• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.347-360
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• 2014

The auto-berthing of a ship requires excellent control for safe accomplishment. Crabbing, which is the pure sway motion of a ship without surge velocity, can be used for this purpose. Crabbing is induced by a peculiar operation procedure known as the push-pull mode. When a ship is in the push-pull mode, an interacting force is induced by complex turbulent flow around the ship generated by the propellers and side thrusters. In this paper, three degrees of freedom equations of the motions of crabbing are derived. The equations are used to apply the adaptive backstepping control method to the auto-berthing controller of a cruise ship. The controller is capable of handling the system non-linearity and uncertainty of the berthing process. A control allocation algorithm for a ship equipped with two propellers and two side thrusters is also developed, the performance of which is validated by simulation of auto-berthing.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.204-208
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• 2002

Mooring is the operation of securing a ship to a wharf or quay by means of rapes or chains. A. moored ship need not necessarily be truly stationary. It may be free to rise and fall with the tick or the loading and unloading of cargo or to oscillate in response to the action of the environmental forces. In this respect a moored ship is restricted to a limited amount of movement within well-defined bounds. This study is intended to analyze the tension of mooring lines by a FEM program, as the current velocities and working directions are varied. The motion of a berthed ship is studied concerning with the wave periods and the direction. Also the behavior of the modeled vessel are investigated for a berthed condition.

• Journal of Navigation and Port Research
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• v.29 no.9
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• pp.777-782
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• 2005

Maritime transportation consists of various situations such as navigation in the ocean, ship handling at harbor entrances, cargo handling and mooring in harbors. Generally, ships are built for the purpose of currying people and materials upon the seas. In order to accomplish the mission, a ship must be built to withstand the rigors of heavy weather and waves. In particular, the safety of ship motions at the entering/departing harbor and mooring under the effects of waves is very important for ship operation from the viewpoint of marine engineering. Therefore, safety and efficiency during entrance, departure, and mooring are extremely important aspects in the evaluation of ship operations from viewpoints of ship motions. However, the ship motions near a harbor entrance are not observed or studied as much. In this paper, to evaluate the difficulty of ship operations, field observations were performed using a new observation system with high accuracy in typhoon seasons, and grasp was done concerning about the time series characteristic that ship motions change rapidly within a harbor. Namely, such observations enable the quantitative safety evaluation under the effects of waves during ships entering and departing harbors in heavy weather.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.5
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• pp.447-452
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• 2016

The use of gas as fuel, particularly liquefied natural gas (LNG), has increased in recent years owing to its lower sulfur and particulate emissions compared to fuel oil or marine diesel oil. LNG is a low temperature, volatile fuel with very low flash point. The major challenges of using LNG are related to fuel bunkering, storing, and handling during ship operation. The main components of an LNG fuel system are the bunkering equipment, fuel tanks, vaporizers/heaters, pressure build-up units (PBUs), and gas controlling units. Low-pressure dual-fuel (DF) engines are predominant in small LNG-powered vessels and have been operating in many small- and medium-sized ferries or LNG-fueled generators.(Tamura, K., 2010; Esoy, V., 2011[1][2]) Small ships sailing at coast or offshore rarely have continuous operation at constant engine load in contrast to large ships sailing in the ocean. This is because ship operators need to change the engine load frequently due to various obstacles and narrow channels. Therefore, controlling the overall system performance of a gas supply system during transient operations and decision of bunkering time under a very poor infrastructure condition is crucial. In this study, we analyzed the fuel consumption, the system stability, and the dynamic characteristics in supplying fuel gas for operating conditions with frequent engine load changes using a commercial analysis program. For the model ship, we selected the 'Econuri', Asia's first LNG-powered vessel, which is now in operation at Incheon Port of South Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.1049-1059
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• 2017

After patrol corvett Cheonan was hit and sank on duty, the Republic of Korea Navy has tried to install hybrid propulsion system on naval ship to reduce vibration and noise problems during navigation. The hybrid propulsion system has advantage that propulsion motor can be propelled in low speed operation of the vessel. This can be a better quietness than a mechanical propulsion system which consists of a conventional internal combustion engines. And more economical operation is possible by using a propulsion motor in a low speed operation where a fuel efficiency of the internal combustion engine is poor. In this paper, we set up virtual ship on the basis of a combat support ship in the Republic of Korea Navy, economically compared and analyzed fuel consumption between conventional and hybrid propulsion system. As a result, it was confirmed that the fuel efficiency of hybrid propulsion system which use electric motor had been relatively improved.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.3
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• pp.198-205
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• 2021

In this paper, the effect of trim variation on the required power of 11,000TEU container ship was investigated under conditions considering the actual operation speed and draft. For each draft condition, the effective power (P_E) and delivered power (P_D) trends were investigated with changes in trim and ship speed. At this time, the displacement volume was fixed same as the value of the even trim condition and the both sinkage at the fore and after perpendicular are confirmed. The test ship speeds were determined by considering the operating speed. Both numerical and experimental methods were used to analyze the effects of trim variation. Numerical analysis results were used for evaluating the resistance performance, and the self-propulsion performance was estimated using experimental data obtained from model test.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1202-1208
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• 2020

In line with the current era of the 4th Industrial Revolution, it is necessary to prepare for the future by integrating AI elements in the ship sector. In addition, it is necessary to respond to this in the field of power management for the appearance of autonomous ships. In this study, we propose a battery-linked electric propulsion system (BLEPS) algorithm using machine learning's DNN. For the experiment, we learned the pattern of ship power consumption for each operation mode based on the ship data through LabView and derived the battery status through Python to check the flexibility of the generator and battery interlocking. As a result of the experiment, the low load operation of the generator was reduced through charging and discharging of the battery, and economic efficiency and reliability were confirmed by reducing the fuel consumption of 1% of LNG.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10b
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• pp.11-25
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• 1998

Many Countries have made efforts to assist ships navigate accurately , safely and expeditiously for the safety control against increasing marine traffic , in their coastal waters. However, they are exposed in spite of these efforts,to risks of casulaties and marine polluation caused by traffic congestion when ships are navigating through waterways approaches to ports or harbors and in narrow fairways. Therefore, efficient control of VTS in Port is necessary nowadays to provide ships with necessary service , which interacts with shipping and organize the flow of traffic so as to maximize the efficiency of the port or harbor while minimizing the risk of accident and environmental pollution. Even though the navigation condition of ships is very inferior compared to other ports in Korea, such as the big difference between the ebb and flood tide, the frequent fog, the narrow fairway , the density of navigation traffic in Inchon Port is high and transportation quantity of dangerous cargoe increases gradually. In cosideration of the characteristics of natural circumstance and traffic circumstance the VTS established newly in Inchon port have to operate efficiently. The purpose of this study is to help efficient operation of VTS in Inchon port by accomplishing both the literature research and questionnaire survey. Questionnaire survey was read to the VTS personnel in Inchon Port and customer familiar to Inchon Port such as ship navigators, pilots, shipping companies and so on. Most of ship navigators who occupy half of the respondents are Korean Officer who had responded while they were calling at Inchon port. The conclusions and recommendations includes ; First, the service area should be extended over Designated area to provide the vessel with navigational assistance service regarding the information of traffic congestion area, fishing boat and small ship's activities. Second, the types of information service to be offered are ship's movement and weather condition inthe vicinity of the port and state of fairway in the approaching channel to thte fairway. Third, VTS personnel should be upgraded by the on-the-job training and continuous simulation training as well as supplement of the qualified personnel for VTS operation. Fourth , the Harbor Master System to be introduced for safe navigation and efficient port operation.

• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.633-645
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• 2017

This study proposes a statistical procedure for analyzing container ship operation data that can help determine fuel consumption patterns. We first investigate the features that affect fuel consumption and develop the prediction model to find current fuel consumption. The ship data can be divided into two-type data. One set of operation data includes sea route, voyage information, longitudinal water speed, longitudinal ground speed, and wind, the other includes machinery data such as engine power, rpm, fuel consumption, temperature, and pressure. In this study, we separate the effects of external force on ships according to Beaufort Scale and apply a partial least squares regression to develop a prediction model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.72-73
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• 2021

As discussions of the International Maritime Organization for the introduction of the Marine Autonomous Surface Ship (MASS) began in earnest, discussions were conducted to prioritize cybersecurity (Cyber Risk Management) when developing a system to support MASS operation at the 27th ENAV Committee Working Group (WG2). Korea launched a technology development project for autonomous ships in 2020, and has been promoting detailed tasks for cybersecurity technology development since 2021. MASS operation in a digital maritime communication system environment requires network security of various digital equipment that was not considered in the existing maritime communication environment. This study introduces the basic concept of network security equipment to support MASS operation in the detailed task of cybersecurity technology development, and defines the network security equipment interface for MASS ship application in the basic stage.