Competency II : Use of RADAR and ARPA to Maintain Safety of

Navigation
Function :1
Level : ANT-III

1. What are such areas known as target detection ranges are considerably reduced
due to shipboard structures like the samson posts etc ?
a. Shadow areas
b. Shadow sectors
c. Blind sectors
d. Blind areas

2. What is the meaning closest point approach ?

a. The closest two ships will pas each other if both ships maintain course
and speed
b. Two basic parameters needed two assess the risk of collision in meeting
situation at sea are passing
c. Range between three ships will pass each other if both ships maintain course
speed
d. Located at the bottom which take place within radar terminology

3. The targets echoes appear along line called ?

a. Heading marker
b. Scanner
c. Centre line
d. Timebase

4. What is function of the waueguide ?

a. Shape the beam in vertical plane
b. Block the transmitter during reception
c. Conduct pulses to and from the scanner
d. Generate the R.F Pulses

5. Why should ground stabilised true motion display mode be avoided when using
the arpa for Anti collision purposes. . . . .
a. The true vector can never give an indication of collision risk with another
ships
b. The collision regulations are based on ship courses through the water
c. The relative motion display and relative vectors is the only display to use
for anti-collision purposes
d. True motion does not provide the collision risk of other ships
6. The international nautical mile is ?
a. 1853 m
b. 185 m
c. 1852 m
d. 1,852 m

7. What the signal from a racon. . . . .

a. Only provides rang data
b. Enables the beacon to be identified
c. Does not provide identification
d. Only provides bearing data

8. The echo presentation have factors govern, what is the factors ?

a. Characteristic of the receiver
b. Characteristic of the transmitter
c. All of these
d. Characteristic of the display

9. The officer in charge of a navigational watch must ?

a. To be on the bridge when necessary
b. To attend the bridge or always be available for the call
c. Always be available for the call
d. Be physically present on the bridge

10. Which of these glues only a bearing and not a range ?

a. Lt vessel
b. Buoy
c. Racon
d. Ramark

11. What is the vertical beam must be wide enough to allow for. . . . .
a. The size of the large target
b. Elimination of shadow sectors
c. Rolling and pitching of the ship
d. Reduction of sea clutter

12. To carry out a trial maneuver, which of these input information is not required
.....
a. A delay
b. The proposed speed
c. The proposed course
d. The proposed position of the target
13. Unwanted radial lines that sometimes appear on the radar screen, the name
given is. . . . .
a. Ranging
b. Starring
c. Racking
d. Spoking

14. Control the amplification of echoes received is used to. . . . .

a. Focus
b. Gain
c. Differentiatorn
d. Brilliance

15. The advantages of a GPS satellite system compared to other navigational aids
is ?
a. The GPS system has a build in gorup of six radio beacons called a decca
chain
b. The GPS system gives information about position, speed and time
continously world wide
c. The GPS system gives information about weather and wave conditions in the
area
d. The GPS system is bassed on hyperbola navigation

16. What is the function of a corner reflector. . . . .

a. Detect targets bellow the radar horizon
b. Increase the detectability of small targets
c. Enable the radar to examine shadow areas
d. Increase the radar power output

17. Which affects the strenght rather than the direction of the reflected radar
energy, what the factor is. . . . .
a. Target shape
b. Target surface texture
c. Target aspect
d. Target size

18. What is the requirements for using radar for collision advance are described in.
....
a. International Regulations for Prevention of Collisions at Sea
b. Radar Manual Vol. 2
c. Marine Orders Part 21
d. Admiralty List of Radio Signals
19. Acronym of EBL ?
a. Electric Bearing Line
b. Electronic Bearing Line
c. Electronic Bearing Liner
d. Electric Bearing Liner

20. What would be the most probable cause of the error, when using the echo
sounder in a river the soundings indicated may be incorrect ?
A. The density of the water
B. The strength of the tide and current in the river
C. Shallow water effects
D. There should be no error with a properly working echo sounder

21. Where will you find the number of the chart ?

a. Always outside the right hand margin
b. At the bottom right hand corner and top left hand corner outside the
margin
c. Bellow thye chart title
d. Always outside the left hand margin

22. The critical time while anchoring in a strong current and narrow channel is ?
a. When the ship is “brought up” to the anchor
b. When the ship stops in the water before the anchor is dropped
c. When the speed drops bellow steerage way
d. When the anchor has been dropped

23. The transmitter is have a main component, what is the. . . . .

a. Cathode ray tube
b. Antenna
c. Power supply
d. Magnetron

24. The quantity s, in the equation d = (t x s) r2, is. . . . .

a. The width of the scanner
b. The range scale in use
c. The speed of the radar waves
d. The diameter of the radar screen

25. Uses pulse in radar transmission in order to. . . . .

a. Avoid interference
b. Detect close range targets
c. Conserve energy
d. Counteract bad weather
26. Radar 10 cm also called ?
a. X band
b. S band
c. M band
d. L band

27. The best land target to use for a radar bearing is. . . . .
a. A large headland
b. A coastal indentation
c. A small isolated feature
d. A sloping foreshore

28. If possible, when choosing objects for position fixing by radar ranges you
should, to avoid. . . . .
a. Sloping land features
b. Small isolated features
c. Steep faced features
d. Large prominent features

29. Which of these factors does bearing resolution depend on ?

a. PRF
b. HBW
c. VBW
d. Peak power of the set

30. How can ARPA assist th ship to steer a suitable course to make good the
entrance to a channel . . . . .
a. Select true ground stabilised vectors and make the vectors from both buoys
at the entrance to the channel pass either side of the centre of the screen.
b. Select ground stabilised true motion display and alter course so that own
ships true vector passes through the middle of the entrance to the
channel
c. Select relative motion display and make own ship vector pass through the
middle of the entrance to the channel
d. Acquire the buoy at the entrance to the channel and on relative vector
display alter course to make the vector of the bouy pass directly through
the centre of the screen

31. Target ranges are obtained from. . . . .

a. The pulse repetition frequency
b. Tha range marker
c. The bearing marker
d. The heading marker
32. What is used to warn the observer if any distinguishable target closes to a range
or transits a zone chosen by theobserver ?
a. Guard rings and zones
b. Target lost warning
c. Collision course warning
d. CPA warnings

33. What is the main component in the display unit ?

a. T/R cell
b. Waueguide
c. Scanner
d. Cathode ray unit

34. Where shall the warning signals be placed if a work is performed on the radar
mast ?
a. Warning platest fastened to the mast and each radar
b. Warning notes on all the doors to the
c. Warning notes on all the doors to the bridge
d. Warning plate attached to the mast

35. To warn the observer if any distinguishable target closes to a range or transits
a zone chosen by the observer, it is used ?
a. CPA warnings
b. Target lost warning
c. Collision course warning
d. Guard rings and zone

36. What is the acronym PPI ?

a. Plan Position Indicator
b. Plan Positioning Indicator
c. Plan Positioning Indicating
d. Plan Position Indicating
37. What is the two of most important input information required to operate the
ARPA accurately . . . . .
a. Heading and GMT time
b. Position and GMT time
c. Speed and heading
d. GMT time and speed
38. Where shall the warning signal be placed if a work is performed on the radar
mast ?
a. Warning notes on all the doors to the
b. Warning notes on all the doors to the bridge
c. Warning plates fastened to the mast and each radar
d. Warning plate attached to the mast

39. What is the called of a reference for target bearings is provided by a line on
the radar screen . . . . .
a. Scanner line
b. Heading marker
c. Timebase
d. Centre line

40. How often should anchor bearings be taken, while as vessel is at anchorage ?
a. They are only required if the weather is bad
b. At least every hour
c. At least every four hours
d. In accordance with local port state rules

41. The PPI known as the ability of a radar set to clearly distinguish two target, on
the same range and sightly different bearings, as two separate targets on ?
a. Range descrimination
b. Minimum range
c. Maximum range
d. Bearing discrimination

42. What is the suggested navigational system is a “hyperbolic” navigational system

and has hyperbola as position lines ?
a. GPS
b. All of the suggested systems
c. Radio direction finder
d. Loran C

43. What is the vector mode selected on the arpa when the ship is navigating in
dense fog where the visibility is less than one mile. The arpa radar is set on a
range 12 miles on a course of 314 degrees and own ship has a vector as shown
.....
a. Relative vectors
b. Relative vectors, ground stabilized
c. True vectors
d. Relative vectors, sea stabilized
44. Which of these is a result of true motion display ?
a. All objects move relatively on the PPI
b. CPA and time obtained only by plotting triangle of relative velocities
c. CPA and ime directly obtained
d. Course, speed and aspect of any target obtained only by plotting of
triangle of relative velocities

45. What is the name of rate at which two moving objects approach are separate
from each other called ?
a. Relative distance
b. Relative movement
c. Relative speed
d. Relative bearing