单项选择题
A Doppler log in the volume reverberation mode indicates（）.
A.speed being made good B.speed through the water C.the set of the current D.the depth of the water
单项选择题 A Doppler speed log indicates speed over ground（）.
单项选择题 A double male coupling is one that（）.
单项选择题 A fairly accurate estimation of a ship’s position can be calculated by a technique known as（）.
