• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.207-212
• /
• 2003

Recently there has been a remarkable increase in the number of high speed and large ships, and the high power involved for propulsion of above ships have brought high pitch ratio and high skew propeller. The recent tendency toward highly skewed propeller has increased the load on propeller blades and the fatigue strength of propeller blades has become the critical point in design of propellers for above ships. In this paper fatigue tests in sea water were carried out on propeller material of Ni-Al bronze. The stress and environmental conditions of the test were selected to be close to those of full size propellers in use. The effect of stress ratio, stress frequency, revolution number of propeller for above ships numbers and so on were discussed.

• Journal of Navigation and Port Research
• /
• v.28 no.2
• /
• pp.113-119
• /
• 2004

Ships' collision accident has often occurred in congested waterways or in harbour areas. To examine the cause of collision accident may be necessary to prevention against another similar one. We discuss the construction of ship-manoeuvring-simulator system used for reproducing ships' collision phenomenon The system consists of one simulator bridge for own ship and two control consoles for own ship and target ship. Own ship and target ship are linked each other, and are simultaneously manoeuvred in simulator bridge or at control console respectively. And a simulator experiment for reproducing ships' collision phenomenon and for examining the cause of accident is carried out. Through the present case study, we find out that the constructed simulator system is very useful for reproducing ships' collision phenomenon and for examining the cause of accident.

• Journal of Ocean Engineering and Technology
• /
• v.30 no.4
• /
• pp.287-293
• /
• 2016

This paper presents an effective damage detection method for offshore jackets using natural frequency change ratios. Two parameters, cosine similarity and magnitude index, are considered to estimate the location and severity of the damage in the structure. A numerical jacket structure model is considered to verify the performance of the proposed method. As observed through analysis, the damages in the structure are detected accurately.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2019.05a
• /
• pp.228-229
• /
• 2019

Autonomous Ships are emerging as a game changer that transform the paradigm in the traditional manufacturing-oriented shipbuilding and shipping industries of simple cargo transportation. Accordingly, this paper also introduced detailed plans to develop the autonomous ships and to promote innovative growth engines.

• Journal of Ship and Ocean Technology
• /
• v.4 no.4
• /
• pp.34-44
• /
• 2000

This paper deals with the sea trial results of a fast craft with the hybrid supported type hul form. waterjet propulsion system and motion control system. The hybrid-type container ship operable in the sea with a wave height of y6 m, a speed of 50 knots and a payload of 1,500 tons were designed. A 1/8 scale 10 m- long test craft was constructed and tested in open seas. The hydrodynamic performance such as speed, turning, motion control in waves and waterjet thrush was analyzed.

• Journal of the Korean Institute of Navigation
• /
• v.13 no.3
• /
• pp.37-44
• /
• 1989

Recently recognize the labor productivity of port physical distribution system in the port and shipping areas, Much Efforts for evaluating this productivity has been made continuously. BUt still there is little study, so far, on a systematic research for the management of port labor gangs, and even those were mainly depended on a rule of thumb. Especially the object of this study is to introduce the method of optimal allocation and assignment for the labor gangs per pier unit in the multiple ships berthed at an arbitary pier or port. In case the multiple ships have a homogeneous cargoes or do not have sufficient labor gangs to be assigned. The problem of optimal allocation and assignment of the labor gangs to be i) formalized with multi-state decision process in form of difference equation as the pattern which converted the independent multiple ships into a single ship with the intra-multiple ships, and ii) the optimal size of labor gangs could be obtained through the simple mathematical method instead of complicated dynamic programming, and iii) In case of shortage of labor gangs available the evaluation function considering the labor gangs available and total shift times was introduced, and iv) the optimal allocation and assignment of labor gangs was dealt at the point of minimizing the summation of the total shift times and at the point of minimizing the total cost charged for the extra waiting time except PHI time during port times for the multiple ships combinations.

• Journal of Navigation and Port Research
• /
• v.27 no.3
• /
• pp.247-252
• /
• 2003

This paper is mainly concerned with the assessment of safe navigation between ships moving each other in restricted waterways. The numerical simulation of manoeuvring motion was conducted parametrically to propose an appropriate safe speed and distance, which is required to avoid sea accident under the different conditions, such as ship-velocity ratios, ship-length ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference between two ships were considered as 0.6, 1.2, 1.5 and the ones of ship-length difference were regarded were regarded as 0.5, 1.0, 1.18. From the inspection of this investigation, it indicates the following result. Firstly, the separation between ships is more needed for the small vessel, compared to the large vessel. Secondly, the lateral distance between ships is necessarily required for the velocity ration of 1.2, compared to the cases of 0.6 and 1.5. The manoeuvring characteristics based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in confined water.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.2
• /
• pp.236-244
• /
• 2014

Although a safety assessment of damaged ships, which considers environmental conditions such as waves and wind, is important in both the design and operation phases of ships, in Korea, rules or guidelines to conduct such assessments are not yet developed. However, NATO and European maritime societies have developed guidelines for a safety assessment. Therefore, it is required to develop rules or guidelines for safety assessments such as the Naval Ship Code (NSC) of NATO. Before the safety assessment of a damaged ship can be performed, the available damage scenarios must be developed and the safety assessment criteria must be established. In this paper, the parameters related to damage by accidents are identified and categorized when developing damage scenarios. The need for damage safety assessment criteria is discussed, and an example is presented. In addition, a concept and specifications for the DB-based supporting system, which is used in the operation phases, are proposed.

• Corrosion Science and Technology
• /
• v.10 no.3
• /
• pp.101-107
• /
• 2011

Marine ships have played an important role as a carrier, transporting much more than 80% of all international trading, and marine transportation is an internationally competitive, strategic, and great national important industry. However, those marine ships have the characteristics such as voyage of long distance, large-volume and lower speed than the other carry system. Therefore, it is important to manufacture a larger and faster ship, however, the steel plates which are consisted with most of those ships has brought about many corrosion problems in sea water such as general corrosion, localized corrosion, cavitation and erosion corrosion etc.. Most hulls of the ships have been protected with paintings, sacrificial anode, marine growth prevention system, and impressed current cathodic protection methods against numerious corrosion problems mentioned above. However, these conventional methods are not very effective because the rudder of ships stern are exposed to very severe corrosive environment such as tides, speeds of ships, cavitations and erosion corrosion, etc.. In this study, electrochemical and cavitation characteristics was investigated for the rudder material of ship which is exposed to serious corrosive environment. As a result, it is considered that the optimum cathodic protection potentials of rudder material is the range of -0.6 V ~ -0.8 V(Ag/AgCl) in static seawater.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.8
• /
• pp.1035-1040
• /
• 2011

In this study, many researches have been carried out against Energy Efficiency Operational Indicator(EEOI) of existing ships under discussion by IMO. This research is examined the method for the polices about IMO's greenhouse gas reducing emissions among them, we were analyzed the EEOI for existing ships. we have analyzed the result about applying EEOI using the calculation method of the rate of fuel consumption for cargo quantities to the actual existing ships and raised the problem. Based on this research, we were presented the improved EEOI about the engine load using fuel consumption and applied the existing ships. As a result, we concluded that the improved EEOI can define a resonable rate of $CO_2$ emissions.