• Journal of the Society of Naval Architects of Korea
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• v.35 no.2
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• pp.63-73
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• 1998

Due to the collapse of corrugated bulkheads subject to accidental flooding which is thought to be a primary cause of bulk carrier losses International Maritime Organization(IMO), the International Association of Classification Societies(IACS) and the leading classification societies are taking a growing concern for the structural safety of corrugated bulkheads of bulk carriers. To prevent progressive collapse of corrugated bulkhead in flooded condition particularly of forward cargo ho1d they try to make rules which require reinforcement of corrugated bulkhead structure. However, we are still confronted with the urgent problem of more accurate and efficient ultimate strength assessment for corrugated bulkheads. This paper develops a special purpose nonlinear FE program for analyzing progressive collapse behavior of corrugated bulkheads subject to lateral pressure loads. As verification examples, the program is applied to collapse strength analysis of steel corrugated bulkhead test model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1166-1176
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• 2011

The prospect in opening the arctic trade transportation route on a year-round basis offers vast opportunity of exploring untapped resources and shortened navigational routes. In addition, the environment's remoteness and lack of technical experiences remains a big challenge for the maritime industry. With this, engine designers and makers are continually investigating, specifically optimizing propulsion shafting system design, to meet the environmental and technical challenges of the region. The International Association of Classification Society, specifically machinery requirements for polar class ships(IACS UR13), embodies the propulsion shafting design requirements for ice class vessels. However, the necessity to upgrade the various features of the unified rules in meeting current polar requirements is acknowledged by IACS and other classification societies. For the polar class propulsion shafting system, it is perceived that the main source of excitation will be the propeller - ice load interaction. The milling - and the impact load, in addition to the load cases interpreted by IACS, contribute greatly to the overall characteristic of the system and due considerations are given during the propulsion design stage. This paper will expound on the excitation load estimation factors affecting the dynamic response of the different propulsion shafting system design. It is anticipated that detailed understanding of these factors will have a significant role during propulsion shafting design in the future.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.4
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• pp.598-605
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• 2010

The structural design of oil tankers and bulk carriers should be performed based on the Common Structural Rules(CSR) which were recently established by the International Association Classification Societies(IACS). At first, in the structural design viewpoint, the scantling and hullweight based on the CSR should be compared with those of existing rules, and then a minimum weight/cost design should be performed by considering the variation of the number of web and the material property. In this study, the optimum web space and material property will be proposed by performing a minimum weight/cost design of a large oil tanker, and the results will be compared with those of existing ship. The longitudinal members are determined by SeaTrust-Holdan developed by the Korean Register of Shipping(KR), and the transverse members are determined by NASTRAN and PULS.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.12
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• pp.815-821
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• 2015

Maritime safety has been more critical recently due to the occurrence of shipboard accidents involving prime movers. As such, the propulsion shafting design and construction plays a vital role in the safe operation of the vessel other than focusing on being cost-efficient. Smaller vessels propulsion shafting system normally install high speed four-stroke diesel engine with reduction gear for propulsion efficiency. Due to higher cylinder combustion pressures, flexible couplings are employed to reduce the increased vibratory torque. In this paper, an actual vibration measurement and theoretical analysis was carried out on a propulsion shafting with V18.3L engine installed on small car-ferry and revealed higher torsional vibration. Hence, a rubber-block type flexible coupling was installed to attenuate the transmitted vibratory torque. Considering the flexible coupling application factor, reduction gear stability due to torque variation was analyzed in accordance with IACS(International Association of Classification Societies) M56 and the results are presented herein.

• Special Issue of the Society of Naval Architects of Korea
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• 2015.09a
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• pp.46-49
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• 2015

Common Structural Rules (CSR) about bulk carriers and double-hull oil tankers of International Association of Classification Societies (IACS) has been applied to ships contracted for construction since April 2006. By unifying each society's rules, the difference of opinion in the between shipyard and ship owners, classification was reduced, and CSR has been evaluated by rules the safety structure more enhanced. However, The CSR about the bulk carriers and double hull oil tankers, important design content standards, such as the local scantling calculation, static/dynamic load case and corrosion margin and etc., are different. Therefore in order to combine the CSR, the Harmonized CSR for bulk carriers and double hull oil tankers (H-CSR) was issued on 1, January, 2014, and will be apply to ships contracted for construction after 1st July 2015. It is necessary to verify the H-CSR to optimize the structural arrangement because effective date is not far off. In this study, we compared the impact by rule change for the hull girder shear strength of bulk carriers between CSR and H-CSR in respect of the yielding and buckling strength.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.321-328
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• 2015

In recent years, there has been an increasing demand to apply the new IACS(International Association of Classification Societies) standards for ice and polar-classed ships. For ice-class vessel propulsion system, the ice impact torque design criterion is defined as a periodic harmonic function in relation to the number of the propeller blades. However, irregular or transient ice impact torque is assumed to occur likely in actual circumstances rather than these periodic loadings. In this paper, the reliability and torsional vibration characteristics of a comparatively large six-cylinder marine diesel engine for propulsion shafting system was examined and reviewed in accordance with current regulations. In this particular, the transient ice impact torque and excessive vibratory torque originating from diesel engine were interpreted and the resonant points identified through theoretical analysis. Several floating ice impacts were carried out to evaluate torque responses using the calculation method of classification rule requirement. The Newmark method was used for the transient response analysis of the whole system.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.213-220
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• 2010

Following the application of Formal Safety Assessment(FSA) to bulk carriers, crude oil tankers and large passenger ships, an urgent need to consider the safety of general cargo ships has recently been raised through the International Maritime Organization(IMO)(IMO, 2006a), and related FSA studies are being carried out by International Association of Classification Societies(IACS) as a preparatory work for the discussion on the issue of general cargo ship safety in the IMO committee. FSA is a structured and systematic methodology which is based on the techniques of risk analysis and cost benefit assessment to assist in the decision-making process, and aims at enhancing maritime safety, including protection of life, health, the marine environment and property. FSA can be used as a tool to facilitate the development of regulatory changes equitable to the various parties, with a view to aiding the achievement of consensus, and to help in the evaluation of new regulations and in making a comparison between existing and possibly improved regulations(IMO, 2007). This study aims at verifying the usefulness of FSA methods as a tool to conduct a safety assessment of general cargo ships flying the Korean flag, and providing useful information on 'the safety of general cargo ships' for IMO committee's discussion on the matter at a future session. FSA comprises five steps, however, steps 1(Hazard identification) and 2 (Risk analysis) from the FSA study for the Korean-flagged general cargo ships are discussed in this paper.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.1-7
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• 2013

In past decades, a maximum standard vessel size for chemical tankers is not normally larger than 55,000 TDW due to the characteristic of chemical product shipment which is so variable but small quantity unlike single product carries such as crude oil tankers. These days, as demand of very large chemical tanker is rising due to the change of market trend of chemical product shipment, 75,000 TDW class chemical tanker has been developed. The newly developed vessel's structure has been designed based on CSR (Common Structural Rule) for double hull oil tankers (hereafter CSR) published by IACS (International Association of Classification Societies). However, due to the large difference from typical oil tankers, many items should be specially considered such as on deck transverse and corrugated bulkheads. In addition, two longitudinal bulkheads without upper stool have been constructed in order to maximise the number of cargo tanks and the volume of each cargo tanks. In this study, key word of the vessel has been briefly reviewed and the structural reliability of the proposed vessel has been investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.366-373
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• 2020

According to Article 77 of the Ship Safety Act and Article 97(2) of the Enforcement Ordinance of the Ministry, the Recognized Organization (RO) personnel (ship surveyors) responsible for statutory survey shall have educational qualifications and experience in a specific field or obtain a license under the National Technical Qualifications Act. However, graduates from maritime high schools and those who completed the short-term course of the Ocean Polytec did not satisfy the qualification standards for the RO personnel since they did not graduate from the departments of maritime/fisheries or shipbuilding. Major shipping countries such as the United Kingdom, the United States, and Canada use the IACS (International Association of Classification Societies) regulations, and the Ship Safety Act in Japan has eliminated the qualification requirements for ship surveyors. In particular, under the IMO (International Maritime Organization) and IACS regulations, the RO personnel shall have as a minimum the following formal educational background: a degree or equivalent qualification from a tertiary institution recognized within a relevant field of engineering or physical science (minimum two years' program); or a relevant qualification from a marine or nautical institution and relevant sea-going experience as a certified ship officer; and competency in the English language commensurate with their future work. Considering that Article 17 of the Enforcement Decree on Public Officials Appointment Examinations prohibits educational restrictions and there are no educational restrictions on the qualifications of British and Japanese surveyors, if the maritime high school graduates have sufficient sea-going experience, education, and training, they could be recognized as meeting the qualification requirements. Moreover, those who completed the short-term course of the Ocean Polytec could also be recognized as meeting the qualification requirements because they are required to have at least a professional bachelor's degree (in the case of a third-class CoC (Certificate of Competancy)) and some sea-going experience after completion.