간행물

Journal of Korean Navigation and Port Reserch KCI 등재 한국항해항만학회지

권호리스트/논문검색
이 간행물 논문 검색

권호

Vol.10 No.2 (1986년 11월) 8

1.
1986.11 서비스 종료(열람 제한)
For the purpose of estimation of navigational method and ability about fishing raft, we have practical navigation of her from Chujado on Oct, 7 to Maryang-ri , Kangjin-kun, Jeonranman-do on Oct.10. The results obtained are as follow : 1. Ancient navigation of her is thought to over to an isolated island in the vicinity with a good informations and experiences. 2. Speed of her in outward voyage is 1.34 knots, but is varied with structure and shape of her and ability of fishing raftman. 3. The lee way(U) of her with sail of hight 2.5m and breadth about 1.2m according to windspeed(W) is U=0.038×W 4. We could estimate to take only three days to go over from Chujado to Maryang-ri, Kangjin-kun. Jeonranam-do by her with sail, and make a voyage total 55 miles for thirty-four hours and ten minutes i, e, mean speed is 1.6knots resulty.
2.
1986.11 서비스 종료(열람 제한)
As per the expanding needs of marine exploitation, many floating structures have been built. Among these, box-type vessel is considered as the most basic shape, to which plant barges and crane barges belong. Stability problem is very important for vessel. In order to increase transverse stability, this paper employs bulwarks along the upper deck sides of box-type vessels and the emphasis is laid upon the effect of bulwarks on transverse stability. In the present paper, the calculation method of heeling moment acting to the ship due to hydrostatic pressure is suggested, and actual procedures of the calculation for box-type vessels with bulwarks are shown. Furthermore corresponding model tests are carried out in small water tank. Through the comparison between calculated and measured values, it is confirmed that the preset calculation method is useful. And employing bulwarks on box-type vessels is very effective for increase of transverse stability at the heeling angles from about 15 degrees to about degrees.
3.
1986.11 서비스 종료(열람 제한)
Generally, the development of shipping is characterized by the amount of traffic flow (traffic volume) and seaborne cargo in the sea. Movement of ships is an essential element of constructing the traffic flow which is represented the dynamic movement of ships in the sea, but on the other band the numbers of arriving and departing the port is the basic factor consisting of the static movement of ships. The amount of cargoes by coastal vessels and ocean trade vessels have increased tremendously with the great growth of the Korean economy these days. This increase of the seaborne cargoes has made the Korean coastal traffic flow so congested that this can be a cause of large pollution as well as great marine casualities such as a loss of human lives and properties . And also the future coastal traffic is expected to increase considerably according to our economic development and high dependence upon foreign trade. Under the circumstance, to devise the safety of coastal traffic flow and to take a proper step of a efficient navigation, there is a necessity for analyzing and surveying the coastal traffic trend and the characteristics of cargo movement. In order to grasp the dynamic movement of ships in the Korean coast, O/D analysis is executed. This paper aims to secure the basic data necessary for a comprehensive plan and estimation of vessel traffic management system for the enhancement of safety, order and efficiency of vessel traffic in the Korean coast. The analyzed results of the traffic flow and seaborne cargoes of the Korean coast are summarized as follows : 1) The congestion by the vessels occurred around the ports such as-in proportion of ship's number (proportion of tonnage) -Incheon 18.5%(14.8%), Pohang 5.9% (9.9%), Samil 5.2%(8.3%), Mokpo 8.6%(0.8%), Pusan 13.5%(36.4%), Ulsan 9.1%(16.2%). 2) It is found that the area adjacent to Incheon, Pusan, Ulsan, Channel of Hanryu and South-western area are heavily congested. 3) It is confirmed thatthe area adjacent to Incheon, Pusan, Ulsan, Channel of Hanryu and South-western area are heavily congested. 3) It is confirmed that the coastal vessels are main elements constituting the coastal traffic and that there are much traffic flow among five ports as following through the precise O/D analysis of ship's coastal movement. Incheon-Samil, Ulsan, Pusan, Jeju Pusan -Samil, Ulsan, Incheon, Jeju Pohang -Samil, Inchoen, Jeju Pohang -Samil, Incheon, Jeju Ulsan -Samil, Incheon, Jeju Samil -Ulsan, Pusan, Incheon 4) The amount of cargoes to abroad are in proportion about 81% of total and the amount of coastal cargoes are about 19%. Of those, cargoes in and out to Japan are about 26% and to South-east Asia are about 27%. 5) The chief items of foreign cargoes are oil(38.33%), iron ore(13.98%), bituminoous coal(12.74%), grain(8.02%), lumber(6.45%) in the import cargoes and steel material(21.96%), cement(17.16%), oil(6.81%), fertilizer(3.80%) in the export cargoes. 6) The 80.5% of total export cargoes and 92.4% of total import cargoes are flowed in five main ports. 7) The chief items of coastal cargoes are oil (42.45%), cement(16.86%), steel material (6.49%), anthracite(6.31%), mineral product(4.3%), grain, and fertilizer. Almost 92.24% of total import and export oil cargoes in Korea is loaded and unloaded at the port of Samil & Ulsan.
4.
1986.11 서비스 종료(열람 제한)
The conventional school affairs management, with an example of Korea Martitime University (KMU), is studied through the university codes and its internal regulations and the inevitable problems of the conventional school affairs are analyzed. From the view points of complexity of the educational structure and increase in educational population, the computerized school affairs management is increasingly requested. Therefore, in order to design and implement a computerized school affairs management system, a code-system suitable for the KMU is, first of all, constructed and then a data base which copes with various reforms or changes is developed by using the code system and the IMAGE/DMBS of a HP-9040AM computer. A FORTRAN example program shows that the designed data base can be easily transformed into on-line system and made good use of managing school affairs. Furthermore, it is recommended that the university authority organize a research team for designing the total system in future university administration and solving difficult problems occurring through the computerization.
5.
1986.11 서비스 종료(열람 제한)
In the restricted sea way such as fair way in harbor, narrow channel etc, the safe ship-handling is a very important problem, which is greatly related with turning ability of ships. It is of great importance that ship-handlers can grasp the position of pivoting point varying with time increase at any moment for relevant steering activities. Mean while, in advanced ship-building countries they study and investigated pivoting point related with turning characteristics, hut their main interest lies in ship design, not in safe ship controlling and maneuvering. In this regards it is the purpose of this paper to provide ship-handlers better under standing of pivoting point location together with turning characteristics and then to help them in safe ship-handling by presenting fact that pivoting points vary according to configuration of ships. The author calculated the variation of pivoting point as per time increase for various type of vessels, based on the hydrodynamic derivatives obtained at test of Davidson Laboratory of Stevens Institutes of Technology , New Jersey, U.S.A. The results were classified and investigated according to the magnitude of block coefficient , length-beam ratio, length-draft ratio, rudder area ratio ete, and undermentioned results were obtained. (1) The trajectory of pivoting point due to variation of rudder angle are all the same at any time, though the magenitude of turning circle are changed variously. (2) The moving of pivoting point is affected by the magnitude of block coefficient, length-beam ratio, length-draft ratio, however the effect by rudder area ratio might be disregarded. (3) In controlling and maneuvering of vessels in harbor, ship-handlers might regard that the pivoting point would be placed on 0.2~0.3L forward from center of gravity at initial stage. (4) The pivoting point of VLCC or container feeder vessels which have block coefficient more than 0.8 and length-beam ratio less than 6.5 are located on or over bow in the steady turning. (5) When a vessel intends to avoid some floating obstruction such as buoy forward around her eourse, the ship-handler might consider that the pivoting point would be close by bow in ballast condition and cloase by center of gravity in full-loaded condition.
6.
1986.11 서비스 종료(열람 제한)
Ship's maneuverability is very important factor in safe ship handling and economical ship operation. Steering characteristics are consisted of course stability and maneuverability. Today in many advanced ship-building countries, they study ship's course stability, using model ship tests, such as straight line tests, rotating arm tests and Planar Motion Mechanism (PMM) etc., in tow in tanks. It is the purpose of this paper to provide ship's handlers with better understanding of steering characteristics and to help them in safe controlling and manevering . In this paper, the author simulated response of various vessels, running straight course with constant speed, and they are disturbed by small external disturbance of one degree yaw angle with no angular velocity . The author used the hydrodynamic derivtives resulted at tests of Davidson's laboratory in Stevens Institute of Technology, New Jersey, U.S.A. Course stability was evaluated and analyzed in various respects, such as block coefficient, ratio of ship's length to beam, draft and rudder area ratio etc. The obtained results are as follows : (1) The ship's course stability is affected by magnitude of block coefficient greatly. In case that the block coefficient is more than 0.7, the deviation varies at nearly same rate but the requistite time to reach the steady course is different. (2) The ship's course stability is affected by magnitude of L/B. When the dimensionless time reaches about 3, the deviation and requisite time to reach the steady course are influenced nearly same. After the dimensionless time is about 3, they change on invariable ratio. (3) The effect to course stability by L/T and RA' can be neglected. (4) The reason why thy VLCC and container feeder vessel are unstable on their course is that their block coefficient is generally more than 0.8 and the ratio of ship's length to beam is about 6.0.
7.
1986.11 서비스 종료(열람 제한)
The purpose of this study was to explore the nature of the relationship between several factors representing the mental health enumerated in the psychology literature and the dadaptability to group life which all of th KMU students encounter. An empirical study was carried out to examine not only the differences in mental health of 4 kinds of students groups but also the impact of interaction which mental health affects to the adaptability to group life among grades. The several factors of the mental health can be utilized in suggesting the theoretical bases for the countermeasures of the effective group life along with the motivation of KMU students. The data investigating the impact of interaction between mental health and the adaptability to group life were collected from 537 KMU students selected from 4 different kinds of population-(1) Freshman group (2) Sophomore group (3) Junior group (4) Senior group-by the use of questionnaire method and interview. The 2-way analysis of variance (MANOVA) were used to analyze the data. The results of this study were found as follows; (1) There are significant difference in the cognition of gloom, personal sensitiveness, anagonism, anxiety and total score among 4 grade groups, (2) The freshmen group and the sophomore group have perceived gloom, personal sensitiveness, antagonism, and total score more acutely than the junior group and senior group have. (3) There are significant differences in perceiving an obession and personal sensitiveness according to the adaptation types to the group life; adaopted type, non-adapted type. The non-adapted group has recognized an obsession and personal sensitiveness more seriously than the adapted group has. (4) The interaction between grades and the adaptation status doesn't have an direct influence on the mental health.
8.
1986.11 서비스 종료(열람 제한)
In this paper the dynamic effects due to the free water motions in tanks upon the lateral motion of a floating body in regular waves are calculated, in order to obtain the relationship between a motion of a floating body and that of the free water in tanks. Under the assumption that the fluid is ideal and motion amplitudes are small, velocity potential of the fluid in tanks is calculated by the source distribution method and the hydrodynamic forces and moments are calculated by the integration of fluid pressures over the tank surface. Hydrodynamic effects of the fluid on the floating body are expressed in terms of added mass and coupling coefficient obtained from the integration. Computations are carried out for ship with seven wide center tanks and comparisons between the liquid cargo loading case and the rigid cargo loading case are shown.