patent t log拖曳式计程仪
patent log detail拖曳计程仪
N（名词） any of several mechanical devices for measuring the speed of a vessel and the distance travelled, consisting typically of a trailing rotor that registers its rotations on a meter 拖曳式计程仪 ; 测量船只速度和行驶距离的机械仪器 [nautical] → compare chip log