In the actual sea, the additional resistance due to external force such as wind, current and wave is accompanied, and the required power is added in response to these resistance. Especially when the ship is sailing at low speed, the effects of wind and current have a great impact on the safe control of the ship. Likewise, it is thought that the effects of wind and current have a great impact on the trawl ship control since the towing speed of a bottom trawl ship is a low speed of 3 to 4 knots. If the reduce of ship speed and the increase of engine power due to the influence of wind and current can be identified, the safe towing power can be calculated based on a given engine output. Thus, the appropriate size of a fishing gear can be determined. In this study, a total of 20 trawl operations were conducted for seasonal maritime research in the same research area according to the operation mode of propeller. Based on navigation data, trawl fishing data, and engine performance data acquired during the towing fishing gear, and data of ship speed, hull resistance, fishing gear resistance, wind force and current force according to an incidence angle were estimated. The overall power for these loads was calculated and compared with the measured engine power, and the effects of wind force and current force on the engine power were investigated.

서 론
재료 및 방법
    실험에 사용된 선박 및 어구
    선체의 전저항과 유효마력의 산정
    외력에 의한 부가저항 산정
    예망시 항해자료 및 트롤어구 저항 측정
    기관운전(constant & combined mode) 및 출력 측정
결과 및 고찰
    모형선 시험 자료
    실선의 선체저항과 유효마력
    예망속력에 따른 선체저항 및 유효마력과 어구저항
    트롤조업 시의 부가저항 산출
    부가저항이 기관출력에 미치는 영향
결 론

• 왕우경(전남대학교 기관시스템공학과 교수) | Woo-Gyeong WANG (Professor, Department of Power System Engineering, Chonnam National University, Chonnam 59626, Korea) Corresponding Author