• Journal of Navigation and Port Research
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• v.37 no.4
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• pp.345-350
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• 2013

It is well known that the hydrodynamic forces and moments induced by the proximity of bank in confined waters, such as in a harbour or narrow channel affect ship's maneuvering motion. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic force between ship and breakwater is applied, and also, the characteristic features of hydrodynamic force acting on a large vessel in the proximity of a breakwater are described and illustrated. Furthermore, the effects of water depth and the lateral spacing between ship and breakwater are summarized and discussed.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1602-1613
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• 2016

Since Ballast Water Management Convention has been adopted, Ballast Water Management Convention is not effected yet. This convention will only enter into force 12 months after its ratification by 30 states, collectively representing 35% of world merchant shipping tonnnage. Morocco, Indonesia and Ghana have ratified this convention during last 29th IMO Assembly meeting which was held in November 2015. In 2016, Belgium, Fiji, Saint Lucia and Peru have become the latest countries to ratify the convention. As of now, 51 states and 34.87% combined merchant fleets are being calculated. BWM convention will be applied to not only new ships but also, existing ships after it is effected. Thus, existing vessel will be retrofitted a Ballast Water Treatment System according to D-2 Requirement until first IOPP nenewal survey after date of entry into force of the convention. Currently, about 65 BWTSs certified by Administration will be reported to IMO, even type of BWTSs is very various. Thus, a risk of each BWTS can be existed, and this existed risk can be also effected to ship's crew safety and protection of ship's own property. Therefore, we have evaluated a risk assessment for an existing vessel retrofitting an ultra violet type Ballast Water Treatment System which is mostly developed in the world. And we described the procedure of selecting a sample vessel, consequently, bulk carrier is selected because this vessel kind is mostly charged in the world. Especially, DWT 175K size is selected. Risk Assessment is using a HAZID and HAZOP method, evaluation method is referred to IMO Document "Considerated test of the Guidelines for Formal Safety Assessment (FSA) for use in the IMO rule-marking process(MSC/Circ.1203-MEPC/Circ.392)". The Risk Assessment Section is decided to 3 Nodes, Consequently, total risks have evaluated 51 items.

• International Journal of Safety
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• v.4 no.2
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• pp.6-11
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• 2005

The goals of the paper are to understand the impact damage behavior and identify the effect of surface protective materials on impact resistance in filament wound composite pressure vessels. For these, a series of low velocity impact tests was performed on specimens cutting from the full scale pressure vessel by the instrumented impact testing machine. The specimens are classified into two types, which are with and without surface protective material. The visualization for impact damage by two different impactors is made by metallurgical microscope. Based on the impact force history and damage, the impact resistance parameters were employed,rod its validity in identifying the damage resistance of filament wound composite pressure vessel was reviewed. As the results, the impact resistance of the filament wound composites and its dependency on the surface protective material were evaluated quantitatively

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.127-133
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• 2003

In this study, the impact analysis for the steel fender system that designed for protection of collision between vessel and bridge was performed The size of objective collision vessel assumed as 3000 dead weight tonnage(DWT). The impact forces and the impact energies were estimated by formulas of several design codes, and the steel fender system was designed based on the estimated forces and energy. The bow of objective vessel was modeled as rigid body, and bridge substructure was modeled as fixed support. Since, the impact analysis have the dynamic nonlinear features, such as, material nonlinear, large deformation and contact, explicit structural analysis program was used The analysis results presented that the impact forces formulas in codes have the sufficient conservativeness.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.8 s.239
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• pp.1109-1117
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• 2005

To identify damage that develops in filament wound composite pressure vessels subjected to low velocity impact, a series of impact tests was performed on specimens cutting from the full scale pressure vessel. The resulting damages by the three different impactors were assessed by the scanning acoustic and metallurgical microscope. Based on the impact force history and damage, the resistance parameters were proposed and its validity in identifying the damage resistance of CFRP pressure vessel was reviewed. As the results, the impact resistance of the filament wound composites and its dependency on the impactor shape were estimated quantitatively.

• Journal of the Korean Institute of Navigation
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• v.11 no.2
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• pp.61-72
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• 1987

When a ship is running in following seas, the encounter frequency is reduced to a very low one. In that case broaching, surfiding and capsizing phenomena are most likely to occur due to wave exciting forces acting on a ship in following seas. In this paper, the emphasis is mainly laid upon transverse stability of ships following seas, which is related to capszing phenomenon. The authors take the case that ship speed is equal to the wave celerity, i.e., the encounter frequency is zero. Hydrostatic force and moment due to Froude-Krylov hypothesis are calculated by line intergral method. Transverse stability is evaluated from hydrostatic force and moment. Through the application of present calculation method to box-shaped vessel, it is confirmed that the transversestability of a vessel can be reduced to critical level at wave crest.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.175-175
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• 2012

Proper shaft alignment is one of the most important actions during the design of the propulsion system. The stiffness of recently designed marine propulsion shafting has been increasing remarkably, whereas hull structures have become more likely to deform as a result of optimized design of the scantlings and the high tensile steel. Therefore, to obtain the optimum status in shafting alignment at the design stage, it is strongly recommended that the change of bearing reaction force depending on ballast/load condition, the bending moment force occurred by propeller thrust, elastic deformation of bearing occurred by vertical load of shaft mass and etc., should be considered. This paper dealing with introduction of shaft alignment concerning long shaft for high speed vessel and review its reliability evaluation theoretically.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.613-619
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• 2017

Recently, the size of container ships has been progressively increasing, and much attention is required for safe navigation in shallow areas such as coastal waters and ports due to increases in draft. It is necessary to understand the characteristics of ship motion not only in still waters but also with waves. Especially in shallow regions, squat due to the vertical movement of the ship can be an important evaluation factor for the safe navigation, and wave drift force acting in the horizontal direction can have a great influence on the maneuverability of a ship. In this study, a numerical simulation using computational fluid dynamics has been performed for the wave exciting force acting in the vertical direction and the wave drift force acting in the horizontal direction for a very large container vessel sailing in shallow zone. As a result, it was found that total resistance in still waters greatly increased in shallow water. Wave drift force was shown to decrease given longer wavelengths regardless of water depth. It was observed that the wave exciting force in shallow water was considerably larger than at other water depths. As wave height against the central part of the ship lowered, the aft side rose.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.463-470
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• 2014

In this paper, calculation of towing force required to tow the ship and experiments to verify its appropriacy are discussed. Friction, wind and wave-making resistance of vessel are considered to calculate towing force of specified vessel. Propeller resistance is also reflected and it is assumed that the propellers are locked. Node analysis to estimate additional resistance on towline is applied. Total towing force could be obtained by adding the ship's resistance and towline resistance. Experiments with training ship SAE YU DAL was executed to check the effectiveness of calculation methods and some comparison between experiments and calculation results was also done. From the comparative analysis, we confirmed that towing speed is primary terms in the calculation of towing force and propeller resistance is a major elements of ship's resistance with the increasing of towing speed. We can see that additional resistance induced by yawing of ship during towing have to be considered for total tow resistance.

• Journal of Ocean Engineering and Technology
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• v.25 no.4
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• pp.1-6
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• 2011

The installation of a topside structure can be categorized into the following stages: start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the module onto the floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with a significant wave height (1.52m). The effects of the hydrodynamic interactions between the heavy lifting vessel and the spar hull during the lowering and mating stages are considered. The internal forces caused by the load transfer and ballasting are derived for the mating phases. The results of the internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of the pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the mating phases, the internal force induced pitch motion is too small to have this influence. However, the effect of the internal force on the wave-induced heave responses in the mating phases is noticeable in the irregular sea condition because transfer mass-induced draught changes for the floating structure are observed to have higher amplitudes than the external force induced responses. The impacts of the module on the spar hull in the mating phase are investigated.