• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.77-82
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• 2004

This study presents reliability assessment of merchant ships with focus on hull girder ultimate limit state, taking into account the time-dependent effects of corrosion, fatigue cracking and local denting. Some considerations for establishing a reliability-based repair and maintenance scheme are also made so as to keep a ship's hull girder strength reliability at an acceptable level even later in life.

• Journal of the Korean Institute of Navigation
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• v.13 no.2
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• pp.57-73
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• 1989

This paper presents a practical method to predict the characteristics of ship manoeuvring motions. A attempt is made to calculate the manoeuvring motions utilizing principal particulars of ship hull, properller and rudder as basic input data. The mathematical models, which describe the ship manoeuvring motions, are developed on the basis of MMG(5), Inoue(17), Hooft(18) and so on. Calcuations of manoeuvring motions for three kinds of typical characteristics, namely turning motion, zig-zag manoeuvre response and steady turning performance, are carried out. In order to examine the validity of the calculation method of this paper, simulations are run for seven merchant ships employed by Inoue(4). The computed results by present method are compared with full scale trials and Inoue's calculations(4). It can be concluded that the calculation method proposed in this paper is useful and pwoerful for prediction of characteristics of ship manoeuvring motions at the initial design phase or the application study on manoeuvring motions.

• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.4
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• pp.409-421
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• 2016

Container ships are prone to move at a greater speed compared to other merchant ships. The slenderness of the hull of container vessel is for better speed, but it leads to unfavorable motions. The pitch and roll are related and sometimes the vessel might be forced to parametric roll condition which is very dangerous. A fin attached to the ship hull proves to be more efficient in controlling the pitch. The fin is fitted at a lowest possible location of the hull surface and it is at the bow part of the ship. Simulations are done using proven software package ANSYS AQWA and the results are compared. Simulations are done for both regular and irregular seas and the effect of fin on ship motion is studied. P-M spectrum is considered for various sea states.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1997.10a
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• pp.35-41
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• 1997

China has integrated maritime safety system which positively and effectively ensures safe navigation and environmental protection. This paper gives brief account on maritime safety rules and regulations, adminstrations and management mechanism, navigation aids and facilities, maritime communication and GMDSS etc. China is a developing country with fast economical growth. With a long coastline of 18,000 kilometers, and 5,000 more islands, China has a fairly developed shipping industry. China also sits in IMO Council as A member. In China , there are over 200 ports with an annual hadnling capacity of over 10,000 tons of cargo ; there are over 4,000 coasters and ocean-going ships with more than 3 million seafarers of which 1/3 being officers ; there are an aggregate gross tonnage 17 million gt for merchant ships. China ranks No.5 shipping country in the world as shown by Lloyd's Maritime Information Services Ltd. 1995. The Chinese shipping industry plays an important role in both domestic transportation and foreign trade. The Chinese government always attaches great importance to maritime safety . Since 1949, and from the adoption of reform-opening policy, China has gradually formed an integrated maritime safety system.

• Journal of Navigation and Port Research
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• v.35 no.2
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• pp.137-147
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• 2011

The prime objective set for paper is to identify what are the women seafarers' problems and concerns regarding employment on cargo ships. From the cargo ship point of view, the question then is how to provide sufficient solutions for women seafarers in the male-dominated workplace of the ship through Corporate Social Responsibility(CSR) activities. The methodologies of study combine qualitative and quantitative research methods. The progress of research is to conduct a survey by asking a consistent set of key opinion leaders from the Republic of Korea. Moreover, to evaluate the elements of the result, the research explores the way in which we should consider giving priority to aspects of the problem. Finally, based on the terms of CSR, the author recommends measures to support the needs of women when they are employed onboard the world's merchant vessels.

• Journal of Ocean Engineering and Technology
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• v.34 no.6
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• pp.387-393
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• 2020

Frictional resistance comprises more than 60% of the total resistance for most merchant ships. Active and passive devices have been used to reduce frictional resistance, but the most effective and practical device is an air lubrication system. Such systems have been applied in several ships, and their effects have been verified in sea trials. On the other hand, there are some differences between the results predicted in model tests and those measured in sea trials. In this study, numerical analyses were carried out for a model and a full-scale ship. A new extrapolation method was proposed to improve the estimation of the full-scale resistance of a ship with an air lubrication system. The volume of fluid (VOF) method was considered for the numerical models of the air layer. The numerical method was validated by comparing the experimental data on the air layer pattern and the total resistance.

• Transactions of the KSME C: Technology and Education
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• v.3 no.1
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• pp.29-36
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• 2015

Some major companies representing Korea's ship building actively take part in building Oil & Gas offshore which produces both oil and gas from the ocean. Merchant ships become enlarge and high-powered electric as well as increasing number of Oil & Gas offshore. Thus, maritime university cadets are pushed to participate in onboard training on 440V to 6,660V high voltage ships. Although they have difficulty and danger from onboard training course on high voltage ships, their curriculum is still focusing on the training on low voltage ships. Therefore, this study is to suggest the upcoming education measures based on the questionnaire survey and analysis from the Maritime cadets who had experienced in high voltage ships.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.3
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• pp.145-152
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• 2013

Recently, with oil price jumping and environmental issues, Green ship is paid deep attention to by ship owner, operator, builder, class and government. Fuel efficiency and reduction of $CO_2$ emissions are expected to have a strong influence on the design and operation of merchant ships. Many ship owners and operators are seeking the more economic method by the best operating route and the application of reliable and effective energy saving devices. With the Energy Efficiency Design Index (EEDI) in 2013 attention will more than ever be focused at achieving maximum fuel economy in the hydrodynamic design of hull forms, their appendages and propellers. IMO requirements for $CO_2$ emission for ships will now be implemented for vessels ordered from 1st January 2013. So far, a lot of new idea and patents have been proposed, tested, claimed and applied for various kinds of ship type. This paper shows numerical and experimental work related to a study on a energy saving devices particularly for fuller ship such as merchant vessel of Tanker and Bulker. From the bare hull wake measurements, typical upper/lower asymmetry of hull wake at the propeller disk was found. The pre-swirl duct have been designed and reviewed to recover the loss of propeller running in that condition. The general function of the pre-swirl duct was set to work against this asymmetry of wake and generate pre-swirled flow into the propeller against the propeller rotating direction.

• 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.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.5
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• pp.60-67
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• 2003

For risk or reliability assessment of ship structures against particular hazardous situations such as total loss or sinking due to hull girder collapse, the short-term based response analysis rather than the long-term response analysis is required to determine wave-induced bending moments when the ship encounters a storm of specific duration and with a specified small encounter probability. In the present study, the effects of operational condition and sea states on wave-induced bending moments of large merchant vessels are investigated. A series of the short-term response analyses for a hypothetical VLCC and a Capesize bulk carrier (CSBC) are carried out with varying operational condition and sea states which include ship speed, significant wave height and wave persistence time, using the linear-strip theory based program ABS/SHIPMOTION and the MIT sea-keeping tables. The computed results are also compared with the IACS design formula predictions. The results and insights developed from the present study are summarized.