第三节 磁罗经与陀螺罗经的使用
运城人事-苑国辉
磁罗经与陀螺罗经的使用
1、
A ship under
construction or major repair will acquire
permanent magnetism due to
______ while
sitting stationary in the earth's magnetic field．
a
A．hammering and jarring
B．vibration and
pounding
C．varying magnetic fields
D．stable or permanent magnetism of the ship
2、
A vessel is heading magnetic east and
its magnetic compass indicates a heading of
086°．Which action should be taken to remove
this error during compass adjustment
________．
a
A．If the blue ends of the magnets are
aft，and the fore-and-aft tray is at the top，you
should add some magnets
B．If the blue ends
of the magnets are aft you should lower the fore-
and-aft tray
C．If the blue ends of the magnets
are aft，and the fore-and-aft tray is at the
top，you
should reverse the magnets
D．If
the blue ends of the magnets are forward，and the
fore-and-aft tray is at the
bottom，you should
add some magnets
3、
A vessel is heading
magnetic northwest and its magnetic compass
indicates a
heading of 312°．What action should
be taken to remove this error during compass
adjustment ________． a
A．If the
quadrantal spheres are all the way out，replace
them with smaller spheres
B．If the quadrantal
spheres are all the way in，replace them with
larger spheres
C．If the quadrantal spheres are
all of the way out，move the spheres in
D．If
the quadrantal spheres are all the way out，replace
them with larger spheres
4、
Any piece of
metal on becoming magnetized will develop regions
of concentrated
magnetism called ______． b
A．flux
B．poles
C．magnets
D．azimuth
5、
By convention，the north seeking ends of
a compass' magnets are colored
______．c
A．Black
B．Blue
C．Red
D．White
6、
If a ship is proceeding towards the
magnetic equator，the uncorrected deviation due
to permanent magnetism ______． c
A．Increases
B．Remains the same
C．Decreases
D．Is unimportant and may be
neglected
7、
In more recent years，______
has been used by civilians in many new ways to
determine positions，such as in automobile and
boat navigation，hiking，emergency
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rescue，and precision agriculture and
mining．a
A．GPS
B．GMDSS
C．AIS
D．Navtex
8、
Indications of the master
gyrocompass are sent to remote repeaters by the
______．b
A．Follow-up system
B．Transmitter
C．Phantom element
D．Azimuth motor
9、
Lines on a chart which connect points of
equal magnetic variation are called
______． d
A．Magnetic latitudes
B．Magnetic
declinations
C．Dip
D．Isogonic lines
10、
Magnetic variation changes with a
change in ______． d
A．the vessel's heading
B．sea conditions
C．seasons
D．the
vessel's position
11、
The agonic line on an
isomagnetic chart indicates the ______． c
A．Magnetic equator
B．Magnetic longitude
reference line
C．Points where there is no
variation
D．Points where there is no annual
change in variation
12、
The angular
difference between the true meridian（great circle
connecting the
geographic poles）and the
magnetic meridian（direction of the lines of
magnetic flux）
is called ______． b
A．deviation
B．variation
C．error
D．difference
13、
The compass error of a
magnetic compass that has no deviation is ______．
b
A．Zero
B．Equal to variation
C．Eliminated by adjusting the compass
D．Constant at any geographical location
14、
The difference between magnetic heading
and compass heading is called
______．b
A．Variation
B．Deviation
C．Compass error
D．Drift
15、
The error in a magnetic compass
caused by the vessel's magnetism is called
______． b
2
A．Variation
B．Deviation
C．Compass error
D．Bearing
error
16、
The Flinders bar and the
quadrantal spheres should be tested for permanent
magnetism at what interval ________． c
A．They are not subject to permanent magnetism;
no check is necessary
B．Semiannually
C．Annually
D．Every five years
17、
The Flinders bar on a magnetic compass
compensates for the ______． a
A．Induced
magnetism in vertical soft iron
B．Induced
magnetism in horizontal soft iron
C．Permanent
magnetism in ship's steel
D．Vessel's
inclination from the vertical
18、
The
gyrocompass error resulting from your vessel's
movement in OTHER than an
east-west direction
is called ______． d
A．Damping error
B．Ballistic deflection
C．Quadrantal error
D．Speed error
19、
The line which
connects the points of zero magnetic dip is
______． b
A．An agonic line
B．The magnetic
equator
C．A magnetic meridian
D．All of the
above
20、
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
A．north
magnetic pole
B．south magnetic pole
C．magnetic prime vertical meridian
D．magnetic equator
21、
The magnetism in
the various structures of a ship changing as a
result of cruising，
vibration，or aging is
termed ______． b
A．permanent magnetism
B．subpermanent magnetism
C．induced
magnetism
D．variable magnetism
22、
The
most accurate method of determining gyrocompass
error while underway is by
______． a
A．Comparing the gyro azimuth of a celestial
body with the computed azimuth of the
body
B．Comparing the gyro heading with the magnetic
compass heading
C．Determining from the chart
the course made good between celestial fixes
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D．It cannot be determined accurately
at sea due to drift of unknown
currents．
23、
The MOST important feature of the
material used for making the binnacle of a
standard magnetic compass is that it is
______． a
A．nonmagnetic
B．weatherproof
C．corrosion resistant
D．capable of being
permanently affixed to the vessel
24、
The
permanent magnetism of a vessel may change in
polarity due to ______． b
A．Being moored for a
long time on one heading
B．Being struck by
lighting
C．Steaming from the north magnetic
hemisphere to the south magnetic hemisphere
D．Loading a homogenous magnetic cargo such as
steel plate，iron bars，etc．
25、
The
principal purpose of adjustment of the magnetic
compass is to eliminate
______ as far as
possible． c
A．Variation
B．Compass error
C．Deviation
D．Earth's magnetic force
26、
The quadrantal spheres are used to
______． a
A．Remove deviation on the
intercardinal headings
B．Remove deviation on
the cardinal compass headings
C．Remove heeling
error
D．Compensate for induced magnetism in
vertical soft iron
27、
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
A．divisional parts
B．coefficients
C．fractional parts
D．equations
28、
The variation for most given areas
undergoes ______ change，the amount of which
is
also noted on charts． a
A．an annual
B．a
constant
C．a variable
D．an unstable
29、
This induced magnetism ______ the
permanent magnetism already present in the
ship． c
A．will add to
B．will
subtract from
C．may add to or subtract from
D．will not change
30、
Variation in a
compass is caused by ______． b
A．Worn gears
in the compass housing
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B．Magnetism from the earth's magnetic
field
C．Magnetism within the vessel
D．Lack
of oil in the compass bearings
31、
What are
the only magnetic compass correctors that correct
for both permanent
and induced effects of
magnetism ________． b
A．Quadrantal spheres
B．Heeling magnets
C．Athwartships magnets
D．Fore-and-aft magnets
32、
What is an
advantage of the magnetic compass aboard vessels
________． c
A．Compass error is negligible at
or near the earth's magnetic poles
B．It does
not have to be checked as often
C．It is
reliable due to it's essential simplicity
D．All points on the compass rose are readily
visible
33、
What is the basic principle of
the magnetic compass ________． a
A．Magnetic
materials of the same polarity repel each other
and those of opposite
polarity attract
B．The Earth's magnetic lines of force are
parallel to the surface of the Earth．
C．Magnetic meridians connect points of equal
magnetic variation
D．The compass
needle（s）will，when properly compensated，lie
parallel to the
isogonic lines of the Earth
34、
What is used to correct for both
induced and permanent magnetism，and
consequently must be readjusted with radical
changes in latitude ________． d
A．Flinders bar
B．Soft iron spheres
C．Fore-and-aft
permanent magnets in their trays
D．Heeling
magnet
35、
When a magnetic compass is not
in use for a prolonged period of time it should
______． a
A．Be shielded from direct
sunlight
B．Be locked into a constant heading
C．Have any air bubbles replaced with nitrogen
D．Have the compensating magnets removed
36、
When a vessel changes course from one
cardinal heading to another cardinal
heading
while adjusting the compass，which action should be
taken ________． b
A．The course change should
be made rapidly to prevent transient induced
magnetism
while passing the intercardinal
headings
B．After the new heading is
reached，the vessel should steam on that course for
at least
two minutes before the adjustment
C．During the course change，you should gently
tap the compass to remove any error
caused by
friction on the pivot bearing
D．After
steadying on the new heading，the compass card
should be slewed by a
magnet and allowed to
oscillate freely to remove any gaussin error
37、
When crossing the magnetic equator the
______． b
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A．Flinders bar
should be inverted
B．Heeling magnet should be
inverted
C．The quadrantal spheres should be
rotated 180°
D．Flinders bar should be moved to
the opposite side of the binnacle
38、
When
relieving the helm，the new helmsman should know
the ______． a
A．Course per magnetic steering
compass
B．Gyro error
C．Variation
D．Maximum rudder angle previously used
39、
Which compensates for errors introduced
when the vessel heels over ________．c
A．The
soft iron spheres on the arms of the binnacle
B．Magnets placed in trays inside the binnacle
C．A single vertical magnet beneath the compass
D．The Flinders bar
40、
Which magnetic
compass corrector（s）can be set while the vessel is
on a heading
of magnetic north or magnetic
south ________． b
A．Quadrantal spheres
B．Heeling magnets
C．Flinders bar
D．Fore-and-aft magnets
41、
Which
magnetic compass corrector（s）CANNOT be set on a
heading of magnetic
east or magnetic west
________． a
A．Heeling magnet
B．Flinders
bar
C．Fore-and-aft magnets
D．All of the
above can be set on magnetic east or magnetic west
headings．
42、
Which statement about the
Flinders bar of the magnetic compass is CORRECT
________． a
A．It compensates for the
error caused by the vertical component of the
Earth's
magnetic field
B．It compensates
for error caused by the heeling of a vessel
C．It compensates for quadrantal deviation
D．It is only needed in equatorial waters
43、
Which statement about the gyrocompass
is FALSE ________． a
A．Its accuracy remains
the same at all latitudes
B．It seeks the true
meridian
C．It can be used near the Earth's
magnetic poles
D．If an error exists，it is the
same on all headings
44、
While in drydock
your vessel will be belt-gauged．This process
involves ______．d
A．measuring the thickness of
the tail shaft liner
B．taking the vessel's
offsets to check for hull deformation
C．testing and examining the anchor cables for
defective links
D．drilling or sonic-testing
the hull to determine the plate thickness
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