You are using a radar in which your own ship is shown at the center，and the heading flash always points to 0°. If bearings are measured in relation to the flash，what type of bearings are produced? （）

单项选择题You are underway in thick fog. You have not determined if risk of collision exists. Which statement is TRUE?（）.

A.Your speed must be reduced to bare steerageway
B.A look-out is not required if the radar is on
C.Fog signals are only required when a vessel is detected by radar
D.The radar should always be kept on a short-range scale

单项选择题You are underway in restricted visibility and hear a fog signal forward of the beam. Nothing appears on your radar screen. You must（）.

A.stop your engines
B.sound two prolonged blasts of the whistle
C.sound the danger signal
D.slow to bare steerageway

单项选择题You are underway at 5 knots and see on your radar a contact 10 miles directly astern of you. 12 minutes later，the contact is 8 miles directly astern of you. What is the estimated speed of the contact? （）

A.Dead in the water
B.1 knot
C.10 knots
D.15 knots

单项选择题You are scanning the radar screen for a buoy fitted with racon. How should this signal appear on the PPI display?（）

A.Starting with a dash and extending radially outward from the target
B.As a broken line from center of PPI to the target
C.Starting with a dot and extending radially inward from the target
D.Starting with a dash and extending to the right of the target

单项选择题Which statement is true concerning a vessel equipped with operational radar?（）.

A.The Master of the vessel must be on the bridge when the radar is in use
B.The radar equipment is only required to be used in restricted visibility
C.The use of a radar excuses a vessel from the need of a look-out
D.This equipment must be used to obtain early warning of risk of collision