• Journal of the Society of Naval Architects of Korea
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• v.56 no.3
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• pp.217-230
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• 2019

In this study, a fatigue damage estimation for an ice-going vessel navigating through broken ice fields was carried out. A numerical model to simulate the interaction between ice and structure developed using the finite element method was introduced. Time series of stresses calculated by the proposed model and the corresponding fatigue analysis results are presented. The numerical model enables the long time analysis through an efficient interaction model, the application of the periodic media analysis and the convolution integral, and it allows the stress time history to be extracted directly using the finite element method. To describe the probability distribution of stress amplitudes, the 2-parameter Weibull model was applied to the calculated stress time history, and the fatigue damage was calculated using the Palmgren-Miner rule. Finally, the fatigue damage considering the ice conditions of the Baltic Sea was calculated using the proposed method and LR method, and the results were compared to each other.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.3
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• pp.231-241
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• 2019

In this study, a simplified analysis method was developed to evaluate the fatigue damage of an ice-going ship under broken ice condition. The global ice load, which is essentially calculated at the design stage of the Arctic vessel, and the hull form information were used to estimate the local ice load acting on the outer-shell of the ship. The local ice load was applied to the finite element analysis model, and the Weibull parameters for the target fatigue point were derived. Finally, fatigue damage was evaluated by applying the S-N curve and the Palmgren-Miner rule. For the verification of the proposed method, numerical analyses using direct approach were performed for the same conditions. A numerical model that implements the interaction between ice and structure was introduced to verify the local ice load and the stress calculated from the proposed method. Finally, the fatigue analyses of the Baltic Sea for actual ice conditions were performed, and the results of the proposed method, the method using numerical analysis, and the LR method were compared.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1761-1771
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• 2016

In respect of the existing relation between Sea-going Vessels and Vessels at anchor, Korean Maritime Safety Tribunal has applied 'Ordinary Practice of Seamen' that is regulated by the article No. 2 of COLREG. That is, general navigation rule is not applied between the two vessels, and the action to avoid collision of vessels by utilizing experience knowledge of the seamen. However, the content of the Ordinary Practice of Seamen included in the revised plan in the process of 2011 "Maritime affairs Safety Act" revision was deleted in the screening of the Office of Legislation due to the reason that it could not specified when the content of deed is not concertized. Furthermore, prior application regulation of international treaty included in the existing "Sea Traffic Safety Act"(Article 5) was deleted in the screening of the National Assembly. So, doubt about whether the Ordinary Practice of Seamen could be continuously applied according to the regulation of the international treaty, nevertheless not specified in domestic law, has been continuously raised. In this situation, recently Central Maritime Safety Tribunal changed precedent by applying of Article 96(3) of Maritime Safety Act without applying Ordinary Practice of Seamen in the Case No. 2015-001. Accordingly, this study intended to review propriety of precedent change and legal issue with the decision of Central Maritime Safety Tribunal excluding Ordinary Practice of Seamen for a collision between Sea-going Vessels and Vessels at anchor.

• Structural Engineering and Mechanics
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• v.52 no.3
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• pp.613-632
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• 2014

In the early design stage of ships, the two most important structural analyses are performed to identify the structural capacity and safety. The first step is called global strength analysis (longitudinal strength analysis or hull girder strength analysis) and the second step is local buckling analysis (stiffened panel strength analysis). This paper deals with the ultimate strength performance of Arctic Sea Route-going commercial ships considering the effect of low temperature. In this study, two types of structural analyses are performed in Arctic sea conditions. Three types of ship namely oil tanker, bulk carrier and container ship with four different sizes (in total 12 vessels) are tested in four low temperatures (-20, -40, -60 and $-800^{\circ}C$), which are based on the Arctic environment and room temperature ($20^{\circ}C$). The ultimate strength performance is analysed with ALPS/HULL progressive hull collapse analysis code for ship hulls, then ALPS/ULSAP supersize finite element method for stiffened panels. The obtained results are summarised in terms of temperature, vessel type, vessel size, loading type and other effects. The important insights and outcomes are documented.

• Journal of the Korean Professional Engineers Association
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• v.44 no.2
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• pp.43-45
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• 2011

Somalian pirates with the onset of civil war in the early 1990s have caused a threat to international transportation. Various international organizations including the International Maritime Organization and the World Food Program are concerned about this problem. The cost of shipping is increasing and food-aid shipment is hindered by these ships are needed military escort. Since 2008, international society has deployed multinational naval vessel in the nearby Somalian sea and strengthen multinational naval operations to minimize damages from piracy.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.110-118
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• 2015

Weather routing method is one of the best practices of SEEMP (Ship Energy Efficiency Management Plan) for fuel-efficient operation of ship. KR is carrying out a basic research for development of the weather routing algorithm and making a monitoring system by FOC (Fuel Oil Consumption) analysis compared to the reference, which is the great circle route. The added resistances applied global sea/weather data can be calculated using ship data, and the results can be corrected to ship motions. The global sea/weather data such as significant wave height, ocean current and wind data can be used to calculate the added resistances. The reference route in a usual navigation is the great circle route, which is the shortest distance route. The global sea/weather data can be divided into grids, and the nearest grid data from a ship's position can be used to apply a ocean going vessel's sea conditions. Powell method is used as an optimized routing technique to minimize FOC considered sea/weather conditions, and FOC result can be compared with the great circle route result.

• Journal of the Korean Institute of Navigation
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• v.15 no.4
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• pp.1-11
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• 1991

Since it is very important for an ocean-going vessel to transmit information quickly and accurately to her owner or charterer not only for the ship's safety but for economic operation of the ship, some newly-built automated vessels equipped with automatic information transmission system which consists of INMARSAT-C and specially-designed computer. This system, however, is not applicable to the existing vessel without chaging her equipments and, furthermore, is too expensive for small shipping companies to fit out such a system on their vessels. Therefore, we propose a low-priced information transmission system which consists of a personal computer and communication equipments in the existing vessel, and in this paper, as the groundwork of the proposed system, we have made up the ship's position transmission system which is composed of and IBM AT-compatible, PC, INMARSAT-A and a GPS receiver. As the test result of the system through sea trial on the training ship 'HANBADA', we confirmed that transmission of the ship's position was achieved succesfully and consequently there could be high possibility of cost-effectiveness of the proposed system.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.359-364
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• 2004

When sea going vessel approaches her destination port, marine traffic density is increased, especially, the marine traffic is concentrated in the entrance channel and the fairway in the inner harbour is more narrow. Therefore, special navigational rules for preventing collision at sea is needed in the inner harbour. Hence there are the rules in The Public Order in Open Port Act in Korea But, in the case of conflict of navigational rule concerned, it is possible to be raised a question that which rule shall be applied preferentially. Also, it is necessary to understand the exact meaning of the navigational rules in The Public Order in Open Port Act. Because the misunderstanding of the rule is caused the collision Therefore, this paper aims to discuss the exact meaning of the navigational rule concerned in the view of legal basis and suggest the principles for a proper application of it.

• Ocean Systems Engineering
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• v.8 no.3
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• pp.313-327
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• 2018

Meeting the touchdown point (TDP) target box is one of the challenges during catenary riser installation, especially for deep water or ultra-deep water riser systems. TDP location mismatch compared to the design can result in variation of riser configuration, additional hang-off misalignment, and extra bending loads going into the hang-off porch. A good understanding of the key installation parameters can help to minimize this mismatch, and ensure that the riser global response meets the design criteria. This paper focuses on investigating the potential factors that may affect the touchdown point location, and addressing the challenges both in the design stage and during installation campaign. Conventionally, the vessel offset and current are the most critical factors which may affect the TDP movement during installation. With the offshore exploration going deeper and deeper in the sea (up to 10,000ft), other sources such as the seabed slope and seabed soil stiffness are playing an important role as well. The impacts of potential sources are quantified through case studies for steel catenary riser (SCR) and lazy wave steel catenary riser (LWSCR) in deep water application. Investigations through both theoretical study and numerical validation are carried out. Furthermore, design recommendations are provided during execution phase for the TDP mismatch condition to ensure the integrity of the riser system.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.306-311
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• 2015

Recently, vessel hijacking by pirates has been a big issue around the world. In case of the hostages of M/V "SAMHO Jewelry" on January 20, 2011, the Korean Navy has rescued 21 seafarers by first naval operation with somalia pirates since establishment of the Navy. Also, in case of the "HANJIN Tianjin", all crews evacuated to the Citadel promptly when being attacking by pirates and were safely rescued by the navy. By the accident, Necessity of Citadel for seafarer on board ship came to the fore against pirates. Taking in account increasing pirates accident at sea, many research relating to pirates has been implementing with a view to responding to them so far. By amending the ship facility regulation in the domestic law on Jan. 2011, the installment of Citadel on board ship became mandatory for ocean going vessel serving pirates area. Hence, this paper provides new model of Citadel structure based on an Fire Dynamic simulation in order to improve personal safety in case of vessel hijacking.