A.The marine sextant B.The chronometer C.The echo sounder D.The radar
单项选择题()sends a radio signal from the bottom of the ship to the sea-bed,from which it is reflected.
单项选择题()is the navigational timekeeper of the vessel.
A.The marine sextant B.The chronometer C.The magnetic compass D.The gyrocompass
单项选择题()is used for measuring horizontal and vertical angles.
A.The marine sextant B.Thechronometer C.The magnetic compass D.The gyrocompass
单项选择题()means rudder to be held in the force and aft angles.
A.Steady B.Meet her C.Midships D.Stop engines
单项选择题()means check the swing of the vessel’s head in a turn.