The aging fishery training vessels from the past have mostly been decommissioned, and many universities are introducing state-of-the-art large fishery training vessels. The purpose of these training vessels is to train marine professionals and above all, safety to prevent marine accidents should be of utmost priority as many students embark on the vessel. This study estimated the impact of the hydrodynamic interaction forces acting on the model vessel (fishery training vessel) from the bank when the vessel pass near the semi-circle bank wall in various conditions through the numerical calculation, especially concerning maneuvering motions of the vessel. For estimation, variables were mainly set as the size of the semi-circle shape, the lateral distance between the bank and the model vessel, and the depth near the bank. As a result, it was estimated that, in order for the model vessel to safely pass the semi-circle bank wall at a speed of 4 knots, the water depth to the vessel draft ratio should be 1.5 or more (approximately 8 m of water depth), and the lateral distance from the semi-circle bank wall should be 0.4 times the model vessel’s length or more (a distance of 34 m or more). Under these conditions, it was expected that the model vessel would pass without significantly being affected by the bank wall.
In order to understand basic data for improving the fishing system and fishing vessel structure in coastal improved stow net fishery, a questionnaire survey and on-site hearing were conducted from May 10 to June 11, 2019 to analyze opinions on the improvement of operation status and fishing vessel structure. The questionnaire survey consisted of ten questions on the operation status of coastal improved stow net fishery and six questions on the improvement of fishing vessel structure, and the results of each question were analyzed by the region, the captain’s age, the captain’s career and the age of fishing vessel. As a result of analyzing opinions on the operation status of the coastal improved stow net fishery, it was found that the average time required for casting net was 32.8 to 33.0 minutes and that the average time required for hauling net was 41.0 to 42.2 minutes which took 10 to 12 minutes more than for casting net. The most important work requiring improvement during fishing operation (the first priority) were ‘hauling net operation,’ ‘readjustment and storage of fishing gear,’ and ‘fish handling’ and the hardest factor in fishing management were in the order of ‘reduction of catch,’ ‘labor shortage’ and ‘rising labor costs.’ The most institutional improvement that is most needed in coastal improved stow net fishery was an ‘using fine mesh nets.’ Most of the respondent to the questions on the experience in hiring foreign crews was ‘either hiring or willing to hire foreign crews,’ and the average number of foreign crews employed was found to be 2.3 to 2.4 persons. The most important reason for hiring (or considering employment) foreign crews was ‘high labor costs.’ The degree of communication with foreign crews during fishing operation were ‘moderate’ or ‘difficult to direct work.’ The most important problem in hiring foreign crews (the first priority) was an ‘illegal departure.’ As the survey results on the opinion of structural improvement of coastal improved stow net fishing vessel, the degree of satisfaction with fishing vessel structure related to fishing operation was found to be somewhat unsatisfactory, with an average of 3.3 points on a five-point scale. The inconvenient structure of fishing vessel in possession (the first priority), the space needed most for the construction of new fishing vessel (the first priority) and the space considered important for the construction of new fishing vessel (the first prioprity) was a ‘fish warehouse.’ The most preferred equipment for the construction of new fishing vessel were ‘engine operation monitoring’ and ‘navigation safety devices.’ The average size (tonnage class), the average horse power and the average total length of fishing vessel for proper profit and safety fishing operation was between 13.8 and 14.0 tonnes, 808.3 to 819.5 H.P. and 23.4 to 23.5 meters, respectively. The results of the operation status of coastal improved stow net fishery and the requirement for improving the fishing vessel structure are expected to be provided as basic data for reference when we build or improve the fishing vessel.
겨울철 한반도와 부근 해역은 대륙에서 발달하는 시베리아고기압과 해양에서 발달하는 알류샨저기압으로 형성되는 전형적인 서고동저형의 기압배치의 영향을 많이 받는다. 이 기압배치의 영향으로 우리나라와 주변 해역, 특히 서해에서는 강한 서풍 내지 북서풍의 계절풍과 강한 바람에 의한 높은 파랑, 폭설 등을 동반하는 악기상이 빈번히 발생한다. 이 연구에서는 겨울철에 서해에서 활동하는 국가어업지도선의 안전한 피항지를 선정하기 위하여 11년간 (1994-2004년)의 지상일기도를 분석하여 온대저기압의 주요 이동경로를 구분하였다. 그리고 온대저기압의 이동경로별로 섬들의 지형적 특성, 수심, 저질의 상대, 조류의 영향 및 어망의 분포 등을 조사하고, 그 결과를 이용하여 서해에서 활동하는 국가어업지도선의 안전한 피항지를 선정하였다.