• Journal of the Korean Institute of Navigation
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• v.21 no.3
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• pp.83-90
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• 1997

Damage stability is generally very important as a part of rescue technique of damaged ship and also in connection with the requirements of MARPOL73/78[2]. Damage stability calculation program has been developed and suggest, which can be used on an onboard computer for any operating drafts. The program is based on lost buoyancy method for calculation of final drafts, and also based on added mass method for calculation of residual righting arm. The numerical method suggested by Hamamoto-Kim[6] is adopted for calculation of intact righting arm(GZ). The model experiments on damage stability are also carried out in a small tank with tanker model 2.385 meters long. The experimental results are compared with the calculations by the suggested method.

• Bulletin of the Society of Naval Architects of Korea
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• v.14 no.3
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• pp.1-4
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• 1977

The computer aided ship design and construction has become very popular one in a ship yard recently. For one of such a purpose a program is developed with Aitken's iterative interpolation method. From the sample calculation we can conclude that the program has a reliable acquracy for the calculation of hydrostatic data or loading manual. And also the program can be applicable to a ship construction by careful selecting of input data.

• Computational Structural Engineering
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• v.10 no.3
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• pp.15-21
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• 1997

Modern ocean-going vessels are highly dynamically loaded all-welded structures. Traditionally, this fact has been taken into account in the design of ship structures by keeping the overall stress level within permissible limits and by limiting notch effects in the design of local structures. With an improving knowledge of loads and the rapid development of calculation means more detailed calculation-based methods are increasingly introduced. A brief review on fatigue assessment methods used in the design of ship structures has been given during the 1993 IIW International Conference in Glasgow. The rapid development during recent years underlines the importace of the subject and justifies its extended discussion in this paper.

• Journal of the Korean Institute of Navigation
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• v.8 no.2
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• pp.43-50
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• 1984

When the static load is applied to the ship's hull the deflection due to the bending moment from longitudinal direction has not been considered in the usual calculation of maximum bending moment. In fact, however, the deflection of ship's hull must be affected by the above-stated bending moment, and in this case the value of the maximum bending moment would be lessened in comparision with the result of usual calculation. In this paper, the author at first calculated the difference between the two values in case of rectangular barge, and suggested a practical criterion of longitudinal strength.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.1-7
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• 2003

When a ship is course-keeping in the open seas, autopilot system is adapted. The design of autopilot system is very important for improvement of ship′s element research. Automatic steering system consists of autopilot device, power unit, steering gear, magnetic or gyro compass and ship dynamics. In order to evaluate automatic steering system of ships in open seas. we need to know the characteristics of each component of the system, and also to know the characteristics of disturbance to ship dynamics. In this paper, I provide evaluation method of autopilot navigation system of the fishing ship. Prediction method based on the principle of linear superposition is introduced for irregular disturbance. For the evaluation of automatic steering system of a ship, "performance index" is introduced from the viewpoint of energy saving and calculation method is frequency response analysis. Finally, I carried out calculation of sensitivity of control constants of autopilot with various conditions of ocean environments.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.3
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• pp.188-194
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• 2016

Accurate estimation of shear flows in thin-walled beam section is the key issue to evaluate shear stress distribution of ship hull transverse section under the shear forces acting on hull girder. It is regarded that the method using the warping functions obtained by finite element formulation is the state of the art of this field. Recently, however, IACS took effect the new version of CSR in which direct calculation process of shear flow was suggested. In the direct calculation process, shear flow of ship hull section can be obtained by the addition of determinate and indeterminate shear flows calculated respectively. So, in this paper, the shear flow evaluation codes based on the process proposed by IACS CSR and warping function based method were developed respectively. The calculated results of shear flows for the several examples of ship sections were compared with each other and considered in detail.

• Journal of Ship and Ocean Technology
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• v.11 no.1
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• pp.11-24
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• 2007

Better prediction of a ship's manouevrabilty in initial design stage is becoming more, important as IMO manoeuvring criteria has been activated in the year of 2004. In the present study, in order to obtain more exact and reliable results for ship manoeuvrability in the initial design stage, numerical simulation is carried out by use of RANS equation based calculation of hydrodynamic forces exerted upon the ship hull. Other forces such as rudder force and propeller force are estimated by one of the empirical models recommended by MMG Group. Calculated hydrodynamic force coefficients are compared with those obtained by empirical models. Standard manoeuvring simulations such as turning circle and zig-zag are also carried out for a medium size Product Carrier and the results are compared with those of pure empirical models and manoeuvring sea trial. Generally good qualitative agreement is obtained in hydrodynamic forces due to steady oblique motion and steady turning motion between the results of CFD calculation and those of MMG model, which is based on empirical formulas. The results of standard manoeuvring simulation also show good agreement with sea trial results.

• Selected Papers of The Society of Naval Architects of Korea
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• v.2 no.1
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• pp.79-105
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• 1994

A ship in waves is suffered from the various wave loads that comes from its motion throughout its life. Because these loads are dynamic, the analysis of a ship structure must be considered as the dynamic problem precisely. In the rationally-based design, the dynamic structural analysis is carried out using dynamic wave loads provided from the results of the ship motion calculation as a rigid body. This method is based on the linear theory assumed low wave height and small amplitude of motion. But at the rough sea condition, high wave height, compared with ship's depth, induce the large ship motion, so the ship section configuration under waterline is rapidly changed at each time. This results in a non-linear problem. Considering above situation in this paper, a strength analysis method is introduced for the hull girder among waves considering non-linear hydrodynamic forces. This paper evaluates the overall or primary level of the ship structural dynamic loading and dynamic response provided from the non-linear wave forces, and bottom flare impact forces by momentum slamming theory. For numerical calculation a ship is idealized as a hollow thin-walled box beam using thin walled beam theory and the finite element method is used. This method applied to a 40,000 ton double hull tanker and attention is paid to the influence of the response of the ship's speed, wave length and wave height compared with the linear strip theory.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.333-337
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• 2004

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wall. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wall is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wall are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.

• Bulletin of the Society of Naval Architects of Korea
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• v.20 no.4
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• pp.25-32
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• 1983

A series of model testes on a container ship in regular were executed. This paper presents the results of resistance, self-propulsion, and ship motion tests. The experimental results of ship motion measured on a towed model and a self-propelled model were compared with those of Japanese's model test showing fairly good agreements. The results of added resistance tests were compared with those of Japanese' model test and also compared with the calculation results by Gerritsma's method showing somewhat large discrepancies at higher speeds. Also the results of added resistance tests measured on a fixed model were compared with the calculation results by Gerritsma's method. Finally the results of self-propulsion tests were presented.