of the three models of a small fishing(3 ton class fishing vessel), such as the bare hull, hull with bilge keels, and hull with bilge keels and a central wing are investigated by the free roll and head waves tests in calm water in a towing tank with the various forward speeds, initial angles and OG's. The experimental results are compared with the numerical results of mathematical modelings by the energy method for these three models and the energy dissipation patterns are also compared. And the wave length variations are also included. The experimental results are compared with the numerical results of mathematical modelings by the energy method for these three models and the energy dissipation patterns are also compared. The roll damping moment of the models is increased for zero speed cases, but as the speed increases, the effect of the waves on the roll damping of the models with the additional devices is negligible due to the much increased damping caused by the lift increase.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.248-256
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• 2011

The inherent efficiency of a ship would be prior to any other quality factors in ship's safety, because lack of it may give rise to a serious sea casuality even if it were a light mistake in operation. And the representative casualty comes from a deficiency of stability and an operating error combined would be capsizing. The Korean offshore large purseiner looks to have a structural weak point with small range of stability in spite of her big initial metacentric height, and have various type of roll reduction devices in order to cover up the defect. The aim of this study is to grasp for the roll reduction characteristics of the purseiner with bilge keel only and a stern keel additionally attached. The results are summarized as follows; The rolling angle of the model ship was increased in accordance with increase of the wave period and height, especially at close to the natural wave period of her, and the trends were more distinguished in the situation of bilge keel only installation than in the stern keel additionally installed. And stern keel has not noticeable effect on the reduction of the roll in the light ship condition, but has a little effect in full load condition.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.3
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• pp.45-53
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• 2003

Discharging untreated bilge to the ocean is a cause of marine pollution. In general, bilge water contains free and/or emulsified forms of oil. Free form of oil can easily be separated by gravimetric flotation and/or proper filtration processes. However, those simple physicochemical processes could not separate emulsified oil without adding proper chemicals. Electrolytic flotation is one of promising technologies able to fulfill the effluent standard requirement, which is below 15 ppm of oil content. In this research, Electrochemical process consisting of electrochemical flotation basin was studied for the treatment of emulsified oil. In order to estimate, the effectiveness of oil separation equipment influent concentration of oil and HRT(Hydraulic retention time) were considered. Also, lab-scale electrochemical process was designed and operated in the condition of various HRT, current density, and electrode gap. Through the research, following results were obtained. From the experiment of bench scale electrochemical treatment process, it was demonstrated that the emulsified oil was treated effectively and the removal efficiency of emulsified oil from wastewater was increased with HRT and current density.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.132-133
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• 2005

A study to evaluate the fire extinguishing performance of the water mist system inside simulated machinery spaces according to IMO MSC/Circ.668 was performed. Fire tests were conducted inside a compartment having a area 100$m^2$(10m${\times}$10m) with a ceiling height of 10m and door opening of 2m${\times}$2m in size. Test fuels were used heptane, diesel, wood crib and mineral oil. Water mist nozzles were installed downward at ceiling and horizontally at bilge area. All fires in the test were extinguished within 15minutes of system activation and there was no reignition or fire spread.