3. Menghitung dan Menggunakan Kesalahan
Kompas.
(Determine
and allow for compass errors )
1. Gyrocompass repeaters
reproduce the indications of the master gyrocompass. They are
B. Accurate electronic
servomechanisms
2. Lines on a chart which connect points of equal magnetic variation are called
D. Isogonic
lines
3. You are proceeding up a channel at night. It is
marked by a range which bears 185°T. You steady up on a compass course of 180°
with the range in line dead ahead This indicates that you(r) .
|
C. |
Compass has some
easterly error |
4. As
a vessel changes
course to starboard,
the compass card
in a magnetic
compass
A.
Remains aligned with compass north
5. You would find the variation
on a polyconic projection chart
A. On
the compass rose
6. What
is an advantage of the magnetic compass aboard vessels? 
C. It is reliable due to it's essential simplicity.
7. 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?
|
A. |
Relative |
8. Magnetic
compass deviation
B. Is the angular difference
between magnetic north and compass north
9. Deviation in a compass is
caused by the
D.
Influence of the magnetic materials of the vessel
10. Magnetic variation changes
with a change in .
D.
The vessel's position
11. What is the basic principle of
the magnetic compass?
A.
Magnetic materials of the same polarity repel each other and those of opposite
polarity attract.
12. Variation is not constant; it
is different with every change in 
.
C.
Geographical location
13. Variation is the angular
measurement between .
C.
Magnetic meridian and the geographic meridian
14. A relative bearing is always
measured from
.
D.
The vessel's head
15.
The
compass rose on a nautical chart indicates both variation and .
B. Annual rate of variation change
16. At the magnetic equator there is no induced
magnetism in the vertical soft iron because
A. The
lines of force cross the equator on
C. There is no vertical component
of the Earth's magnetic field
17. The greatest directive force is exerted on the magnetic compass when the
D. Vessel is near the magnetic equator
18. The
magnetic compass magnets are acted on by the horizontal component of the
Earth's total magnetic force. This magnetic force is GREATEST at the 
D. Magnetic Equator
19. The standard magnetic compass heading differs from the true heading by
A. Compass
error
20. Compass
error is equal to the
C.
Combined variation and deviation
21. When changing from a compass course to a true course you should apply
C. Variation
and deviation
22. Which error is NOT included in the term "current" when used in relation to a fix?
C. Known compass error
23 To center a compass bowl in its binnacle, you
should have the ship on an even keel, heading north or south, and adjust the
screws until 
.
C. No change of heading
by compass is observed if you raise and lower the heeling magnet
24. When crossing the magnetic
equator the
.
B.
Heeling magnet should be inverted
25. The quadrantal spheres are
used to
A.
Remove deviation on the intercardinal headings
26. The purpose of the soft iron
spheres mounted on arms on the binnacle is to compensate for
D.
Induced magnetism in the horizontal soft iron
27. Which
compensates for induced magnetism in the horizontal soft iron of a vessel?
A. Iron spheres mounted on the binnacle
28. Deviation
which is maximum on intercardinal compass headings may be removed by the .
D.
Soft iron spheres on the sides of the compass
29. You are about to go to sea and adjust the magnetic compass. To expedite the adjustment at sea, in what order should the following dockside adjustments be made?
C.
Flinders bar first, then the spheres and heeling magnet
30. When adjusting a magnetic compass using the
fore-and-aft permanent magnets, you should
C.
Use the magnets in pairs, from the bottom up, with the trays at the lowest
point of travel
31. The Flinders bar on a magnetic
compass compensates for the
A.
Induced magnetism in vertical soft iron
32. The
vertical component of the Earth's magnetic field causes induced magnetism in
vertical soft iron. This changes with latitude. What corrects for this
coefficient of the deviation?
33. A
single vertical magnet placed underneath the compass in the binnacle is used to
compensate for 
.
34. What
are the only magnetic compass correctors that correct for both permanent and
induced effects of magnetism?
|
B. |
Heeling magnets |
35. Which
compensates for errors introduced when the vessel heels over?
C. A single vertical magnet
beneath the compass
36. 
Heeling
error is defined as the change of deviation for a heel of .
B. 1°While the vessel is on a compass heading of 000°
37.The total magnetic effects which cause
deviation of a vessel's compass can be broken down into a series of components
which are referred to as .
B. Coefficients
38. When adjusting a magnetic compass for error, a deviation table should be made
C. After adjusting the fore-and-aft and athwartships
permanent magnets
39. The
principal purpose of magnetic compass adjustment is to
B.
Reduce the deviation as much as possible
40. If a
ship is proceeding towards the magnetic equator, the uncorrected deviation due
to permanent magnetism
|
C. |
Decrease |
41. If the compass heading and the magnetic heading are the same then
D. There is no deviation on that heading
42. How is the annual rate of change for magnetic variation shown on a pilot chart?
A. Gray lines on the uppermost inset chart
43. Deviation
is the angle between the
C.
Magnetic meridian and the axis of the compass card
44. Which information does the outer ring of a
compass rose on a nautical chart provide?
B. True directions
45. The horizontal angle between the magnetic
meridian and the north-south line of the magnetic compass is
A.
Deviation
46. On a nautical chart, the inner
ring of a compass rose indicates
D.
Magnetic directions
47. How is variation indicated on
a small-scale nautical chart?
C.
Isogonic lines
48.
Deviation changes with a change in 
B.
Heading
49. On a nautical chart, the inner
ring of a compass rose indicates
D.
Magnetic directions
50. If a
magnetic compass is not affected by any magnetic field other than the Earth's,
which statement is TRUE?
|
A. |
Compass error and
variation are equal. |
51. The
annual change in variation for an area can be found in 
B.
The center of the compass rose on a chart of the area
52. Variation is a compass error
that you
D.
Cannot correct
53. The lubber's line on a
magnetic compass indicates
B.
The direction of the vessel's head
54. The directive force of a
gyrocompass
B. Decreases with latitude, being
maximum at the geographic equator
55. Which statement about the gyrocompass is FALSE?
A. Its accuracy remains the same at all latitudes.
56. The gyrocompass error resulting from your
vessel's movement in OTHER than an east-west direction is called .
D.
Speed error
57. A system of reservoirs and connecting tubes in
a gyro compass is called a
B. Mercury ballistic
58. At the master gyrocompass, the compass card is
attached to the
B. Sensitive element
59. Indications of the master gyrocompass are sent to remote repeaters by the
B. Transmitter
60. If the gyrocompass error is east, what
describes the error and the correction to be made to gyrocompass headings to
obtain true headings?
A.
The readings are too low (small numerically) and the amount of the error must
be added to the compass to obtain true
61. Which statement about
gyrocompass error is TRUE?
A.
The amount of the error and the sign will generally be the same on all headings.
62. The most accurate method of determining gyrocompass error while underway is by
A.
Comparing the gyro azimuth of a celestial body with the computed azimuth of the
body
.
63. To find a magnetic course from a true course you must apply
C. Variation
64. Magnetic
information on a chart may be .
D.
All of the above
65. You are proceeding up a
channel at night. It is marked by a range which bears 185°T. You steady up on a
compass course of 180° with the range in line dead ahea This indicates that
you(r) .
C. Compass has some easterly error
66. Horizon
earth rate causes a free spinning gyro
to appear to an observer on the earth
C, Slow down
67. If your gyro compass reads 20 degrees lower than your magnetic compass
B. The gyro is experiencing a large amount of
deviation
68. Gyroscopic
inertia is that force which causes a gyroscope to
B.
Remain pointing at a fixed point in space
69. Vertical earth rate is 
A.
Maximum at the poles
70. A torque applied carefully to one of the rings housing a gyro will cause the gyro to
A. Swing wildly about
71. The
earth‘s magnetic field is
D. The only force effecting a
magnetic compass
72. While
your vessel is proceeding down a channel you notice a range of ligths in line
with your mast. If your vessel on a course of 001° per gyro compass and the
charted value of the range of lights is 359° T, what is the gyro error ?
A. 2° W
B. 2° E
73. Your vessel is proceeding up a channel, and you see a pair of range lights that are in line ahead The chart indicates that the direction of this pair of lights is 311° T, and the variation is 8° E. If the heading of your vessel at the time of sighting is 305° PSC, what is the correct deviation ?
B. 2° W
74. You are swinging ship to determine the residual
deviation by comparing the magnetic compass against the gyrocompass. The gyro
error is 2° W. The variation is 8° W. After completing the swinging you have
the following readings :HEADING HEADING PSC - PGC PSC – PGC 358.5° - 354°
122.5° -114° 030.5° - 024° 152.0° -144° What is the deviation on a true heading
of 157° ?
D. 0°
HEADING PSC – PGC 239.5° -234° 269.0° -264° 69
75. You are heading 328° PGC to
make good a course of 332° T, correcting for 3° of leeway due to southwesterly
winds and 1° E gyro error. If the variation is 17° E, what should the heading
be to make good 332°T. If you were steering by magnetic compass ? DEVIATION
TABLE
A.
315° MAGNETIC HEADING DEVIATION
76. Your vessel is steering course 216°psc, variation for the area is 9° W, and the deviation is 2° E. The wind is from the east, proceeding a 5° leeway. What true course are you making good ?
C. 343°
77. You are enroute to assist vessel Vessel A is
underway at 4.5 knots on course 233°T, and bears 264°T at 68 miles from you.
What is the course to steer at 13 knots to intercept vessel A?
B.
256°
78. Deviation in a compass is
caused by the
.
D.
Influence of the magnetic materials of the vessel
79. As a vessel changes course to starboard, the compass card in a magnetic compass
C. Remains aligned with compass north
80. Magnetic
variation changes with a change in .
D.
The vessel's position
81. What is the basic principle of
the magnetic compass?
A. Magnetic materials of the same
polarity repel each other and those of opposite polarity
attract.
82. Variation is not constant; it
is different with every change in 
C.
Geographical location
83. Magnetism
which is present only when the material is under the influence of an external
field is called .
|
B. |
Induced
magnetism |
84. Variation
is the angular measurement between .
C.
Magnetic meridian and the geographic meridian
85. A relative bearing is always
measured from
.
D.
The vessel's head
86. The
compass rose on a nautical chart indicates both variation and .
B. Annual rate of variation change
87. At the magnetic equator there is no induced magnetism in the vertical soft iron because .
C. There is no vertical component
of the Earth's magnetic field
88. The greatest directive force is exerted on the
magnetic compass when the D. Vessel is near the magnetic equator
89. The magnetic compass magnets are acted on by
the horizontal component of the Earth's total magnetic force. This magnetic
force is GREATEST at the
D. Magnetic equator
90. The standard magnetic compass
heading differs from the true heading by
A.
Compass error
91. Your
ship is proceeding on course 320°T at a speed of 25 knots. The apparent wind is
from 30° off the starboard bow, speed 32 knots. What is the relative direction,
true direction and speed of the true
wind?
A.
Relative 80°true 040°T, 16.2 knots
92. The compass heading of a
vessel differs from the true heading by
A. Compass error
93. Compass error is equal to the
C.
Combined variation and deviation
94. When
changing from a compass course to a true course you should apply
C. Variation and deviation
95. Which error is NOT included in the term "current" when used in relation to a fix?
C. Known compass error
96. How
many degrees are there on a compass card?
A.
360°
97. To center a compass bowl in
its binnacle, you should have the ship on an even keel,heading north or south,
and adjust the screws until .
C. No change of heading
by compass is observed if you raise and lower the heeling magnet
98. When crossing the magnetic
equator the
B.
Heeling magnet should be inverted
99. The quadrantal spheres are
used to
A.
Remove deviation on the intercardinal headings
100. The purpose of the soft iron
spheres mounted on arms on the binnacle is to compensate for 
.
D. Induced magnetism in
the horizontal soft iron
101. Which compensates for induced
magnetism in the horizontal soft iron of a vessel?
A.
Iron spheres mounted on the binnacle
102. When adjusting a magnetic
compass for error, a deviation table should be made
C.
After adjusting the fore-and-aft and athwartships permanent magnets
103. The total magnetic effects
which cause deviation of a vessel's compass can be broken down into a series of
components which are referred to as
B.
Coefficients