单项选择题
A.Any time the vessel moves from water of one density into waters of a different density
B.Prior to getting underway when the vessel is floating in fresh or brackish water
C.Only when the vessel moves from fresh water into salt water
D.The density of the water is not required to be logged in the unofficial logbook
单项选择题 When are fore and aft draft readings required to be entered in the unofficial logbook of a ship? （）
单项选择题 When an azimuth of the Sun has been taken and the deviation of the standard magnetic compass computed，the watch officer should record the results（）.
单项选择题 When a vessel is entering or leaving a port，a record of engine speeds is kept in the（）.