• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.107-116
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• 2022

Local management trade ports are small-sized trade ports, which require active operation to strengthen the local cities' economic power and enhance the local industries' added value. In addition, local management trade ports should berth ships larger than the existing ships to increase efficiency and keep up with the international trend where ships are becoming larger. Furthermore, they should also prepare operating standards. This study selected Okgye Port among local management trade ports. We performed a mooring safety simulation evaluation according to the scenario where a 50,000 DWT vessel is moored at the current 20,000 DWT class pier. The emergency departure criteria were 27kts at 3.2s of wave period and 22kts at 5.0s of wave period at the existing pier. Results showed that mooring limit condition increased by about 50% to 41kts at 3.2s of wave period and 36kts at 5.0s of wave period. This study can be used for strengthening mooring facilities and setting operational standards for safe port operation when large ships are berthing.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.946-954
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• 2022

More than half of barges have been surveyed and designated as an "unmanned barge". The main advantage of the unmanned barge is that it can carry more cargo equivalent to 25 percent of freeboard compared to that of a manned barge. In contrast, it needs an onboard crew barge because the bargeman is in charge of several tasks during sailing such as mooring or unmooring barges to or from a wharf, dropping and heaving up an anchor and turning on and of navigational lights and shapes. The instant recognition is that a tug assume the responsibility of operating a barge; however, different situations exist in which the shipper, as the operator of the barge, hires a tug. Although a tug might be a carrier of a barge under a specific contract, the master of the tug should fulfill his duty to complete its voyage. Most masters are not provided with the particulars of a barge and the information regarding the bargemen onboard, which is believed not to respect the master's authority and lead to an unintended violation of relevant laws. This paper presents three recommendations for resolving these issues: the policy approach for changing unmanned barges to manned barges, issuing a minimum safe manning certificate, and providing the master of tug information on the barge and the crew onboard. Thus, the proposed approach can be expected to improve the crew's working conditions, diminish the violation of the maximum number of persons onboard the barge, and ensure the authority of the master of tug through such recommendations.

• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.18-25
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• 2022

MOF strengthen the law and institutions for safety management after the capsize accident of passenger ship "Sewol" on April 16, 2014. Nevertheless, about 13 cases of marine accidents such as collisions, contact, and stranding have occurred in coastal passenger ships over the past 5 years. Particularly, according to the judgment of KMST, most of the main causes of passenger ship accidents occurred within harbor areas because of the master's improper ship-handling or inattention. And so, this study analyzed four cases of marine accidents on passenger ships that occurred in the port areas and examined the environmental, institutional, material, and human factors that contributed to the master's improper ship-handling and behavior, and the results are as follows. First, as an environmental factor, the size of the turning basin was not enough. Second, as an institutional factor, the VTS control was not properly supported, the master lacked sufficient training for safe ship-handling in the port area and up-to-date charts were not provided. Third, as a material factor, the digital type speed log capable of the ship's speed in real-time was not installed on the ship's wing bridge. Lastly, as a human factor, the master could not take proper bridge resources and the passage plan was not proper. Therefore, it is suggested in this paper that the size of the turning basin should be adjusted to meet the prescribed standards, the master of passenger ships should receive the ship-handling simulation training among other safety training to ensure safe ship-handling of the master in the port area as improvement measures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3B
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• pp.311-319
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• 2006

A bed level change model(SED-FLUX) is introduced based on the realistic sediment transport process including bed load and suspended load behaviours at the bottom boundary layer. The model SED-FLUX includes wave module, hydrodynamic module and sediment transport and diffusion module that calculate suspended sediment concentration, net sediment erosion flux($Q_s$) and bed load flux. Bed load transport rate is evaluated by the van Rijn's TRANSPOR program which has been verified in wave-current fields. The net sediment erosion flux($Q_s$) at the bottom is evaluated as a source/sink term in the numerical sediment diffusion model where the suspended sediment concentration becomes a verification parameter of the $Q_s$. Bed level change module calculates a bed level change amount(${\Delta}h_{i,j}$) and updates a bed level. For the model verification the limit depth of the bed load transport is compared with the field experiment data and some formula on the threshold depth for the bed load movement by waves and currents. This model is applied to the beach profile changes by waves, then the model shows a clear erosion and accumulation profile according to the incident wave characteristics. Finally the beach evolution by waves and wave-induced currents behind the offshore breakwater is calculated, where the model shows a tombolo formation in the landward area of the breakwater.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.857-862
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• 2023

In order for an autonomous ship to arrive near the pier and automatically berth without the help of a tugboat or pilot, it is necessary to recognize the pier and calculate the thruster output and output angle for berthing to the pier at a fixed berthing speed under given external force conditions. Therefore, in this study, the external force and moment acting on the ship while berthing were analyzed, and the thruster output calculation for automatic berthing was designed and the basic concept for the development of the automatic berthing program was designed. The wind pressure applied to the hull by the wind while the ship is berthing was calculated based on the wind pressure area and the wind direction angle and the turning moment to rotate the ship according to the transverse force of the ship was calculated. Considering the force acting on the ship and the turning moment during berthing, a theoretical formula was presented to calculate the thruster output and output angle for berthing parallel to the pier, and the turning due to other variables was controlled by the PID controller. In addition, the basic concept for program development was presented by analyzing the input elements necessary for the theoretical formula.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.209-216
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• 2024

Four accidents occurred between 2020 and 2022 after car ferries built according to a coastal passenger ship modernization plan collided with other ships or came into contact with the dock when entering Jeju Port. Accidents primarily occurred owing to careless ship handling and drift by wind during ship handled by herself using bow and stern thrusters without tugboats. Accordingly, in this study, we analyzed the collision accident focusing on car ferry H and the critical wind speed at which the ship cannot be controlled using its own power, tugboat operation plan in increasing wind speed were proposed based on the power required for the ship to berth parallel to the pier without a tugboat considering the external force and moment generated while the ship is berthing. A analysis of the critical wind speed of car ferry H by relative wind direction when using tugboats or not according to the loading status and the berthing speed, showed that one tugboat should be used at the stern when the lateral wind speed is over 10 m/s and two tugboats should be used when the lateral wind speed is over 14m/s berthing at Jeju port.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.157-164
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• 2024

In 2020, 24,000 TEU ultra-large container ships began arriving at the Busan New Port. In this study, the wind pressure and hydraulic force acting on the hull were calculated to obtain the horsepower required for the tugboats for safe berthing and unberthing of a 24,000 TEU ultra-large container ship at the Busan New Port. When the wind speed is 10 m/s (20 kts), 13,000 TEU container ships meet the tug horsepower standard of the current Busan port tugboat operation rules, but 16,000 TEU and 24,000 TEU container ships do not satisfy the regulations. Therefore, it was proposed to raise the standards for tugboat use by dividing the size of ships of "G/T 150,000 tons or more," which is the largest vessel under the current tugboat use standards, into two stages. Because 140,000 tons requires 12,100 horsepower, 170,000 tons requires 14,500 horsepower, and 230,000 tons requires 18,000 horsepower, the study proposed 16,000 horsepower for 150,000 to less than 200,000 tons and 18,000 horsepower for 200,000 tons or more for the use of tugboats.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.832-859
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• 2011

The importance of scientific education on accurate oceanic currents and circulation has been increasingly addressed because the currents have played a significant role in climate change and global energy balance. The objectives of this study are to analyze errors of the oceanic current maps in the textbooks, to discuss a variety of error sources, to suggest how to produce a unified oceanic current map of the East Sea for the students. Twenty-seven textbooks based on the 7th National Curriculum were analyzed and quantitatively investigated on the characteristics of the current maps by comparing with both the previous literature and up-to-date scientific knowledge. All the maps in the textbooks with different mappings were converted to digitalized image data with Mercator mapping using geolocation information. Detailed analysis were performed to investigate the patterns of the Tsushima Warm Current (TWC) in the Korea Strait, to examine how closely the nearshore branch of the TWC flows along the Japanese coast, to scrutinize the features of the offshore branch of the TWC south of the subpolar front in the East Sea, to quantitatively investigate the northern range of the northward-propagating East Korea Warm Current and its latitude turning to the east, and lastly to examine the outflow of the TWC near the Tsugaru Strait and the Soya Strait. In addition, the origins, southern limits, and distances from the coast of the Liman Current and the North Korea Cold Current were analyzed. Other erroneous expressions of the currents in the textbooks were presented. These analyses revealed the problems in the present current maps of the textbooks, which might lead the students to misconception. This study also addressed a necessity in a bridge between scientists with up-to-date scientific results and educators who needed educational materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.226-244
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• 1998

The relationship between the transport of eggs and larvae of Anchovy (Engraulis japonica) and the oceanic condition in the southern sea of Korea was examined on August and November 1996. In summer (August), when the Tsushima Warm Current is strong near to the coast, the warm waters such as warm streamers from the Tsushima Warm Current intrude into the coastal area, and cyclonic circulations are formed. The warm water intrusions also generate wakes around Komun Island, Sori Island and Koje Island. In the coastal area where the warm water intrusions occur, the nutrients, dissolved oxygen, suspended solid and chlorophyll are concentrated in probably relation to the upwelling concerned with this warm streamer and/or the wakes. Anchovy eggs and larvae are transported to the coastal area by the cyclonic circulations. The hatching and growth of anchovy larvae are increased because of high primary production in the cyclonic circulations. However, as the amount of Copepods which are a main food for anchovy larvae decrease in the coastal area, anchovy larvae seem to move to the Isushima Warm Water area for seeking a prey. In autumn (November), the Tsushima Warm Current is far away from the coast. In this season the warm water intrusions almost disappear, and the small scaled frontal eddies are formed between the coastal water and the Tsushima Warm Water. As the surface water moves towards offshore, few anchovy eggs and larvae were sampled in the survey area. Chemical and biological substances are concentrated in the leftdown sides of the small scaled frontal eddies because of eddy formation.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.4
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• pp.36-48
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• 2010

The objectives of this study are to research and analyze the positioning of Mt. Back Hwa(白華山) and the characteristics of its neighboring cultural scenery based on the Two Seated Buddah Temple, a small Buddhist temple of Taeul in Taean and to view both landscape geographic codes and religious attractions over Mt. Back Hwa by discussing its expression and meaning for the scenery scattered or nested over this districts. The panoramic view of west shows the character of Mt. Back Hwa as a magnanimity of Buddhist Goddess of Mercy which is viewed as a view point field no less than its location as a landscape target and its singularity as a rocky mountain. The ancient castle, signal beacon post and the small Buddhist temple of Taeul to be read importantly in the old map and SinjeungDongkukyeojiseungram(新增東國輿地勝覽) form the core of place identity, and a number of carve(engrave) letters such as Eopungdae(御風臺), Youngsadae(永思臺), etc. show the prospect of this mountain and monumentality derived from place characteristics. In addition removing of Taeiljeon, a portrait scroll of Dangun, national ancestor makes possible to guess the national status hold by Mt. Back Hwa in advance and to know that it has symbiotic relationship with indigenous religion and shares with the universal locality which have been continued for a long time through a portrait scroll of Dangun enshrined in Samsunggak. More than anything else, however the Rock-carved Buddha Triad in Taean, Giant Buddha of Baekjae era enshrined in the small Buddhist temple of Taeul is not only why Mt. Back Hwa, magnanimity of Buddhist Goddess of Mercy exists but also a signifier. In spite of such a placity, the union ideas of confucianism, buddhism and doctrinism of buddhism prevailed in the Late Joseon Dynasty allows the cultural phenomenon of taoism to be read in the same weight through Ilsogae(一笑溪) and Gammodae(感慕臺) which are mountain stream and pond area respectively centered in the carve letter, 'Taeeuldongcheon(太乙洞天)' constructed in front of the small Buddhist temple of Taeul, the Baduk board type of rock carvings engraved over them and a number of traces of carve letters made by confucian scholars since the Middle of Joseon Dynasty. The reason such various cultural sceneries are mixed in Mt. Back Hwa is in the results of inheritance of religious places and fusion of sprit of the times, and the various type of cultural scenery elements scattered in Mt. Back Hwa are deemed as unique geographic code to understand the multi-layered placity and the characteristics of scenery of Mt. Back Hwa in Taean.