• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.3
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• pp.640-653
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• 2015

In order to develop the challenging process of placing Aids to Navigation (AtoN), we propose performance measures which quantifies the effect of such placement. The best placement of AtoNs is that from which the navigator can best recognize the information provided by an AtoN. The visibility of AtoNs depends mostly on light sources, the weather condition and the position of the navigator. Visual recognition is enabled by achieving adequate contrast between the AtoN light source and background light. Therefore, the performance measures can be formulated through the amount of differences between these two lights. For simplification, this approach is based on the values of the human factor suggested by International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA). Performance measures for AtoN placement can be evaluated through AtoN Simulator, which has been being developed by KIOST/KRISO in Korea and has been launched by Korea National Research Program. Simulations for evaluation are carried out at waterway in Busan port in Korea.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.4
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• pp.294-300
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• 2017

The offshore installations and ships are the structures most likely to be exposed to hazards such as hydrocarbon fire and/or explosion. Developing proactive measures to prevent the escalation of such events thus requires detailed knowledge of the related phenomena and their consequences. $CO_2$ extinguishing systems are extensively used for fire accidents of on-and offshore installations because of outstanding performance and low cost. There is, however, the risk of carbon dioxide system which enumerates many of the fatalities by suffocation associated with industrial fire protection requirements. Therefore, the aim of this study is to perform the prediction of fire suppression characteristics of the carbon dioxide system in realistic enclosed compartment area of ships and propose $CO_2$ extinguish fire fighting system for preventing suffocation accidents during fire fighting. According to CFD calculations, it can be observed and assessed that various fire profiles with $CO_2$ and $O_2$ mole fraction in the target enclosed compartment area are applicable within the proposed system. Additionally, the design of fire safety system of ships and offshore installations can utilize ventilation system and/or layout arrangement through the proposed system.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.6
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• pp.407-414
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• 2021

The manoeuvrability of a ship with an unwanted heel angle due to a maritime accident is changed from the original characteristics. The purpose of this study is to quantitatively investigate the change in the manoeuvring performance of a twin-screw ship under various hee angles and speed conditions. A series of free running model test campaigns were performed in the Ocean Engineering Basin of Korea Research Institute of Ships & Ocean Engineering (KRISO) for a twin-screw car ferry vessel. Turning circle test and zig-zag 10/10 and 20/20 tests were carried out on the heel angles of 0, -10, and -19.5 degrees. In addition, two-speed conditions were considered to understand the effect of ship speed. In order to examine the effect of the bilge keel, a heel angle of -22 degree where the bilge keel is exposed outside the water surface, was considered. Finally, the change of manoeuvring characteristics according to the heel angle for a twin-screw and a single-screw vessel is discussed.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.1
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• pp.9-17
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• 2022

In this paper, wind load on a semi-submersible rig was investigated using Computational Fluid Dynamics (CFD). A maritime atmospheric boundary layer model for wind profile was implemented such that the wind profile shapes were retained throughout the computational domain. Wind load on the semi-submersible rig was calculated under the maritime atmospheric boundary layer and matched well with the results from wind tunnel test within a ±20% error. Overturning moments with variation of draft were investigated by decomposing into drag and lift components. It was observed that the contribution from lift to the overturning moments increased as the draft got higher. The majority of the lift components originated from deckbox which served as a lifting body due to the accelerated streamlines between waterline and the bottom of the deckbox.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.6
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• pp.53-59
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• 2021

The ROK Navy operates many war ships despite its short history. Various types of war ships, such as submarines, destroyers, frigates, corvette etc., use suitable propulsion systems for the operational requirements of each war ship. A hybrid propulsion system was introduced to change from the current mechanical propulsion system to an electric propulsion system according to the changing patterns of naval warfare, and it is expected that an integrated electric propulsion system will also be introduced. Therefore, this paper investigates the propulsion system of major ships operated by the Korean Navy, predicts the changes in future naval warfare, and proposes a propulsion system for future ships.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.6
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• pp.416-423
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• 2023

Recently, the design point of the propeller is gradually changing due to the demand for energy saving and environmental protection. Until recently, self-propulsion model tests were conducted using stock propellers and geometry information was provided to propeller designers, but the range of existing stock propellers did not keep up with the changing design points, and the range of series propellers required in the initial design was also insufficient. Future propeller performance requires high performance and eco-friendliness, and the need for expansion of series propellers has increased. In order to respond to future needs and provide a wide range of advantages in propeller design, KRISO manufactures about 100 series propellers and builds series data through a model tests. In this paper, the approach method for deriving the representative optimal shape to be applied to the 4-blade series propeller in the initial stage of series propeller development was summarized.

• Journal of Ocean Engineering and Technology
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• v.37 no.5
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• pp.205-214
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• 2023

As the regulations on greenhouse gas emissions at sea become strict, efforts are being made to minimize environmental pollutants emitted from fossil fuels used by ships. Considering the large sizes of ships in conjunction with securing stable supplies of environment-friendly energy, interest in nuclear energy to power ships has been increasing. In this study, the neutron irradiation that occurs during the nuclear reactor operation and its effect on the structural responses of the stiffened-plate structures are investigated. This is done by changing the material properties of DH36 steel according to the research findings on the neutron-irradiated steels and then performing the structural response analyses of the structures using analytical and finite-element numerical solutions. Results reveal the influence of neutron irradiation on the structural responses of the structures. It is shown that both the strength and stiffness of the structures are affected by the neutron-irradiation phenomenon as their maximum flexural stress and deflection are increased with the increase in the amount of neutron irradiation. This implies that strength and stiffness need to be considered in the design of ships equipped with marine nuclear reactors.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.6
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• pp.490-500
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• 2011

The paradigm that ships are navigated by means of analog navigation devices and caption's experiences is shifted to that ships can be navigated by digital and autonomous navigation systems due to the rapid development of electronics and communication technologies. Hence, all systems deployed in a ship are automated and integrated since corresponding ship systems are not individually operated but integrated and managed under common operating system. In this paper, we overview recent research projects targeted for digitally integrated ships (referred to as digital ships), outline IEC 61162 series, specifying digital interface standards for digital ships, and finally present several issues for further improvement of the IEC 61162 series. In addition, we broadly categorize digital ships into three systems consisting of multiple sub-systems, including a navigation system, a power system, and a automation system in the aspect of operation and function. Corresponding interfacing range and method, as well as interface specification and data types of one system in a digital ship are also described according to sub-systems, respectively.

• Journal of Ocean Engineering and Technology
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• v.5 no.2
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• pp.191-191
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• 1991

• Bulletin of the Society of Naval Architects of Korea
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• v.8 no.1
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• pp.119-127
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• 1971

This paper attempts an educated guess at developments in world-wide needs for ocean commerce. It tries to predict the kinds of new ships that will be needed between now and the year 2000. It considers the requirements for competitive shipbuilding and suggests various steps that Korean shipbuilders may to take in order or capture an enlarged share of the world's shipbuilding business.