간행물

Journal of Korean Navigation and Port Reserch KCI 등재 한국항해항만학회지

권호리스트/논문검색
이 간행물 논문 검색

권호

Vol.12 No.2 (1988년 8월) 5

1.
1988.08 서비스 종료(열람 제한)
The transportations of most of cargoes in world trade have been fulfilled through sea lanes and it seems this trend will not change in near future. Nowadays, inview of the technical aspects of merchant vessels, they are continuously enlarged in hull size and greatly specialized in structure for the cargo spaces and dramatically automatized in navigating, piloting, cargo operating and various other operations, which unavoidably require high technicals in operating the modern merchant vessels. On the contrary to the trend of requiring of operating high technicals, the capabilities of crew on board have been gradually declining in technical competence and their morale for accomplishing their duties on board vessels has greatly falled won compared with that of old days. The above result inevitably brings many problems in operating modern vessels and causes accidents which are avoidable through good competence and high morale of the crew. We intend to analyze the causes of several great sea accident with which it seems some human errors are connected more or less directly or indirectly. We hope that this study could suggest some measures which help to prevent the recurrence of similar accidents by Korean ship's crews.
2.
1988.08 서비스 종료(열람 제한)
This paper offers a method of magnetic compass adjustment for the vessel alongside the wharf using newly designed magnetic north former, which makes the same magnetic field-change as the turning vessel does. The characteristics of the magnetic north former was examined by observing the deviation curves of the magnetic compass installed on the compass deviascop at laboratory. The magnetic north former consists of A and B arms which hold the permanent bar magnets at the both ends of each arm. The arm is to rotae in the horizontal plane about the vertical axis fixed at the center boss of the magnetic compass and it is to compensate the horizontal plane about the vertical axis fixed at the center boss of the magnetic compass and it is to compensate the horizontal component of the earth's field. The B arm makes the artificial magnetic north around the magnetic compass for every ship's heading. The results of investigation are summarized as follows ; 1. The observation and correction of magnetic compass deviation can be done without swinging the ship, of the effect of D coefficient is negligible. 2. The residual deviation curve of the magnetic compass depends on the accuracy of deduced value of ship's multplier(λ). 3. The errors due to the inaccuracy of deduced value of ship's multiplier change in the same way as the B and C coefficient do.
3.
1988.08 서비스 종료(열람 제한)
As a basic study for enhancing the sensitivity of the follow-up system of the marine gyrocompass, the geometric characteristics of the deflection sensor were investigated and the theoretical model of it was formulated. The output signal voltage of the deflection sensor was esamined by changing the attitude of gyrosphere against follow-up container. The characteristics of the output are found to be indentical with those of the distance difference versus the relative azimuthal deflection of the gyrosphere against the follow up container. On the base of the theoretical model, some useful points for the design of the deflection sensor are suggested as following : 1. When the difference between semidiamter of gyrophere and that of the follow-up container decreases, the sensitivity of deflection sensor increases. 2. If the semidiameter difference of two spheres is constant, the sensitivity of deflection sensor is proportional to the magnitude of the semidiamter of each sphere. 3. The farther the gyrosphere is deviated from the center of follow-up container, the higher the sensitivity of deflection sensor is. 4. It is recommendable that the value of the datum deflection of the electrodes on the gyrosphere should be within the range between 4˚ and 16˚deviated from north-south line.
4.
1988.08 서비스 종료(열람 제한)
The amount of cargoes and fishery production have increased continuously during the last decade due to the great growth of the Korean economy. These increasements have made our coastal traffic congested, and the future coastal traffic is also expected to increase considerably. The increased traffic can be a cause of large sea pollution as well a s greater sea casualties us as properties and human lives, which could result in a big national loss. In order to prevent the sea casualties and promote the safety of coastal traffic, the Vessel Traffic Management System (VTMS) along the Korean coastal waterway is inevitably introduced. But, the precise evaluation is necessary required prior to the implementation of VTMS because this system necessitates a huge amount of budgets. This paper aims to propose the model of evaluation process, but the evaluation as to the urgency of establishment is not only very complicated and fuzzy but also affected by the subjectivity of human. Therefore, fuzzy integral is adopted as the mathematical model of evaluation in which decision-maker can intervence by making decision considering the calculated membership-function. Four aspects, namely, the frequency of sea-casualities, the traffic volume, the frequency fuzzy day, and the complexity of waterway are selected as the item of evaluation, and the fuzzy measure are applied to the evaluation of 8 candidated regions such as the adjacent area to the port Inchen, Kunsan, Mokpo, Wando, Yosu, Pusan, Pohang, Donghae. As a result of evaluation, the priority as to the candidated regions is obtained, and the following prior execution regions, namely, the adjacent area to the port Pusan, Yosu, Mokpo & Wando are selected by considering the present situation, but, in the long run, the VTMS should be executed in the whole coast of the nation, through the cost-effectiveness analysis.
5.
1988.08 서비스 종료(열람 제한)
In spite of the widespread use of stiffend plates in ship structures, it is very difficult to analysis these directly. So, in conventional analysis of plate structures, above structures are used to be idealized as orthotropic plate or grillage structures. Lately, the development of large computers, it is able to apply the optimum techniques to structural design. In this paper, the double bottom structure of Bulk Carrier was idealized into flat grillage which is composed of intersecting beam stiffencers primarily loaded mormal to its surface. And strength analysis was carried out by using the finite element method based on displacement. And further, according to variation of floor space and double tobbon heightm, the optimum design was carrid out by using Hooke and Jeeves direct search method.