問題一覧
1
There are two guard zones on your ARPA. What is the inner guard zone's purpose?
Warning of small targets that are initially detected closer than the outer guard zone
2
What is the zenith distance of star Dubhe, if the sextant altitude 41° 17.2', index error 1.8' of the arc, dip correction 8.1' and refraction 1.1'?
48° 50.2'
3
What is the estimated distance that you will first sight the light if the visibility is 6 and your eye height is 52ft, given that the light list specifies that a navigational light has a 15-miles nominal range and is 29ft above water?
11.0 miles
4
In heavy weather, what operational control of a RADAR would you choose if you wish to eliminate unwanted echoes?
Sea clutter
5
In a special case in navigation, with bearing relative to the ship's heading, if you employ the method of doubling the angel, how could you find the distance off at the 2nd bearing?
The distance run is multiply by 1.0
6
Base on what you know, which of the four adjustable errors in the sextant causes side error?
Horizon glass not being perpendicular to the frame
7
You are using RADAR in which your own ship is shown at the center of the PPI scope and the heading flash always point to 359°. What seems to be the display setting of your radar?
Relative motion north-up display
8
In the following navigation systems, which positioning is derived from the used of natural land marks?
Terrestrial navigation
9
What would be the theoretical detection range of an object 81 meters High from a ship with an aerial antenna 16 meters above sea level?
About 29 miles
10
How would you distinguish an associated navigation mark in the chart where the color of which are being written in capital letters?
These are conspicuous and larger coastal mark
11
What is the most reliable way to check your plan course to see that you will not encounter iceberg?
Refer to the months pilot charts
12
How would you ensure that the vessel is always in a safe water when travelling through a bouyed channel?
Never rely on a floating aid to maintain vessel's position
13
When using GPS, how many theoretical position lines are required for a three-dimensional fix that takes into account altitude?
4
14
How would you classify the total amount of time which the chronometer has last gained since the date of the given error?
Accumulated rate
15
Which of the following best describe margin of safety?
it is a line parallel to the tract within which the vessel will always be in safe water
16
How would you pass a buoy showing a quick white light and shows six (6) flashes and then one long flashing lights?
I would pass on the South side of the mark
17
How would you classify the line connecting Vernal equinox to autumnal equinox?
It is called the line of equinoxes
18
The altitude at LAN may be observed by starting several minutes in advance and continuing until a maximum altitude is being reached. What condition where in this procedure should not be used?
On a fast vessel with northerly or southerly heading
19
If you set your RADAR on a true motion display, which of the following will appear to move across the PPI scope
Own ship's marker
20
When you are steering your course on a pair of range lights and find the upper light is above the lower light what you should do for safety of navigation?
You should continue on the present course
21
What would be the geographic longitude of a body whose GHA is 215°15'?
144°45'E
22
What is the used of the equation of time taken from the Nautical Almanac for the use in celestial navigation?
It is used to determine time of local apparent noon
23
The height of the observer eye 14.0 meters; Dip 6.6' and refraction 1.7' : The observed sextant altitude of star Dubhe was 29°17.2'. What is the true altitude of star Dubhe if the index error is 1.8' off the arc?
29° 10.7'
24
If you are approaching a light fitted with a RACON, how could you identified the light on the radar?
A coded signal appearing on the same bearing at a greater range than the light
25
What is the estimated distance that you will sight the light if the visibility is 20 miles and your eye height is 20ft, given that the light list specifies that a light as a 20-mile nominal range and 52ft height?
13.5 nm
26
The observed sextant altitude of star Pollux was 31° 17.2', index error 1.8' off the arc, observer height of eye is 15 meters, with the following apparent correction, dip 6.8' and refraction 1.6'. What is the true altitude of star Pollux?
31° 10.6
27
What is the reason why the moon upper limb observation is used more often than those of sun which is observe in the lower limb?
Because of the location of the Moon in sky and its phase
28
When does the ARPA swap targets when automatically tracking two targets?
When the targets pass close together
29
What is the angular difference between the GHA of the body and the longitude of the observer?
Meridian angle
30
An object that is 70ft above water, what estimated geographic visibility for an observer with a 65ft eye height it can be seen?
19.0 nm
31
What is the term when the intercept of an observed star is plotted on a navigational chart?
Line of position
32
Can you identify which of the four adjustable errors in the sextant is the principle cause of index error?
Index mirror and horizon glass not being parallel
33
What appear to be your radar setting if your ship is displayed in the middle of the PPI scope, with the heading flash set 359 degrees?
Relative motion north-up display
34
What is meant when a planetary aberration is due?
It is in part to the body's orbital motion during the time required for it's light to reach earth
35
When position intersect to form a triangle, how would you determine the vessel's position?
The position is in the geometric center of the triangle
36
Your vessel is equipped with both 10cm and a 3cm RADAR. In what function do you think a 3 cm radar is a better provider?
Range discrimination
37
If you are on the Northern Hemisphere, what is the name of the so called pole star
Polaris
38
How many fixed objects are needed to plot a running fix?
One
39
How would you correct your sextant if you have an excessive index error?
Adjust the horizon glass to make it perpendicular to the sextant frame
40
In the Northern Hemisphere in what constellation can you find the star Polaris?
Ursa Minor
41
What is the intersection of a horizontal plane with the celestial sphere if the plane passes through the eyes of the observer?
The intersection is the sensible horizon
42
What do you think is the reason why the upper limb observation of the moon are more used frequently than those of the sun which is the lower limb?
Because of the location of the Moon in sky and its phase
43
What is the diagram where the celestial equator appears as a circle and celestial meridians and hour circles as radial lines?
The time diagram
44
Glancing in the sky at night time how would you classify the constellation Denebola?
It is found in the constellation of Leo
45
When making an ocean passage plan what is the use of gnomonic chart?
To plot the great circle course and waypoint for quick reference
46
What is the error of a sextant that is not adjustable?
Prismatic error
47
When will a radar contact remain stationary on a relative motion display?
On the same course and speed as your vessel
48
What correction you will apply when the index error of the sextant is OFF the arc
Positive correction
49
In taking an amplitude, what will be the location of the observer when the Sun's center should be observed on the visible horizon?
In high Altitude
50
What causes the error of collimation with regards to the four adjustment of a marine sextant?
Telescope not parallel to the frame
51
When a vessel receives a notice to mariners, how long should they be kept before being discarded?
Two years
52
If the observed sextant altitude of star alkaid was 31° 22.2', index error 2?0' off the arc, dip is 3.0' and refraction 1.6', what is the zenith distance of star Alkaid?
58° 40.6'
53
What do you think is the major challenge when the navigator use the moon for celestial sight observation?
The lack of well defined limb at certain position in the sky
54
What should you consider when using a buoy to aid in fixing your ship position?
The buoy may not be in the charted position
55
How would the signal appear on the PPI display of a radar screen, if you are scanning a buoy fitted with a RACON?
Starting with a dash and extending radially outward from the target
56
You are approaching port when the ships agent send you excerpt of a notice to mariners correction as it is concern to your destination. How would you know that correction is already applied in the affected chart?
Check at the left lower corner of the chart if the particular correction is recorded
57
What do you call the bending of light beam as it crosses obliquely from one medium into another of different density?
Refraction
58
What is the part of a sextant that is mounted directly over the pivot of the index arm?
Index mirror
59
If you are in a low latitudes, when will the full Moon rise?
It will always rise at about sunset
60
You depart from latitude 10 degrees north and steams on course 000° T for 1200 nautical miles. What is the new latitude?
Lat 30° 00'N
61
Where does a navigator based his calculation to illustrate the angels involve at meridian transit?
Plane of the observer's meridian
62
When can you say that Superior conjunction occurs?
When the Sun is between the Earth and a planet
63
Which of the following is the condition when the zenith distance of the body is 0 degree?
The body is on the prime vertical
64
In what constellation can you found Fomalhaut?
Pisces
65
Where do you measure the azimuth angle of a sun?
Principal vertical circle
66
In which of the following is the primary caused of marine sextant index error?
the horizon glass not being parallel to the index mirror
67
How would you classify the solving of twilight time as a matter of preparation in star sight may it be evening or morning where the sun is 10 degrees below the horizon?
Observational twilight
68
What correction would you will apply when the index error of the sextant is ON the arc?
Negative correction
69
Can you identify from the following where a time diagram of the celestial sphere is observed?
From above of the south celestial pole
70
What phenomenon is most likely to generate a continuous trace that isn't from the actual ocean bottom when using a depth finder in the open ocean?
It will generate echoes from depth scattering layer
71
The IALA Maritime bouyage system what does a red and white vertically-stripped bouys signifies
Safety water mark
72
What conclusions can you draw in the principle of a sextant when a plane surface reflects a light ray?
The angle of reflection equals the angle of incidence
73
You are running parallel to the coast and take a running fix using bearing of the same object. If you are making less speed than used for the running fix, What will you be in relation to the position indicated by the fix?
Will be closer to the coast
74
How would you determine the actual water depth on the fathometer reading
You should add the draft of the vessel
75
When navigating using GPS, what is an indicator of the geometry of the satellite that your receiver is locked onto?
Horizontal Dilution of Precision
76
How would you correct an index error on a marine sextant?
By adjusting the micrometer drum
77
You are navigating on a course of 343 degrees True. A light buoy bears 8 degrees on the starboard bow at a distance of 12.3 miles. What course would you steer to pass 3 miles abeam of the light buoy leaving it to the starboard?
336 deg. 53 mins 00 secs
78
What is the latitude of a place where the length of the day is 2/5 The length of the night if the Sun's declaration is 20 deg. 20 mins South?
Lat. 39 deg. 49 mins 28 secs N
79
What is a small circle of the celestial sphere parallel to the celestial equator and transcribed by the daily motion of the body?
Parallel of declaration
80
At what distance does the great circle track provide maximum saving?
easterly courses in high latitudes
81
What is a chart position enclosed by a semi-circle?
Dead reckoning position
82
How could you determine a closest point of approach (CPA) of a contact on a relative motion radar?
After the contact has been marked at least twice
83
At the time of meridian passage the navigator observe the sun bearing north. What is the navigator latitude, if the Sun's declaration is 23° N and the observe corrected altitude is 72° 39'?
5° 30.0' N
84
When the moon is at first quarter or third quarter phase, what type of tides will occur?
Neap tide
85
What is the true altitude of star Pollux if the observed sextant altitude was 31° 17.2'; index error is 1.8' off.the arc; height of eye is 15.0 meters with the following apparent correction; dip 6.8' and refraction 1.6'?
31° 10.6'
86
It is a branch of navigation where ships are piloted safely and positions can be fixed by other means especially during heavy weather and visibility is zero?
Electronic navigation
87
In the celestial equator system of coordinates what is equivalent to the co- latitude of the earth system of coordinates?
Polar distance
88
You are navigating at speed of 10 knots. At 1800H you observe a radar contact dead ahead at range of 10 miles then at 1812H the contact is dead ahead at range of 8 miles. What is the estimated speed of the contact?
Dead in the water
89
How would you distinguish a multiple echoes in the radar screen?
This happen and recognizible when a radar beam bounces back and forth between ship and a relatively close in target.
90
At evening twilight, the first star that should be observed are those with an azimuth in what quadrant?
Eastern