The research vessel NARA equipped with an azimuth thruster system was built in 2015. There are few vessels with this propulsion system in Korea. This vessel has two modes such as the normal for maneuvering and the power for investigation, and the other two modes as one axis and two axes on the operating. This type of vessels does not seem to have a clear grasp of the maneuvering character in comparison with the vessel with a conventional propulsion system. So the authors carried out the sea test for the turning, the zigzag and the inclination, and the results are as follows. In turning test, the case of using the two axes mode is much better than the case of using the one axis mode for the elements of turning, such as advance, transfer, tactical diameter and final diameter, but turning hard over the rudder in full speed is very vulnerable to capsize in both modes. In zigzag test, the yaw quicking responsibility index,  is very large excessively, which means a bad counter maneuvering ability, so an operator has to keep in mind that in turning operation. If necessary to avoid collision at head on situation, it may be a more effective method to use the crash astern stop than the turning according to the conditions and circumstances for the shortest stopping distance is very short.

A historical tragic disaster happened by capsizing the passenger ship Sewol at South Western Sea of Korea in 16, April 2014. The ship which left Incheon harbour to bound for Jeju port passed Maengol strait and reached to approach of Byung Pung island, and then capsized and sank with a sudden inclination to the portside in the mean time of starboard the helm. In this time, the ship which has very poor stability without sufficient ballast waters and with over loading cargo listed port side caused by the centrifugal force acting to the outside of turning. A lot of cargoes not fastened moved to the port side consequently, and the ship came to beam end to capsize and sank in the end. No crews including especially captain would offer their own duties in a such extremely urgent time, as a result, enormous number of victims broke out including a lot of student. In this report, author carried out some calculation on the factors which influenced on the stability of the ship, i.e. the ship's speed, the rudder angle, the weight of cargoes and distance of movement, the surface effect of liquid in the tank. We found out that the most causes of capsize were the poor stability with heavy cargoes and insufficient amount of ballast water against the rule, and the cargoes unfastened moved one side to add the inclination as well. Above all, the owner be blamable because of the illegally operating the ship without keeping the rule.

Fishing vessels have been causing more than 70% of marine casualty in Korea. As a view of the occurring number of marine casualty, it is obvious for fishing vessel to account for the absolute high portion of that in comparison with the non-fishing vessels. That is a natural outcome because fishing vessels have occupied more than 90% of all registered Korean vessels. If we consider it not occurring number, but occurring ratio, we could find out that fishing vessels accounted for 5 times lower than non-fishing vessels in marine casualties. Nevertheless, fishing vessels have not immunity from responsibility for marine casualties at all, because the tendency of it in fishing vessel has been dominating the whole marine casualties in Korea. So for reduction of them, it is indispensable to decrease the casualties of fishing vessel. In this study, the authors tried to carry out many items of them to compare the occurring number with the occurring ratio, and dealt with the casualties of collision and machine damage in detail, because those have not only been occurring most frequently in casualties in Korea, but also led to the death and injury of lives. To reduce the collision and the machine damage, the operator have to keep the watch more strictly and check and keep the machine in good order. And it is necessary for the operator to take more education and training intended to decrease those systematically and continuously, especially for the crews of fishing vessels.

본 연구는 3년(2005. 12. 1-2008. 11. 30) 동안 부산의 PM2.5 대기오염자동관측소(장림동: 공업지역, 좌동: 주거지역) 측정자료 중 고농도 PM2.5(24시간 환경기준 50μg/m3)에 대한 PM2.5 및 PM2.5/PM10 농도비의 일변화 특성과 함께 시 공간적 풍계(풍향 및 풍속)에 따른 특성을 분석하고자 하였다. 고농도 PM2.5는 장림동과 좌동 각각 182일 및 27일이었다. 장림동에서 고농도 PM2.5의 시간평균농도 및 PM2.5/PM10 농도비의 일변화는 모든 계절에서 오후에 비해 새벽과 오전 및 야간에 높은 비슷한 패턴을 나타내었다. 좌동의 여름 주간에 PM2.5/PM10 농도비가 증가하는 것은 해양조건에서 광화학반응에 의해 생성되는 이차 입자상물질 중 PM10의 거대입자 농도가 미세입자인 PM2.5 농도보다 더 감소하기 때문이다. 시간대별로 시 공간적 풍계(풍향 및 풍속등급) 특성을 분석하였다. 그 결과, 고농도 PM2.5는 장림동에서 공업단지의 산업활동에 의한 오염물질 정체와 주변지역의 오염물질 이동에 의해 발생되었다. 좌동에서는 주로 주거와 상업활동으로 인한 지역적 오염물질 정체로 발생하는 것으로 나타났다.

The inherent efficiency of a ship would be prior to any other quality factors in ship's safety, because lack of it may give rise to a serious sea casuality even if it were a light mistake in operation. And the representative casualty comes from a deficiency of stability and an operating error combined would be capsizing. The Korean offshore large purseiner looks to have a structural weak point with small range of stability in spite of her big initial metacentric height, and have various type of roll reduction devices in order to cover up the defect. The aim of this study is to grasp for the roll reduction characteristics of the purseiner with bilge keel only and a stern keel additionally attached. The results are summarized as follows; The rolling angle of the model ship was increased in accordance with increase of the wave period and height, especially at close to the natural wave period of her, and the trends were more distinguished in the situation of bilge keel only installation than in the stern keel additionally installed. And stern keel has not noticeable effect on the reduction of the roll in the light ship condition, but has a little effect in full load condition.

Marine casualties of vessel are said to be in most case caused by human error, but it would be valid for the assumption that the ship is built with high quality and then should be acceptable to the safety standards. It means that the inherent characteristics of a ship should be the first consideration on the safety of ship. Therefore it is basically necessary for navigator to grasp the inherent stability of his ship and ensure that the ship complies with the minimum statutory standards of stability. This study is to realize the stability of the Korean offshore large purseiner varying with loading conditions by the inclining data and some calculations. The author compared the stability of the ship with IMO criteria and domestic rule, and proposed some improvement for the safety of the ship. The results are summarized as follows ; The values of GM of the ship according to the loading condition in navigation satisfy both of the IMO criteria and the domestic rule, but in case of the area under the GZ curves between the heel angles of 30˚ and 40˚, and the heel angle occuring the maximum righting lever not satisfy the IMO rule at the fishing ground departure and arrival conditions in the haul in net situation. The initial metacentric height of the ship is very large, but the range of stability and the occurring angle of the maximum GZ are very small, so even small inclining can bring about the beam end. The best method of improvement for that is to increase the freeboard of the model among the variables.

For the safety and cost reduction in the navigation, the automatic and intelligent system has been developed for the vessel, and the most important factor in the system is to decide the collision risk exactly. In this paper, we propose an advanced collision risk decision system for collision avoidance of the system. The conventional researches using DCPA and TCPA for calculating the collision risk have a problem to produce a same collision risk regardless of bearings for the ships, if they are located in the same distance from own ship. To solve this problem, in addition to DCPA and TCPA, we introduce the factor of VCD(variation of compass degree) and constant, CR which derived from COLREG'72(International Regulation for Preventing Collision at Sea, 1972) for evaluating the collision risk including even the burden of own ship navigator due to the encountering angle of each vessels. We decided the collision risk legally by the rule considering the relative situation of vessels. And therefore, the proposed system has two advantages, of which one is to produce more detail collision risk and another is to reflect the real underway situation in conformity with the rule.

Marine casualties of fishing vessels were analyzed to reduce the sacrifice of human life using data of the Korean Maritime Safety Tribunal from 1995 to 2004 in Korea. The occurred number of fishing vessel casualties were likely to be higher portion than non-fishing vessels, but the occurring ratio of fishing vessel casualties were marked 2.96 times lower than that of non-fishing vessel casualties. The occurring ratios of bigger fishing vessel casualties were higher than smaller ones. Most marine casualties were resulted from the human factors such as poor watchkeeping, negligent action for engine and etc. The trend of marine casualties showed that the machinery damage hold the first and collision accidents took the second, but on a point of cause of them, operating errors took first and poor handling or inspection of machinery held the second place. Because those two casualties took major portion, and very important problems for safety of fishing vessels, so we ought to try to reduce the factors before everything else. In addition, since collision, sinking and capsizing in marine casualties have led to death, missing and injury of lives, it is necessary for navigation operators to take more educations and training intended to reduce the marine casualties systematically and continuously.

Marine casualties of vessel are serious problems on social and national aspects, because it results in sacrifice of lives, a great lose of properties and marine pollution. According to recent statistics of marine casualties of vessel, fishing boats are more likely to be ended in the casualty, and especially, small fishing boats cause much more accidents than any other big vessels. Most of marine casualties were caused by the human factors such as poor watch keeping, inadequate manoeuvering and negligent action for engine, etc. This study is intended to provide navigator of small fishing boat with a specific information of necessary to assist both the manoeuvering and the avoidance of capsizing. The manoeuvering characteristics of ship can be adequately judged by the results of typical ship trials manoeuvres. For this purpose, the author measured the roll responses of a small fishing boat in waves using the real sea experimental measuring system, and analyzed the experimental data by the statistical and spectral analyzing methods to get the characteristics of the roll motion responses of the small boat through the wave directions and the ship's speed.

To investigate the fishery and fishing ground environment of red horsehead (Branchiostegus japonicus), the author analyzed the fishery data and examined the amount of catches and oceanic environment on the adjacent seas of Jeju island and East China Sea. It was turned out that the favourable season of the red horsehead fishery is the month from March to June, the main fishing ground is located in 60 mile radius from the position 32.5˚N, 125.7˚E. The bottom seawater temperature in fishing ground was shown between l3℃ and 16℃, the salinity was appeared between 33.5 and 34.0psu without the seasonal variation of the year. Concentrations of materials(e.g, NO3- and NO2-) in spring and summer time in main fishing ground were higher than any other seasons, but that of phospheric materials were lower than any other seasons. Concentrations of chlorophyll - α in the main fishing ground was the highest in spring and summer at the surface layer, but the vertical profile of the chlorophyll - α concentrations in all seasons were not variable at bottom layer. Mean density of zooplankton abundance according to the vertical structure was higher and much stable in summer and autumn than spring and winter.

This study is intended to provide navigator with specific information necessary to assist in the avoidance of collision and in operation of ships to evaluate the manoeuvrability of own ship. The actual manoeuvering characteristics of ship can be adequately judged from the results of typical ship trials manoeuvres. Author carried out sea trials based full scale for turning test, zig-zag test, spiral tests and crash-stop test at actual sea going condition. The turning circle manoeuvres were performed on starboard and port sides with 35˚ rudder angle at the service speed, and Zig-zag procedures were performed on both sides with 10˚ and 20˚ rudder angle respectively. Spiral tests were carried out on the both sides and crash stop test was also carried out. The results from tests could be compared directly with the standards of manoeuverability of IMO and consequently the manoeuvring qualities of the ship is fully satisfied with its.

실해상 실험을 통하여 해상의 조건이 동일할 때, 예망과 항해중일 때의 만남파에 대한 소형 트롤어선의 종동요와 횡동요의 응답특성을 통계적 방법과 이론적인 방법을 이용하여 분석하였다. 그 결과를 요약하면 다음과 같다. (1) 종동요의 응답 크기를 예망중과 항해중에 따라 비교하면 큰 차이가 없으나, 선수쪽에서 파를 받을 경우에는 항해중의 응답이 예망중 보다 양각 커지는 경향이 있다. (2) 횡동요의 응답은 예망중과 항해중 모두 종동요에 비해 매우 크다. 그러한 경향은 모든파향에서 현저하지만, 횡파를 받을 경우에는 양자의 응답 차이는 줄어든다. (3) 예망중과 항해중 모두 종동요에서 응답스펙트럼의 peak가 나타나는 주기는 파향에 관계없이 거의 일정하다. (4) 선미쪽에서 파를 받고 예망할 때, 양현에 균등하게 warp의 힘이 작용한다면, 어구의 저항은 동요를 감쇄시키는 상당한 효과가 있다.

This paper deals with an experimental study on the dynamical characteristics of ship motion during trawling job on the real sea. The experiments were carried out on the small stern trawler, and roll and pitch motion of the ship according to the wave directions were simultaneously recorded by P/C in the same sea conditions. From these data, the statistical properties and power spectra were obtained, and then the analysis of ship motion in trwal job was made. As a result, it was found that the pitch motions in trwal job were displayed low amplitudes on the whole, but the rolling motions were displayed high amplitudes relatively, and very high value on the beam and quartering sea especially. Also, the trial ship has a high extinction coefficient in the roll motion, compared with the rule of stability, but when wave height takes 2.5m over, it can induce the safety of ship to scare occasionally. Therefore, a usefull countermeasure for the safety of ship has to be made adequately.

부산수산대학교 해양탐사선 탐양호(GT : 653.0tons)의 조종성능을 파악하기 위하여 Z 시험을 행한 결과를 요약하면 다음과 같다. 1. 타각 10˚, 20˚, 30˚의 Z시험에서 방향성 지수 K'는 각각 0.9464, 0.8651, 0.8349이고, 방향성은 타각 10˚일 때가 추종성은 타각 20˚일 때가 좋으며, 대체적으로 대타각을 사용 할 때보다도 소타각을 사용 할 때의 조종성이 더 양호함을 알 수 있다. 2. Over shoot angle은 타각 10˚, 20˚, 30˚일 때 우현전타했을 때는 각각 14.3˚, 32.3˚, 52.1˚이고, 좌현전타했을 때는 14.5˚, 33.5˚, 53.3˚이며, 우현전타 할 때가 좌현전타 할 때보다도 조종성이 더 양호한 경향을 나타냈다. 3. 타각 10˚Z 시험에서 - 조작간 항주거리는 배 길이의 8.8배가되어 조종성표준거리인 5~11배 이내가 되므로 대체적으로 조종성능이 양호하다고 볼 수 있다.

1989년 11월 4~12일의 동지나해에서 관측한 자료를 사용하여 해황을 조사하였다. 그 결과 표층의 해황은 쓰시마 난류수와 중국 대륙 연안수로 대별되고 그 사이에는 강한 전선이 형성되고 있다. 쓰시마 난류수는 수온 22~24℃, 염분 33.5~34.5‰의 고온.고염수로 용존산소는 4.5ml/l 이하로 낮았다. 그리고 중국 대륙 연안수는 수온 18~20℃, 염분 32.0‰ 이하인 저온.저염수로 용존산소는 4.5~5.0ml/l로 높게 나타났다. 저층에도 역시 표층과 같이 쓰시마 난류수와 중국 대륙 연안수가 존재하였다. 이 외에도 북쪽에는 수온 10℃ 이하, 염분 33.0‰ 내외, 용존 산소는 4.5ml/l 이상의 고산소수인 황해 저층냉수가 분포하고, 동남쪽에는 수온 15~19℃ 염분 34.5‰, 용존산소는 2.0~3.5ml/l의 저산소수인 동지나해 남부 저층수도 분포하였다. 그리고 중국 대륙 연안수와 쓰시마 난류수의 중간 특성을 나타내는 수온 20.5~22.0℃, 염분 32.3~33.3‰의 물은 중국 대륙 연안수와 쓰시마 난류가 혼합된 결과라고 판단된다.