• Journal of the Korean Institute of Navigation
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• v.10 no.2
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• pp.31-55
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• 1986

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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.30 no.1
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• pp.13-24
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• 1994

Purse seiner detects a fish school navigating in full speed with the aid of fish finder, sonar, helicopter, etc., and casts a net quickly to enclose the fish school in purse seine net according to the movement of the fish school, wind, and current. At this moment, if the time of casting a net, direction, speed, and turning circle are net suitable, it is unavoidable to lose fish school founded with hard efforts and we only consume our efforts of casting and hauling the net. Therefore, in order to enclose the fish school to enhance the amount of fish for each casting, the author investigated the type of ships equipped with purse seiners and examined maneuvering tests so that we provide some basic information to figure out the ability of steerage correctly. The results obtained are summarized as follows: 1. Block coefficients of pelagic tuna purse seiners with gross tonnage between 500 and 1500 tons are recorded between 0.50 and 0.55 which are greater than those of off shore purse seiners recorded as between 0.44 and 0.54 and less than those of various cargo ships recorded as between 0.56 and 0.84. 2. L/B, L/D, B/D, B/T, and T/D of the class of gross tonnage between 75 and 130 tons are respectively 4.49, 11.00, 2.45, 2.85 and 0.86 as their average and those of the class of between 500 and 1500 tons are 4.89, 10.53, 2.15, 2.73 and 0.75 respectively, which are quite different from those of various cargo ships recorded as 6.0~7.5, 11.0~12.0, 1.6~2.0, 2.2~2.8 and 0.65~0.75 respectively. 3. Rudder area ratio of purse seiners of the class of between 75 and 130 tons is 1/24~1/31 and that of the clase of between 500 and 1500 tons is 1/36~1/42 which is greater than that of various cargo ships recorded as 1.45~1.75. 4. On speed-length ratio of purse seiners. 111 Dong-a has the biggest value 2.94 the class of 130 tons has 2.52 the class of between 75 and 100 tons has 2.30~2.35 and the class of between 500 and 1500 tons has 1.99~2.05. 5. Turning circle of stern trawlers Pusan 404 and Haelim 3 are measured as below according to rudder angles 5$^{\circ}$, 15$^{\circ}$, 25$^{\circ}$ and 35$^{\circ}$ respectively. Advances are 11.3~13.6, 6.0~7.1, 3.6~4.8 and 2.5~3.5 times of LPP respectively. Tactial diameters are 15.2~18.6, 6.9~8.0, 4.2~4.9 and 2.9~3.5 times of LPP. Purse seiner 111 Dong-a with rudder angle 35$^{\circ}$ has a good yaw with quick responsibility since its advance is 2.2~2.3 times of LPP and since its tactial diameter is 2.0~2.1 times of LPP. 6. In full ahead going of purse seiner 111 Dong-a, it takes about 2 minutes and 10.6 times of LPP from the reverse turning its engine into full astern to the ship speed 0. In its full astern going, it takes about 1 minute and 5.1 times of LPP from the reverse turning its engine into full ahead to the ship speed 0. In its full ahead going, it takes about 2 minutes and 50 seconds and 12.3 times of LPP from stopping its engine to the dead slow ahead speed 3.2 knots.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.373-380
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• 2018

The small coastal vessel registered in Korea, small coastal vessels with a gross tonnage of 10 tons or less account for 94.6 % and among them, aged vessels over 16 years age indicate 40.6 %. In order to reduce GHG emissions from small coast vessels, discussions are underway to replace aging ships' propulsion units with eco - friendly propulsion facilities, and the electric propulsion ship is emerging as one of the measures. The electric propulsion system using the DFE rectifier, which was applied in the conventional large commercial vessel, was effective in reducing the harmonics and improving the DC output voltage of the DC link stage, but it occupied a large volume and caused an increase in the overall system price. Therefore, in this paper, we propose an electric propulsion system using AFE rectifier with a small volume of system that can be applied to a small coastal vessel. In order to analyze the effectiveness of the overall system, the load profile was applied to obtain accurate and rapid speed tracking performance of the propulsion motor affected by the speed load. In addition, the power factor and total harmonic distortion factor of the voltage and current on the improved power output side are derived through simulation.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.88-94
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• 2003

A series of tests of 5 model ships, selected from a data survey of 10 Gross Tonnage actual fishing boats, were performed in two circulating water channels (Chosun University in Korea and WJFEL in Japan), in order to develop the basic hull form of a 25 knots-class fishing boat. Resistance tests, trim and sinkage measurements and wave pattern observations etc., were included in each I1wdel test, and the model test results were compared and analyzed. The result was as follows: P-4 hull form ship changed into Deep V type bow is the best hull form with good performance, especially with regard to ship's resistance efficiency.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.257-264
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• 2015

This study is intended to provide navigator with specific information necessary to assist the avoidance of collision and the operation of ships to evaluate the maneuverability of dead weight tonnage 8,000 tons Oil/Chemical tanker. The actual maneuvering characteristics of ship can be adequately judged from the results of typical ship trials. Author carried out sea trials based full scale for turning test, Z" maneuvering test, man overboard rescue maneuver test, inertia stopping test. Consequently, $2^{st}$ Overshoot yaw angle of the semi balanced rudder and flap rudder in ${\pm}20^{\circ}$ zig-zag test showed $22.2^{\circ}$ and $18.0^{\circ}$, respectively. The maneuverability of the vessel was good in the flap rudder. The man overboard rescue maneuver maneuverability test was most favorable in the flap rudder and the full load condition. The results from tests could be compared directly with the standards of maneuverability of IMO and consequently the maneuvering qualities of the ship is full satisfied with its.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.245-256
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• 2015

This study is intended to provide navigator with specific information necessary to assist the avoidance of collision and the operation of ships to evaluate the maneuverability of dead weight tonnage 8,000 tons Oil/Chemical tanker. The actual maneuvering characteristics of ship can be adequately judged from the results of typical ship trials. Author carried out sea trials based full scale for turning test in ballast condition and full load condition, semi balanced rudder and flap rudder. The turning circle maneuvering were performed on the starboard and port sides with $35^{\circ}$ rudder angle at the normal continuous rating. The results from tests could be compared directly with the standards of maneuverability of IMO and consequently the maneuvering qualities of the ship is full satisfied with its.

• Journal of Navigation and Port Research
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• v.30 no.1 s.107
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• pp.9-15
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• 2006

At the adjacent sea area of Busan Central Wharf, a variety of vessels, such as middle-large passenger ships, small hugh speed crafts, container ships, cargo ships and working boats as well as small miscellaneous vessels are freely sailing comparatively without special rules and marine traffic control. In this research, we analyzed traffic stream and navigational characteristics cf main traffic route based on statistics and distribution of tracks by ship's type and tonnage cf the passing vessels after conducting marine traffic survey twice using exclusive software. We examined the traffic safety of the passing vessels by classifying the sea area by each function based on the analysis about this traffic situation, and analyzing the effect by designating 'Inner passage'. We also studied the plan for the effective rearrangement cf Central Wharf considering basically the traffic safety of arrival and departure in a point of view of navigators.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.706-714
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• 2020

Currently, 90 % of the world's population breathes air with a fine dust content exceeding the World Health Organization's annual average exposure limit (10 ㎍/㎥). Global efforts have been devoted toward reducing secondary pollutants and ultra-fine dust through regulations on nitrogen oxides released over land and sea. Domestic efforts have also aimed at creating clean marine environments by reducing sulfur emissions, which are the primary cause of dust accumulation in ships, through developing and distributing environment-friendly ships. Among the technologies for reducing harmful emissions from diesel engines, electrostatic precipitator offer several advantages such as a low pressure loss, high dust collection efficiency, and NOx removal and maintenance. This study aims to increase the durability of a ship by improving equipment quality through failure mode effects analysis for the preventive maintenance of an electrostatic precipitator that was developed for reducing fine dust particles emitted from the 2,427 kW marine diesel engines in ships with a gross tonnage of 999 tons. With regard to risk priority, failure mode 241 (poor dust capture efficiency) was the highest, with an RPN of 180. It was necessary to determine the high-risk failure mode in the collecting electrode and manage it intensively. This was caused by clearance defects, owing to vibrations and consequent pin loosening. Given that pin loosening is mainly caused by vibrations generated in the hull or equipment, it is necessary to manage the position of pin loosening.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.652-660
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• 2017

Recently, the number of tourists using cruise ships in Korea is increasing. and an big cruise ship with an gross tonnage of 160,000 tons or more has entered the domestic ports. Therefore, the government has been making a lot of efforts to confirm the cruise infrastructure for revitalization of the domestic cruise industry. However, there are no standards for cruise ship specifications and water facilities in the domestic port and fishery design standards. Currently, construction of dedicated cruise facilities is under way in major domestic ports. However, due to lack of specifications and domestic standards for cruise ships, it is difficult to design and license special facilities. Therefore, in this study, PIANC rule and domestic harbor and designing standard of fishing port were compared and analyzed in order to present the standard specification of cruise ships. And analyzed the representative linearity of cruises currently being operated. As a result of the ship characteristics analysis, There was a difference in coastal passenger ship in specifications and ship maneuverability. Therefore, in order to design facilities dedicated to cruising, the specifications of the target ship must be included in the domestic design standard. In addition, in order to calculate the scope of the target ship, I applied the coverage rate of 75% to the average specification value of the cruise ship and presented the standards of the cruise ship and the standard of the water area facilities.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.822-831
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• 2021

Although programs have been developed to evaluate the risk of dragging anchors, it is practically difficult for VTS(vessel traffic service) operators to calculate and evaluate these risks by obtaining input factors from anchored ships. Therefore, in this study, the gross tonnage (GT) that could be easily obtained from the ship by the VTS operators was set as an independent variable, and linear and nonlinear regression analyses were performed using the input factors as the dependent variables. From comparing the fit of the polynomial model (linear) and power series model (nonlinear), the power series model was evaluated to be more suitable for all input factors in the case of container ships and bulk carriers. However, in the case of tanker ships, the power supply model was suitable for the LBP(length between perpendiculars), width, and draft, and the polynomial model was evaluated to be more suitable for the front wind pressure area, weight of the anchor, equipment number, and height of the hawse pipe from the bottom of the ship. In addition, all other dependent variables, except for the front wind pressure area factor of the tanker ship, showed high degrees of fit with a coefficient of determination (R-squared value) of 0.7 or more. Therefore, among the input factors of the dragging anchor risk assessment program, all factors except the external force, seabed quality, water depth, and amount of anchor chain let out are automatically applied by the regression analysis model formula when only the GT of the ship is provided.