Trawl fishing is a fishing method in which a large, motorized trawler tows a bag-shaped net to catch fish living at the bottom or middle layers. For a trawl gear, it is of utmost importance to select the gear size and towing speed suitable for the effective horsepower (EHP) of the trawler in the design stage. In general, the power required to move an object is proportional to the product of the object speed and resistance; therefore, there are various choices for the gear resistance and towing speed given the effective horsepower of the trawler. However, there have been few studies on the gear design of an appropriate scale for the towing speed given the effective horsepower of the trawler. In this study, the resistance and shape of three types of midwater trawl gears were analyzed using SimuTrawl, a computer simulation tool. In addition, the relationship between the propulsion force and speed of the ship was clarified when the size and effective horsepower of the trawler were determined. Finally, we suggested the relationship between the towing speed and the resistance of the gear when the trawler towed the net was investigated, and a specific method of selecting the gear size according to the towing speed.

This study is designed to measure the impact of a car’s horse power and torque - aspects related to performance among various factors that affect consumer purchase decision-on consumers when buying a car. The research of the results can be interpreted as indicating that the premise, “The impact of torque and horsepower on consumer purchase decision is not significant,” is true.

사고선박의 2차적인 피해를 줄이기 위해서는 사고선박을 안전한 곳으로 이동시키기 위한 예인선의 소요마력 산출이 요구되며, 길이 93 m 여객선형 대상선박에 대한 실선실험을 통하여 소요마력 산출에 대한 이론적인 계산식의 유효성을 검증하였다. 실선실험 결과는 이론계산 결과와 비교해 볼 때 상당히 일치되어 예선의 소요마력 산정을 위해 사용하기에 충분하다고 판단되며, 정적저항에서 공기저항, 마찰저항, 잉여저항과 더불어 프로펠러 고착저항이 상대적으로 큰 값으로 평가되었다. 피예인선은 예인과정에서 좌우 측면으로 30°정도까지 스윙운동 및 요우잉이 발생하였으며, 이로 인한 동적저항이 큰 값으로 평가되었다. 추후 안전율에 대한 연구가 필요할 것으로 판단되며, 저항의 정확한 예측을 통하여 안전율을 최소화함으로써 경제적인 예인선의 사용이 가능할 것으로 판단된다.

In order to estimate the effective horse power(EHP) in towing net of a bottom trawl ship, the ship's resistance was calculated by using a series data of Yamagata and Wigley formula. Also the effective horse power for a ship(EHPs) was estimated versus the ship speed in sailing and the propulsive efficiency was calculated with the brake horse power and the effective horse power. Then the effective horse power for a ship and a trawl net were estimated in the application of the propulsive efficiency in towing net. The total effective horse power(EHPT) was average 187.6kW and the effective horse power for a 1.awl net(EHPn) was average 176.7kW at a smooth sea state in towing net. The ratio of EHPn to EHPT was about 94.0% and the value was higher slightly than was already informed at a smooth sea state. The power for keeping up a townet speed was required more about 20% of a maximum continuous power at a rather rough sea state than a smooth sea state. In the future, if the residual resistance is considered with a sea state, EHPn will be estimated more correctly Also the data of EHP estimated by this method will be used as the basic data to design a trawl net.

The existing fisheries managers ignored the fishery environment changes, have built competitively vessels of efficiency superiority with related corporations, and have captured indisciminately fisheries resourecs. The economical engine horsepower selection model for fishing vessels shorter than 24m is developed. Also, the economical engine horsepower selection model system is verified by the existing vessels, and the optimum vessel scale and engine horsepower classified by the type of fishery and scale are proposed.

모형저항시험 자료를 토대로 선형요소들에 대한 통계 회귀계수를 만들고, 이를 이용하여 새로운 어선의 기본설계 단계에서 유효마력을 추정할 수 있는 방법을 정립하였다. 이러한 방법을 Chine Line이 있는 소형 표준어선 4척과 Round Bottom형 표준어선 2척에 적용하여 유효마력을 추정하였으며, 이를 실험값과 비교하였다. 이 6척 어선의 경우 전속도 범위에서 추정치와 실험치가 잘 일치하고 있는 것과 근접한 것으로 나타났다. 그러므로 작성된 수치계산법은 어선의 유효마력추정에 매우 유용하게 쓰일 수 있음이 입증되었다. 따라서 제안된 방법을 어선설계에 적용하면, 직접적으로는 저항성능을 개선할 수 있을 뿐 아니라, 설계공수단축, 원가절감 등에 기여할 수 있을 것이다.

From the results of model tests, statistical regression analysis for EHP estimation based on hull form parameters is adopted in this study. From this result, the method for estimation of EHP and optimization of hull form parameters at the initial design stage of fishing boats is developed. This method is applied to two standard fishing boats with chine lines. The EHP s are estimated and compared to experimental results. From the optimization of four principal hull form parameters of these fishing boats, approximately 19% of resistance reduction at the design speed is achieved and thus certifies that this method can be used efficiently for the initial design of hull forms of fishing boats.

Authors studied the propulsion efficiency of G. T. 280 to 300 class tuna longliners used in Korea. At first authors calculated the ratios and factors of the ship by use of principal dimensions. In cordance with this ratios and factors authors, examined the effective horse power, propulsion ficiency and brake horse power, and following results are obtained. (1) EHP is slightly increased according to the increasing of Froude number and speed. (2) Value of propulsion coefficient is obtained in the range of 51-54% at the cruising speed an its average is 52% in 6-13 knot of the speed. (3) EHP and BHP are increased according to the increasing of prismatic coefficient at the same speed.