• Title/Summary/Keyword: naval vessel

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Experimental Study on Slow Drift Motion Damping (장주기 표류운동의 감쇠력에 관한 연구)

  • 김현조;홍사영;김진하
    • Journal of the Society of Naval Architects of Korea
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    • v.39 no.4
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    • pp.24-31
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    • 2002
  • In the present study, the amount of slow drift motion damping of shuttle tanker in still water and various environments is measured through free decay model test. Although the estimation of slow drift damping is essential in analysing slow drift motion of moored FPSO or DP controlled shuttle tanker, it is difficult to predict damping accurately by theoretical analysis. The estimation of drift damping depends on model test mostly. Through the model test, the amount of slow drift damping is measured and the effects of environments and thruster action on drift damping are investigated. The measured damping characteristics are expected to be used in the analysis on slow drift motion of moored vessel.

Comparative Results of Weather Routing Simulation (항로최적화기술 시뮬레이션 비교 결과)

  • Yoo, Yunja;Choi, Hyeong-Rae;Lee, Jeong-Youl
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.2
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    • pp.110-118
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    • 2015
  • Weather routing method is one of the best practices of SEEMP (Ship Energy Efficiency Management Plan) for fuel-efficient operation of ship. KR is carrying out a basic research for development of the weather routing algorithm and making a monitoring system by FOC (Fuel Oil Consumption) analysis compared to the reference, which is the great circle route. The added resistances applied global sea/weather data can be calculated using ship data, and the results can be corrected to ship motions. The global sea/weather data such as significant wave height, ocean current and wind data can be used to calculate the added resistances. The reference route in a usual navigation is the great circle route, which is the shortest distance route. The global sea/weather data can be divided into grids, and the nearest grid data from a ship's position can be used to apply a ocean going vessel's sea conditions. Powell method is used as an optimized routing technique to minimize FOC considered sea/weather conditions, and FOC result can be compared with the great circle route result.

A Study on Anti-Icing Technique for Weather-Tight Door of Ice-Strengthened Vessels (내빙선박용 풍우밀 문의 결빙방지 기법 연구)

  • Jeong, Seong-Yeob;Chun, Eun-Ji;Cho, Seong-Rak;Lee, Chun-Ju
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.6
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    • pp.575-580
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    • 2011
  • Icing problem of ice-strengthened vessels is an important issue when operating in low temperature environment and it can cause damage to deck machineries and emergency equipments. Many ice-strengthened vessels have since been constructed and operated in accordance with the ice class rules such as Det Norske Veritas (DNV), Russian Maritime Register of Shipping (RS), American Bureau of Shipping (ABS) and so on. Therefore winterization is defined as the preparation of a ship for safe operation. In this research, anti-icing performance tests of weather-tight door have been carried out at various temperature conditions($5^{\circ}C$, $-10^{\circ}C$, $-20^{\circ}C$, $-30^{\circ}C$, $-40^{\circ}C$) in the low temperature cold room facility and then, ambient temperature, specimen temperature, electric current and temperature of heating cable were measured during the test operations. This research describes the construction guidelines of weather-tight door based on anti-icing test results to apply to the full-scale vessels.

A Study on Quantifying Sailing Safety Considering Maneuverability of a Vessel (선박의 조종특성을 고려한 운항안전성능의 수치화 방법에 관한 연구)

  • You, Youngjun;Kim, Sewon;Kim, Woojin
    • Journal of the Society of Naval Architects of Korea
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    • v.54 no.2
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    • pp.113-124
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    • 2017
  • Recently, ship owners are requiring an assessment of sailing safety of a ship from an analysis considering maneuverability and environmental loads etc. In this paper, we propose a new approach to assess sailing safety by considering the prescribed parameters. The concept of sailing safety is developed from DP capability analysis and is based on the maneuvering simulations. While the ship is continuously disturbed due to irregular environmental loads during the simulations, it is steered to keep its course along the way points assumed along a straight path. After relative distances between four edges of the ship and allowable safety boundaries are calculated for 3 hours, the minimum values are obtained. The minimum distances are marked on a polar chart and we call this a quantified safe operation judgment chart which indicates quantified sailing safety.

Numerical Simulation of Two-dimensional Floating Body Motion in Waves Using Particle Method (입자법에 의한 파랑중 2차원 부유체 운동 시뮬레이션)

  • Jung, Sung-Jun;Park, Jong-Chun;Lee, Byung-Hyuk;Ryu, Min-Cheol;Kim, Yong-Soo
    • Journal of Ocean Engineering and Technology
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    • v.22 no.2
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    • pp.20-27
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    • 2008
  • A moon-pool is a vertical well in a floating barge, drilling ship, or offshore support vessel. In this study, numerical simulation of two-dimensional moon-pool flaw coupled with a ship's motion in waves is carried out using a particle method, the so-called MPS method. The particle method, which is recognized as one of the gridless methods, was developed to investigate nonlinear free-surface motions interacting with structures. The method is more feasible and effective than convectional grid methods in order to solve a flaw field with complicated boundary shapes.

Modeling and controller design of crabbing motion for auto-berthing (선박 자동접안을 위한 순수 횡 이동 모델링 및 제어기 설계)

  • Park, Jong-Yong;Kim, Nakwan
    • Journal of Ocean Engineering and Technology
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    • v.27 no.6
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    • pp.56-64
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    • 2013
  • Crabbing motion is the pure sway motion of a ship without surge velocity. Thus, it can be applied to a berthing operation. Crabbing motion is induced by a peculiar operation method called the push-pull mode. The push-pull mode is induced by using a combination of the main propeller and side thruster. Two propellers generating the same amounts of thrust and rotating in opposite directions produce some yawing moment on a vessel but do not induce longitudinal motion. With the additional operation of side thrusters, the push-pull mode is used to induce a large amount of lateral force. In this paper, three-degree-of-freedom equations of motion such as for the surge, sway, and yaw are constructed for the crabbing motion. Based on these equations of motion, a feedback linearization control method is applied to auto-berthing control for a twin-screw ship with side thrusters. The controller can deal with the nonlinearity of a system, which is present in the berthing maneuver of a twin screw ship. A simulation of the auto-berthing of a ship is performed to validate the performance of the designed controller.

Effects of Ship Speed and Ice Thickness on Local Ice Loads Measured in Arctic Sea (북극해에서 계측된 국부 빙하중에 대한 선속 및 빙두께 영향)

  • Lee, Tak-Kee;Lee, Jong-Hyun;Rim, Chae-Whan;Choi, Kyungsik
    • Journal of Ocean Engineering and Technology
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    • v.27 no.5
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    • pp.82-87
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    • 2013
  • The icebreaking research vessel ARAON conducted her second ice trial in the Arctic Ocean during the summer season of 2010. During this voyage, the local ice loads acting on the bow of the port side were measured using 14 strain gauges. The measurement was carried out during icebreaking while measuring the thickness of the ice every 10 m. The obtained strain data were converted to the equivalent stress values, and the effects of the ship speed and ice thickness on the ice load were investigated. As a result, it was found that a faster speed produced a larger stress, according to the variation in the peak values below an ice thickness condition of 1.5 m. Meanwhile, the effect of the ice thickness on the ice load was not clear.

Quay Mooring Analysis (안벽계류해석)

  • Tae-Myoung,Oh;Deuk-Joon,Yum
    • Bulletin of the Society of Naval Architects of Korea
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    • v.27 no.3
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    • pp.47-55
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    • 1990
  • This paper presents the quasi-static mooring analysis model for a vessel moored at the quay. The results of this analysis will aid the designer in determining the mooring configuration for the surface vessels subjected to wind, current and wave forces. And it will also help him in selecting the equipment for the fixed mooring system. The cumulative elastic behavior of the mooring lines invokes a complicated nonlinear problem since the mooring lines are relatively short and hang in air as noncoplanar configurations. This nonlinear mooring problem is solved in this paper by the load increment technique in which the external load is increased step by step taking all sources of nonlinearity into account.

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On a Compartment Layout Computer Model and Associated Data Structure (선박 구획배치 전산모델과 그 자료구조에 관한 연구)

  • Yong-Chul,Kim;Kyu-Yeul,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.27 no.3
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    • pp.117-126
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    • 1990
  • In the early stage of ship design process large number of alternative compartment layout designs are generated and examined iteratively. Therefore, the design efficiency will be considerably enhanced if a tool is available to perform this kind of iterative design process effectively in a relatively short time. This paper describes a method for generating and evaluating various alternative compartment layout designs in a personal computer. In this method, computer model of a compartment layout is generated by establishing the hierarchical structure of the entities forming a compartment and defining clearly the relationships among the entities. The evaluation of the design alternatives are effectively performed utilizing the computer model generated. The data structure for storing the defined compartment layout is explained and an illustrative example is given showing the application of the method to the design and evaluation of compartment layout of an Oceanographic Research Vessel.

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Study for Improving Fatigue Strength of Slurry Iron Sand Carrier (Slurry Iron Sand Carrier의 피로 강도 향상에 관한 연구)

  • Jang, Cheol-min;Kim, Dae-hun;Lee, Kyu-ho;Lee, Sang-bock;Koh, Myeong-Seob
    • Special Issue of the Society of Naval Architects of Korea
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    • 2015.09a
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    • pp.85-92
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    • 2015
  • In general, when ships are designed, structural strength and fatigue strength must be verified based on the relative rules respectively. In case of Slurry Iron Sand Carrier designed to carry Iron-Sand saturated at water content, there is no special consideration of fatigue strength analysis. However, this vessel is similar to Ore Carrier in consideration of the overall characteristics of loaded cargo and the shape of cargo hold. Therefore we verified fatigue strength based on fatigue analysis procedure of ore carrier in DNV Rules and carried out the study for improving of fatigue strength of Slurry Iron Sand Carrier.

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