• Journal of Ship and Ocean Technology
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• v.3 no.1
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• pp.27-41
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• 1999

The objective of the paper is to study the impact of changing the traditional hull design of bulk carriers by providing them with a double hull while keeping the same deadweight. It is demonstrated that by introducing the double hull the structural reliability is increased throughout the entire life and also the extend of the needed repair is reduced. The results are obtained with recently developed mathematical tools for the reliability assessment of ship hulls subjected to the existence of multiple cracks both in the stiffeners and in the plating and it models the crack growth process. The effect of corrosion is represented as time dependent. The long-term stress range acting on the elements is defined as a function of the local transverse pressure of the internal cargo and outside sea water combined with the stresses resulting from the longitudinal bending of the hull, which is a combined with the stresses resulting from the longitudinal bending of the hull, which is a combineation of horizontal and vertical bending moments. The effect of maintenance actions is modelled as a stochastic process. The results show that a different design of the midship section improves the structural safety and also the economy with respect to structural repair of bulk carriers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.11-15
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• 2003

Ennin is a Japanese buddhist monk who traveled Tang from Jun. 13, 838 A D. to Dec. 14, 847 A D. in lunar's calender and wrote lengthy diary through the travel. This diary contained not only his wandering and triumphs but also politics, economy, social culture, religion, diplomatic policies, militaries, geography, transportations and administrations. Furthermore, the beginning of his diary dated Jun. 13, to July 3, 838 A. D. is recorded in the manner of ship's logbook entries. Many terms of navigation and naval architecture appears on it. It is very important to understand them for study ancient ship and its navigation skill. This Per aims to invest the meaning of “no-a” obviously refers to some part of hull of the ship upon first step to annotate the terms which are appeared in the diary.

• Journal of Ocean Engineering and Technology
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• v.30 no.5
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• pp.374-380
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• 2016

The large drift and angle of attack motion of an ROV (Remotely operated vehicle) cannot be modeled using the typical hydrodynamic coefficients of conventional straight running AUVs and specific slender bodies. In this paper, the ROV hull is divided into several simple-shaped components to model the hydrodynamic force and moment. The hydrodynamic force and moment acting on each component are modeled as the components of added mass force and drag using the known values for simple shapes such as a cylinder and flat plate. Since an ROV is operated under the water, the only environmental force considered is the current effect. The target ROV dealt with in this paper has six thrusters, and it is assumed that its maneuvering motion is determined using a thrust allocation algorithm. Tracking simulations are carried out on the ship’s surface near the stern, bow, and midship sections based on the modeling of the hydrodynamic force and current effect.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.109-118
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• 1994

In this study, an optimization method to design the hull structure of the surface effect ships with twin hulls is proposed for the purpose of minimization of weight based on the regulations of DnV class, and computer programs following the method are developed. The method uses simple formulas as to bending and buckling strength of beams and plates to design local structures, and considers the effect of interaction between longitudinal girders and transverse web frames by grillage analysis and calculates torsional strength of the cross structure by the simplified method. Global optimization of the midship section is attained by integration of optimized substructures. According to optimized results by applying the method to the designed ship, reduction of 20 percent of hull weight can be shown, and optimum transverse frame space can be obtained.

• Journal of Ship and Ocean Technology
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• v.9 no.3
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• pp.23-32
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• 2005

Ship STEP(Standard for the Exchange of Product Model Data) which is composed of AP 215 (Ship Arrangement), AP 216(Ship Hull Form), AP 218 (Ship Structure), has been developed more than last 10 years and it is now at the stage just before IS(International Standard). It is expected that ship STEP would be used for the seamless data exchange among various CAD/CAM/CAE systems of shipbuilding process. In this paper the huge and complicated data structure of ship STEP is briefly reviewed at the level of ARM(Application Reference Model) and some abstract test cases which will be included as part of the standards are introduced. Basically ship STEP has common data model to be used without losing compatibility among those three different ship AP's, and it is defined as the modeling framework. Typical cases of data exchange during shipbuilding process, such as hull form data exchange between design office and model basin, midship structure data between shipbuilding yard and classification society are reviewed and STEP physical data are generated using commercial geometric modeling kernel. Test cases of ship arrangement at initial design stage and hydrodynamic data of crude oil carrier are also included.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.529-536
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• 2005

Recently the building of ultra large container ship are discussed among ship building companies and ship operating company who have a tendency to pursue the advantage of large scale of economy. These tendency will be continued for the time being, if ship-building skill and economical efficiency are available. As the enlargement of container ship size becomes hot issues in ship-building markets, the needs for re-arrangement of accommodation house in large container ship are proposed carefully in some researches. This study examined economical efficiency of re-arrangement of accommodation house in ultra large container ship. The separation between accommodation and engine room is proposed through out drawing works in initial design stage and we examined the merits and demerits of the separation in the view of economical efficiency. The RFR(Required Freight Rate) is considered as the objective function to evaluate the re-designed vessel. The economical benefits are analyzed in the view of ship operator and shipyard respectively.

• Bulletin of the Society of Naval Architects of Korea
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• v.4 no.1
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• pp.49-54
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• 1967

The authors considered the effects of trim in the small coastal passenger boat upon resistance in this paper. Any change of trim no matter how small, necessarily produces some effect upon resistance. The relations between the resistance coefficients and trim were investigated through the towing test of the Model $MCI-P_1-65$, Korean Standardized Ship, GT 70 tons passenger boat in the gravitational tank. The Lines of the Model are given in Fig. 1. Principal dimensions and other characteristics vary with the trim in general. Those values varied with the trim for $MCI-P_1-65$ are tabulated in table 1. The resistance was measured at five conditions such as even keel, 0.0273L, (original designed trim) 0.0473L, 0.0663L, 0.0873L trim by the stern, fixing the displacement corresponding to the designed load water line. Model was made of wood in length of 3.5 feet coated with varnish, and without appendages. As the artificial turbulent stimulator, the sand strip method was used. The results of model towing tests, correcting to water temperature of $70^{\circ}F$, were expanded to full scale using the Schoenherr's friction formula and surface roughness allowance coefficient of 0.0004. The authors point out, the following results. 1) Optimum trim which gives the minimum resistance exists for every speed at constant displacement and each comes to the same value. For $MCI-P_1-65$ optimum trim is 0.0673L trim by the stern(Fig.4-The cross curves of the resistancecoefficients). 2) At constant displacement, when LCB(longitudinal position of center of buoyancy) varies with the trim, there exists optimum value of LCB which gives minimum resistance for every speed and each comes to the same value. For $MCI-P_1-65$ optimum position of LCB is 8%L aft from midship section (Fig.6).

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.325-332
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• 2005

As ship builder companies have a tendency to pursuit the effect of scale economy, recently the ultra-large sized container ship is discussed very actively among them. It is expected that these situation will be continued for the time being. The need of accommodation re-arrangement is carefully proposed according to the tendency of ultra-large sized ship. In this paper, accommodation re-arrangement of ultra-large container ship is examined in the view of economy. We proposed separation of engine room and accommodation part through review and supplementaition of drawing generation in intial design stage. Also we investigated its merits and demerits to find out whether it can be realized or not in the view of economical efficiency. The RFR(Required Freight Rate) is considered as the objective function to evaluate the re-designed vessel. The economical benefits for increasing the number of TEU(Twenty-foot Equivalent Units)'s and the re-arranged space are analyzed in the view of ship owner and shipyards respectively.

• Journal of Navigation and Port Research
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• v.27 no.5
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• pp.593-597
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• 2003

Ennin was a Japanese buddhist monk who stayed in Tang from Jun. 13, 838 A.D. to Dec. 14, 847 A.D. in lunar's calender and wrote lengthy diary through the travel. This diary contained lots of information on the politics, economy, social culture, religion, diplomatic policies, militaries, geography, transportations and administrations of Tang China. Especially the beginning of his diary dated from Jun. 13, to July 3, 838 A. D. was recorded in the manner of ship's logbook entries. Many terms of navigation and naval architecture appeared on it. It is very important to understand them for studying ancient ship and its navigation skill. This paper aims to investigate the meaning of ‘Nu-A’ obviously referring to some part of hull of the ship as the first step to annotate the terms of navigation and naval architecture which were appeared in the diary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.1
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• pp.33-49
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• 1997

One of the most important missons that are imposed on merchant ship at sea is to accomplish the safe transportation of cargo loaded. Recently, a study on the seakeeping performance has been carried out on the development of evaluation system related to the synthetic safety of a ship at sea. The seakeeping performance is the ship's ability sailing at, and executing its misson against adverse environmental factors successfully and safely. Until now, however, there has not been any method of quantitative evaluation on the dynamic safety of the ship's cargo loaded. In this regards, this paper has introduced the evaluation method of dynamic safety of the ship's cargo. In order to evaluate the dynamic safety of cargo, the vertical and lateral acceleration which causes the collapse, racking and local structure failure of cargo was adopted as the evaluation factors in the ship's motions. The response amplitude of ship's motions in regular waves is manipulated by NSM (New Strip Method) on a given 2,700 TEU full container vessel under the wind forces of 7, 8 and 9 Beaufort scale. Each response of ship's motions induced by NSM was applied to short-crested irregular waves for stochastic process on evaluation factors and then vertical and lateral acceleration of each cargo was compared with significant amplitude of each acceleration. A representative dangerous factor was determined by comparing permissible values of stacking and racking forces occurred typically to the vertical and transverse directions with the container strength required on ISO 1496 at the positions of forecastle, poop and ship's midship respectively. Through the occurrence probability of the determined factor by Rayleigh's probability density function, the dangerousness which limits loads on container's side wall as an evaluation was applied in judging of the danger of the ship's cargo loaded.