• Structural Engineering and Mechanics
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• v.42 no.4
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• pp.531-549
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• 2012

Numerous oil tanker losses have been reported and one of the possible causes of such casualties is caused by the structural failure of aging ship hulls in rough weather. In aging ships, corrosion and fatigue cracks are the two most important factors affecting structural safety and integrity. This research is about effect on hull girder ultimate strength behavior of double hull oil tanker according to corrosion after Part I: stiffened panel. Based on corrosion data of Part I (time-dependent corrosion wastage model and CSR corrosion model), when progressing corrosion of fourtypes of double hull oil tankers (VLCC, Suezmax, Aframax, and Panamax), the ultimate strength behavior of hull girder is compared and analyzed. In case of the ultimate strength behavior of hull girder, when occurring corrosion, the result under vertical and horizontal bending moment is analyzed. The effect of time-dependent corrosion wastage on the ultimate hull girder strength as well as the area, section modulus, and moment of inertia are also studied. The result of this research will be useful data to evaluate ultimate hull girder strength of corroded double hull oil tanker.

• Journal of the Korean Institute of Navigation
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• v.18 no.4
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• pp.59-81
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• 1994

Korean property and liability insurance companies have underwrited hull insurance without proper undrewriting ability. But after April 1996. in case of Korean insurance market being opened the companies have to make hull insurance rate by themselves. Accordingly, in this study, the writer embodies important factors in making hull insurance rate by an empirical survey. In empirical survey, the writer used a questionnaire, 74 proper data was obtained from 96 officers working in making hull insurance rate in 12 Korean property and liablity insurance companies and 24 the foreign companies at home. Reliability was tested by Cronbach's Alpha and a conceptual validity by Factor Analysis. Hypothesis estabilished in this study was tested by Correlation and Multiple Regression Analysis. Results of testing hypothesis are as follows: Firstly, the traits of insurer and the assured influence significantly(P<0.05) on making hull insurance rate. Secondly, expected loss ratio, ship manager, ship's age, insured amount, level of the cost of repairing and salvage, shipowner, period of insurance, level of overseas rating, profit and expense, trading limits, ship's classification, conditions of insurance, and ship's size influence significantly(P<0.05) on making hull insurance rate.

• Korean Journal of Computational Design and Engineering
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• v.20 no.3
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• pp.281-290
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• 2015

The specific goal of the SMS (Ship Management System) is to increate ship safety and decrease maintenance fee. Equipment of ship is managed by PMS (Planned Management System), subsystem of SMS. But hull has not managed by ship manager. So, the Classes have developed the system for hull maintenance. Recently, the ship maintenance system has been developed for satisfying operator's requirements such as managing maintenance data as integrated platform, intuitive manipulation and design for ease of use. To reflect such requirement, 3D Model based maintenance system was introduced for ship in operation stage. Hull items that have to be inspected, repaired, replaced, are stored in integrated data platform with drawing, reports, and etc. and completely linked to 3D product Model. This system is specially developed for measurement and maintenance of hull thickness.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.431-441
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• 2014

The effects of hull-girder vibration on the fatigue strength of a Post-Panamax container ship are discussed in the present paper. Firstly, the short-term sea states are categorized according to the occurrence probability of each sea state. Time histories of hull-girder stress in short-term sea states are calculated by means of a nonlinear simulation code of ship response assuming that the hull-girder is rigid and flexible. Then, the calculated stress peaks are processed by the rainflow counting method, where two different counting procedures are used based on the considerations of crack propagation behaviors. Finally, the fatigue damage in life time of the ship in each categorized short-term sea state is estimated by means of Miner's rule. Based on the calculated results, the effects of hull-girder vibrations on the fatigue damage are clarified by disaggregated damage from short-term sea state.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.3
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• pp.1-12
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• 2004

In order to prepare the fuel-economic hull form design method for fine higher-speed ships, systematic theoretical and experimental study has been performed on the relation between hull form characteristics and ship's resistance and on the effect of the optimization of main hull form characteristics. The results of this study provide not only a great insight into the relation between ship's resistance and hull form characteristics, but also a proper direction of the optimization of main hull form characteristics for the improvement of ship's resistance characteristics.

• Journal of Ocean Engineering and Technology
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• v.37 no.5
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• pp.181-189
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• 2023

The fuel consumption of marine diesel engines holds paramount importance in contemporary maritime transportation and shapes energy efficiency strategies of ocean-going vessels. Nonetheless, a noticeable gap in knowledge prevails concerning the influence of ship hull conditions and propeller roughness on fuel consumption. This study bridges this gap by utilizing artificial intelligence techniques in Matlab, particularly convolutional neural networks (CNNs) to comprehensively investigate these factors. We propose a time-series prediction model that was built on numerical simulations and aimed at forecasting ship hull and propeller conditions. The model's accuracy was validated through a meticulous comparison of predictions with actual ship-hull and propeller conditions. Furthermore, we executed a comparative analysis juxtaposing predictive outcomes with navigational environmental factors encompassing wind speed, wave height, and ship loading conditions by the fuzzy clustering method. This research's significance lies in its pivotal role as a foundation for fostering a more intricate understanding of energy consumption within the realm of maritime transport.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.102-113
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• 2004

A name of 'Sea Ship' and 'River Ship' had been used based on the comprehension for the difference of ship's hull form in Chosun period. We can find a number of literature describing the situation which transferred the cargo from Sea Ship to River Ship because Sea Ship could not go upstream in the river of which the current is fast and the water depth is low. The reason why Sea Ship could not go upstream was that the bottom of Sea Ship was narrow, it means the non-flat bottom. Generally Sea Ship had short length, wide breadth, so L/B of 2.2∼3.0, and high draft and depth. River Ship has long length, narrow breadth, so L/B of 5.0∼6.3, and low draft and the flat bottom in order to adapt to the low water depth of the river.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.5
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• pp.314-321
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• 2021

In the existing whole ship analysis, topside was modeled as mass element. However recently, the topside is modeled as beam element due to the owner's requirement to improve the maturity of the whole ship FE model. To follow the owner'srequirement, detailed information for topside drawing and modeling, which may delay analysis schedule, is needed. However, it is hard to respond effectively to this matter due to the lack of study on the topside from the hull perspective. Therefore in this study, the effect of the topside on the hull is investigated when the topside is modeled as a mass element or beam element respectively. In addition, the interface modeling method is analyzed to verify modeling method used in the existing whole ship analysis. The results indicate that the interface and topside modeling method used in existing whole ship analysis are appropriate. This conclusion will be the technical basis for responding to owner's requirement about the topside modeling method.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.4
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• pp.349-355
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• 2015

Through the recent accident, the checking of ultimate hull girder capacity for container ship should be needed. Smith’s method is well known as the only simplified method to access rapidly for ultimate hull girder capacity except very expensive nonlinear F.E approach. This simplified method, however, is admitted to apply only to bulker and tanker in accordance with Classification Rules up to now. The targets of this study are to verify effectiveness of the simplified method for container ship’s ultimate hull girder strength and to propose the safety factor considering the local bending in double bottom structures due to out of plane loads through the nonlinear F.E analyses. Two different sized ships and three loading conditions which are pure bending, homo-loading and one-bay empty condition were used for this study. Based on the F.E results, the present study showed that CSR’s simplified method is available for the ultimate hull girder strength of container ship and over 1.2 of safety factor should be applied to consider the local bending effect in double bottom structures due to out of plane loads such as sea pressure an cargo.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.4
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• pp.317-324
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• 2011

When a ship proceeds in confined water, like canal, the water ahead of ship is pushed by hull. This pushed water returns to the side and under the hull, and this returned water will make fluid velocity higher at the side and under the hull, compared to the case in the infinite water depth. Due to the higher velocity, the pressure under the hull will decrease, resulting in the ship drop. This phenomenon is called "ship squat" and ship squat will result in various marine accidents. In this paper, for predicting ship squat, numerical calculation was carried out using commercial CFD code, FLUENT. To confirm wave pattern profile around the ship, VOF(Volume of Fluid) method was applied. The calculated results were compared with other paper's results and empirical methods.