A rigid replica of the International Code flag “A” may be shown by a vessel （）.

单项选择题A report of casualty to a mobile offshore drilling unit must include （）.

A.the estimated cost of damage to the unit
B.an evaluation of who was at fault
C.the amount of ballast on board
D.the name of the owner or agent of the unit

单项选择题A report of casualty to a mobile offshore drilling unit must be made in writing to which office? （）

A.Commandant of the Coast Guard
B.Owner of the unit
C.Nearest Coast Guard Marine Safety Office
D.Captain of the nearest port

单项选择题A red triangular daymark marks （）.

A.the centerline of a navigable channel
B.the starboard side of a channel
C.a prominent object of navigational interest that has no lateral significance
D.an area of a channel where passing another vessel is permitted

单项选择题A rapid rise or fall of the barometer indicates（）.

A.heavy rain within six hours
B.a decrease in wind velocity
C.a change in the present weather conditions
D.that fog will soon set in

单项选择题A radar range to a small，charted object such as a light will provide a line of position in which form? （）

A.Straight line
B.Arc
C.Parabola
D.Hyperbola