A.Dead reckoning positionB.Leeway positionC.Estimated p……

单项选择题Which of the following are data layer categories to be displayed on ECDIS（）．

A.ECDIS warnings and messages
B.Hydrographic Office data
C.Notice to Mariners information
D.All of the above

单项选择题Which buoy will NOT display white retro reflective material（）.

A.Safe water mark
B.Isolated danger mark
C.Preferred channel mark
D.Daymark of no lateral significance

单项选择题When using horizontal sextant angles of three objects to fix your position，an indeterminate position will result in which situation（）.

A.The objects lie in a straight line
B.The vessel is inside of a triangle formed by the objects
C.The vessel is outside of a triangle formed by the objects
D.A circle will pass through your position and the three objects

单项选择题When navigating a vessel，you（）.

A.Can always rely on a buoy to be on station
B.Can always rely on a buoy to show proper light characteristics
C.Should assume a wreck buoy is directly over the wreck
D.Should never rely on a floating aid to maintain its exact position

单项选择题When latitude and longitude are used，these shall be expressed in（）（and decimals of a minute if necessary），north or south of the Equator and east or west of Greenwich.

A.Fathoms and meters
B.Miles and kilometers
C.Arc and degrees
D.Degrees and minutes