What will cause the ARPA to emit a visual alarm, audible alarm, or both?
|
An
acquired target entering into a guard zone
|
A
tracked target lost for one radar scan
|
A
target being initially detected within a guard zone
|
A
tracked target entering your preset CPA-TCPA limits |
Your ARPA has been tracking a target and has generated the targets course
and speed. The radar did not receive a target echo on its last two scans
due to the weather. What should you expect under these circumstances?
|
The
ARPA will generate data based on sea return echoes from the vicinity where
the target was lost.
|
The
ARPA will give an audible and/or visual lost target alarm.
|
The
ARPA has lost all "memory" of the target and must recompute the
target data.
|
The
ARPA will generate data as if the target was still being tracked by radar. |
|
Vessels required to have an Automatic Radar Plotting Aid must have a device
to indicate the __________. |
ECDIS
generated trackline |
vessel's
position |
AIS
information of vessels in the vicinity |
speed
of the vessel over the ground or through the water |
|
Vessels required to have an Automatic Radar Plotting Aid must have a device
to indicate the __________. |
speed
of the vessel over the ground or through the water |
distance
to the next port |
time
of the next navigational satellite pass |
None
of the above |
|
Your ARPA has automatic speed inputs from the log. Due to currents, the
log is indicating a faster speed than the speed over the ground. What should
you expect under these circumstances? |
The
range of initial target acquisition will be less than normal. |
The
generated CPA will be less than the actual CPA. |
The
generated TCPA will be later than the actual TCPA. |
The
targets true course vector will be in error. |
|
Which ARPA data should you use in order to determine if a close quarters
situation will develop with a target vessel? |
Set
and drift of the current |
Initial
range of acquisition |
Predicted
time of CPA |
Relative
track information |
|
When using an ARPA, what should you consider in order to evaluate the information
displayed? |
Navigational
constraints may require a target vessel to change course. |
You
cannot determine if a small target has been lost due to sea return. |
The
trial maneuver feature will automatically determine a course that will clear
all targets. |
The
target vessel's generated course and speed are based solely on radar inputs. |
|
The ARPA may swap targets when automatically tracking if two targets __________. |
are
tracked on the same bearing |
pass
close together |
are
tracked on reciprocal bearings |
are
tracked at the same range |
|
Your ARPA has two guard zones. What is the purpose of the inner guard zone? |
Sound
an alarm for targets first detected within the zone |
Alert
the watch officer that a vessel is approaching the preset CPA limit |
Guard
against target loss during critical maneuvering situations |
Warn
of small targets that are initially detected closer than the outer guard
zone |
|
What is TRUE of the history display of a target's past positions on an ARPA? |
It
provides a graphic display to emphasize which vessel is on a collision course.
|
In
the true presentation, it provides a quick visual check to determine if
a vessel has changed course.
o |
It
provides a graphic display of a target vessel's relative course, speed,
and CPA.
|
The
display is one of the primary inputs and must be in use when using the trial
maneuver capability. |
|
When using the ARPA in heavy rain, which action should you take? |
Increase
the STC setting to reduce close-in spurious signals. |
Increase
the range of the inner and outer guard rings. |
Navigate
as though the effective range of the radar has been reduced. |
Increase
the radar gain to pick up weak echoes through the rain. |
|
The typical operating range of automatic identification systems (AIS) at
sea is nominally __________. |
6-8
nm |
50-75
nm |
20-25
nm |
3-4
nm |
|
In general, on how many radio channels will an automatic identification
system (AIS) operate? |
2 |
4 |
6 |
8 |
|
An automatic identification system (AIS) transponder transmits and receives
information broadcasts on __________? |
VHF
maritime band |
10
cm, S-band radar |
3
cm, X-band radar |
UHF
L-band |
|
What does an automatic identification system (AIS) transponder use to transmit
and receive information broadcasts? |
161.975
Mhz and 162.025 Mhz |
1575.42
Mhz and 1227.6 Mhz |
2182
Khz and 2187.5 Khz |
3000
Mhz and 9200 Mhz |
|
With respect to automatic identification systems (AIS), which information
is expected to be broadcast every 1 to 10 seconds? |
IMO
number |
Vessel's
draft |
Name
of ship |
Ship's
heading |
|
With respect to automatic identification systems (AIS), which information
is required to be broadcast every 1 to 10 seconds? |
Call
sign and IMO number |
MMSI
number and call sign |
Route
Plan and navigational status |
Course
over ground and MMSI |
|
Automatic identification systems (AIS) are expected to broadcast all of
the following information EXCEPT __________. |
ship's
heading |
time
stamp |
navigation
status |
port
of origin |
|
While underway, a vessel over 100,000 gross tons with an automatic identification
systems (AIS) is expected to broadcast all of the following information
every 1 to 10 seconds EXCEPT __________. |
ship's
heading |
navigational
status |
rate
of turn |
name
of vessel |
|
While underway, automatic identification systems (AIS) broadcast all of
the following information every 1 to 10 seconds EXCEPT the __________. |
latitude
and longitude |
ship's
scantlings |
speed
over ground |
course
over ground |
|
Which information must automatic identification systems (AIS) automatically
provide to appropriately equipped shore stations, vessels and aircraft? |
Vessel's
type |
Vessel's
course |
Navigational
status |
All
of the above. |
|
With respect to automatic identification systems (AIS) which of the following
information is broadcast every one to ten seconds? |
Vessel's
draft |
Dimensions
of vessel |
Air
Draft |
Navigational
status |
|
With respect to automatic identification systems (AIS), which information
is required to be broadcast every 1 to 10 seconds? |
Vessel's
draft |
Call
sign |
Route
plan |
None
of the above |
|
With respect to automatic identification systems (AIS), which information
is expected to be broadcast every 1 to 10 seconds? |
Latitude
and longitude |
Navigational
status |
Rate
of turn |
All
of the above. |
|
With respect to automatic identification systems (AIS), which information
is required to be broadcast every 1 to 10 seconds? |
Destination |
Location
of antenna |
Time
stamp |
None
of the above |
|
Automatic identification systems (AIS) are required to __________. |
receive
safety-related information automatically from similarly equipped vessels |
exchange
safety-related information with shore-based facilities |
provide
safety-related information automatically to shore stations, other vessels
and aircraft |
All
of the above. |
The short text messaging feature of the automatic identification system
(AIS) allows for messages of up to __________.
|
56
characters
|
64
characters
|
128
characters
|
158
characters |
Which of the following statements is TRUE regarding automatic identification
systems (AIS)?
|
AIS
is a short-range 3 cm X-band radar system that automatically sends a vessel's
position, course, speed and other safety related information to all those
with similar equipment within the area.
|
AIS
is a global tracking system that relies upon INMARSAT C service to communicate
vessel position, course, speed and other safety related information to all
those with similar equipment in the area.
|
AIS
is a one-way centrally managed system that requires the local VTS to send
commands to instruct each vessel to broadcast position, course, speed and
other safety related information to all those with similar equipment in
the area.
|
AIS
is a short-range VHF-FM system that automatically broadcasts a vessel's
position, course, speed and other safety related information to all those
with similar equipment in the area. |
Which of the following statements is TRUE regarding automatic identification
systems (AIS)?
|
AIS
is designed to replace ARPA, maneuvering boards, and visual bearings as
a means to ascertain the risk of collision.
|
AIS
will not provide information on another vessel if that vessel is indistinguishable
in radar sea clutter.
|
AIS
provides near real-time information regarding another vessel's speed over
ground and heading regardless of visibility. |
AIS
can be relied upon as the sole means to determine course changes due to
other AIS equipped traffic. |
Which of the following statements is TRUE regarding automatic identification
systems (AIS)?
|
AIS
provides the other vessel's identity, dimensions and navigational status
regardless of visibility.
|
AIS
will not provide information on another vessel if that vessel is indistinguishable
in radar sea clutter.
|
AIS
can be relied upon as the sole means to determine risk of collision and
safe speed.
|
AIS
is designed to replace ARPA, maneuvering boards, and visual bearings as
a means to ascertain the risk of collision. |
Which of the following statements is TRUE regarding automatic identification
systems (AIS)?
|
AIS
cannot be used to make passing arrangements because the system is not capable
of this type of ship-to-ship communications.
|
AIS
can be used to make passing arrangements via ship-to-ship text massaging
thus relieving a vessel operator from making such arrangements via bridge-to-bridge
radiotelephone or signaling intent to pass via whistle signals.
|
AIS
cannot be used to make passing arrangements because the ship-to-ship text
messaging feature is for emergency use only.
|
AIS
can be used to make passing arrangements via ship-to-ship text messaging
but a vessel operator is not relieved from the requirement to sound whistle
signals or make arrangements via bridge-to-bridge radiotelephone. |
|
Which of the following statements is TRUE regarding automatic identification
systems (AIS)? |
Under
no circumstances shall AIS be turned off while underway as this could endanger
the vessel and those around her.
|
The
master may, at his/her discretion, turn off the AIS if he/she believes that
it may compromise the safety or security of the vessel.
|
AIS
is always required to be operating if the vessel is within 100 nautical
miles of the coastline.
|
AIS
is always required to be operating if the vessel is in or in the vicinity
of a VTS area. |
|
Time signals broadcast by WWV and WWVH are transmitted __________. |
every
15 minutes |
every
30 minutes |
continuously
throughout day |
every
hour |
|
Yesterday you took a time tick using the 1200 GMT broadcast, and the chronometer
read 11h 59m 59s. Today at the 1200 GMT time tick the chronometer read 00h
00m 01s. What is the chronometer error? |
Losing
2 seconds |
Gaining
2 seconds |
Fast
1 second |
Fast
2 seconds |
|
Yesterday your chronometer read 03h 01m 56s at the 1500 GMT time tick. Today
your chronometer read 03h 01m 54s at the 1500 GMT time tick. What is the
chronometer rate? |
+2s |
2s
fast |
-2s |
1m
54s fast |
|
Yesterday your chronometer read 11h 59m 59s at the 1200 GMT time tick. Today
the chronometer reads 11h 59m 57s at the 1200 time tick. What is the chronometer
rate? |
-3s |
+2s |
-2s |
+3s |
Yesterday your chronometer read 11h 59m 58s at the 1200 GMT time tick. Today
your chronometer reads 12h 00m 00s at the 1200 time tick. What is the chronometer
rate?
|
Nil
|
12h
|
-2s
|
+2s |
|
Yesterday your chronometer read 03h 01m 56s at the 1500 GMT time tick. Today
your chronometer read 03h 01m 58s at the 1500 GMT time tick. What is the
chronometer error? |
01m
58s fast |
03h
01m 58s fast |
+2s |
-2s |
|
Yesterday your chronometer read 02h 59m 58s at the 1500 GMT time tick. Today
the chronometer reads 03h 00m 02s at the 1500 GMT time tick. What is the
chronometer error? |
03h
00m 02s fast |
+3s |
-3s |
02s
fast |
Chronometer error may be found by __________.
|
radio
time signal
|
applying
the prevailing chronometer rate to previous readings
|
comparison
with a timepiece of known error
|
All
of the above. |
|
A marine chronometer should be rewound once every __________. |
12
hours |
day |
3
days |
week |
|
When using a mechanical (windup type) marine chronometer, how often should
it be reset? |
Whenever
the chronometer error exceeds approximately four minutes |
At
the start of each voyage |
If
the chronometer rate changes from gaining to losing or vice versa |
Only
when it is overhauled |
Yesterday your chronometer read 11h 59m 59s at 1200 GMT time tick. Today
the chronometer reads 12h 00m 01s at the 1200 GMT tick. What is the chronometer
rate?
|
-1s
|
+1s
|
-2s
|
+2s |
|
Quadrantal error in a gyrocompass has its GREATEST effect on which of the
following |
in
high latitudes
|
on
intercardinal headings |
near
the equator |
on
north or south headings |
|
What is the gyrocompass error resulting from your vessel's movement in OTHER
than an east-west direction? |
damping
error |
ballistic
deflection
|
speed
erro |
quadrantal
error |
|
If the gyrocompass error is east, what describes the error and the correction
to be made to gyrocompass headings to obtain true headings? |
The
readings are too high (large numerically) and the amount of the error must
be added to the compass to obtain true
|
The
readings are too low (small numerically) and the amount of the error must
be added to the compass to obtain true |
The
readings are too high and the amount of the error must be subtracted from
the compass to obtain true |
The
readings are too low and the amount of the error must be subtracted from
the compass to obtain true |
Which statement about gyrocompass error is TRUE?
|
The
amount of the error and the sign will generally be the same on all headings. |
The
sign (E or W) of the error will change with different headings of the ship. |
Any
error shown by a gyro repeater will be the same as the error of the master
compass. |
Any
error will remain constant unless the compass is stopped and restarted. |
|
Which of the following is the most accurate method of determining gyrocompass
error while underway |
determining
from the chart the course made good between celestial fixes
|
comparing
the gyro azimuth of a celestial body with the computed azimuth of the body |
comparing
the gyro heading with the magnetic compass heading |
It
cannot be determined accurately at sea due to drift of unknown currents. |
|
How can the accuracy of an azimuth circle be checked? |
sighting
a terrestrial range in line and comparing the observed bearing against the
charted bearing
|
comparing
observed azimuths at different altitudes with computed values at the times
of observation to see if the difference is constant
|
aligning
the relative bearing markings so that 000° is on the lubber's line and the
line of sight passes over the center of the compass
|
ensuring
that the alignment marks on the inner face of the circle are in line with
those on the repeater on relative bearings of 000° and 090° |
|
The reaction of a gyrocompass to an applied force is known as __________. |
gravity
effect |
gyroscopic
inertia |
earth
rate
|
precession |
The spin axis of a gyroscope tends to remain fixed in space in the direction
in which it is started. How does this gyroscope become north seeking so
that it can be used as a compass?
|
By
mechanically or electrically applying forces to precess the gyroscope |
By
taking advantage of the property of gyroscopic inertia |
By
starting the compass with the spin axis in a north/south position |
The
rotation of the Earth (Earth rate) automatically aligns the gyroscope with
north, except for speed errors |
|
The directive force of a gyrocompass __________. |
increases
with latitude, being maximum at the geographic poles |
remains
the same at all latitudes
|
decreases
with latitude, being maximum at the geographic equator |
is
greatest when a vessel is near the Earth's magnetic equator |
|
Which statement about the gyrocompass is FALSE? |
It
can be used near the Earth's magnetic poles. |
It
seeks the true meridian.
|
Its
accuracy remains the same at all latitudes |
If
an error exists, it is the same on all headings. |
|
A system of reservoirs and connecting tubes in a gyro compass is called
a __________. |
spider
element |
mercury
ballistic |
gyrotron |
rotor |
|
At the master gyrocompass, the compass card is attached to the __________. |
pickup
transformer |
sensitive
element |
link
arm |
spider
element |
|
Indications of the master gyrocompass are sent to remote repeaters by the
__________. |
follow-up
system |
transmitter |
phantom
element |
azimuth
motor |
|
Gyrocompass repeaters reproduce the indications of the master gyrocompass.
They are __________. |
hand
operated |
accurate
electronic servomechanisms |
accurate
only in the Polar regions |
accurate
only if the vessel is underway |
|
Compass deviation is caused by __________. |
a
dirty compass housing |
misalignment
of the compass |
magnetism
within the vessel |
magnetism
from the earth's magnetic field |
|
Compass error is equal to the __________. |
difference
between true and magnetic heading |
combined
variation and deviation |
deviation
minus variation |
variation
plus compass course |
|
Error may be introduced into a magnetic compass by __________. |
belt
buckles |
making
a structural change to the vessel |
a
short circuit near the compass |
All
of the above. |
|
The quadrantal spheres are used to __________. |
remove
deviation on the intercardinal headings |
remove
heeling error |
compensate
for induced magnetism in vertical soft iron |
remove
deviation on the cardinal compass headings |
|
The purpose of the soft iron spheres mounted on arms on the binnacle is
to compensate for __________. |
the
residual deviation |
the
vertical component of the permanent magnetism of the vessel |
magnetic
fields caused by electrical currents in the vicinity |
induced
magnetism in the horizontal soft iron |
|
Variation is the angular measurement between __________. |
your
vessel's heading and the magnetic meridian |
compass
north and true north |
magnetic
meridian and the geographic meridian |
compass
north and magnetic north |
|
Which compensates for induced magnetism in the horizontal soft iron of a
vessel? |
Magnets
in trays inside the binnacle |
A
single vertical magnet under the compass |
The
Flinders bar |
Iron
spheres mounted on the binnacle |
|
True heading differs from magnetic heading by __________. |
deviation |
compass
error |
variation |
northerly
error |
|
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? |
The
Flinders bar |
Bar
magnets in the binnacle |
Quadrantal
soft iron spheres |
The
heeling magnet |
|
The difference in degrees between true north and magnetic north is called
__________. |
drift |
compass
error |
variation |
deviation |
|
To find a magnetic compass course from a true course you must apply __________. |
deviation
and variation |
variation |
magnetic
anomalies (local disturbances) |
deviation |
|
The Flinders bar on a magnetic compass compensates for the __________. |
induced
magnetism in horizontal soft iron |
vessel's
inclination from the vertical |
permanent
magnetism in ship's steel |
induced
magnetism in vertical soft iron |
|
Which statement about the Flinders bar of the magnetic compass is CORRECT? |
It
compensates for quadrantal deviation. |
It
is only needed in equatorial waters. |
It
compensates for error caused by the heeling of a vessel. |
It
compensates for the error caused by the vertical component of the Earth's
magnetic field. |
|
A single vertical magnet placed underneath the compass in the binnacle is
used to compensate for __________. |
induced
magnetism in the vertical soft iron |
deviation
caused by the vessel's inclination from the vertical |
induced
magnetism in the horizontal soft iron |
the
horizontal component of the permanent magnetism |
The principal purpose of magnetic compass adjustment is to __________.
|
reduce
the variation as much as possible
|
allow
the compass bowl to swing freely on its gimbals
|
reduce
the magnetic dip as much as possible
|
reduce
the deviation as much as possible |
|
When adjusting a magnetic compass for error, a deviation table should be
made __________. |
after
adjusting the fore-and-aft and athwartships permanent magnets |
before
the quadrantal correctors are placed on the compass |
before
correcting for any deviation |
after
correcting for variation |
|
Deviation which is maximum on intercardinal compass headings may be removed
by the __________. |
soft
iron spheres on the sides of the compass |
fore-and-aft
magnets |
transverse
magnets |
Flinders
bar |
|
Before a magnetic compass is adjusted certain correctors must be checked
to ensure that they are free of permanent magnetism. These correctors are
the __________. |
fore-and-aft
and athwartships magnets |
Flinders
bar and quadrantal spheres |
dip
needle and heeling magnet |
heeling
magnet and Flinders bar |
|
The Flinders bar and the quadrantal spheres should be tested for permanent
magnetism at what interval? |
Semiannually |
They
are not subject to permanent magnetism; no check is necessary. |
Every
five years |
Annually |
|
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 __________. |
equations |
fractional
parts |
coefficients |
divisional
parts |
|
Magnetic compass deviation __________. |
is
the angular difference between magnetic north and compass north |
is
the angular difference between geographic and magnetic meridians |
is
published on the compass rose on most nautical charts |
varies
depending upon the bearing used |
|
If a ship is proceeding towards the magnetic equator, the uncorrected deviation
due to permanent magnetism __________. |
remains
the same
|
is
unimportant and may be neglected
|
decreases |
increases |
If a ship is proceeding towards the magnetic equator, which is TRUE concerning
the uncorrected deviation due to permanent magnetism?
|
The
deviation will increase |
It
is unimportant and may be neglected |
The
deviation will decrease |
It
remains the same |
|
If the compass heading and the magnetic heading are the same then __________. |
there
is something wrong with the compass |
the
deviation has been offset by the variation |
there
is no deviation on that heading |
the
compass is being influenced by nearby metals |
|
If the magnetic heading is greater than the compass heading, the deviation
is __________. |
north |
west |
south |
east |
|
The difference between magnetic heading and compass heading is called __________. |
compass
error |
drift |
variation |
deviation |
|
Deviation is the angle between the __________. |
axis
of the compass card and the degaussing meridian |
true
meridian and the axis of the compass card |
true
meridian and the magnetic meridian |
magnetic
meridian and the axis of the compass card |
|
The horizontal angle between the magnetic meridian and the north-south line
of the magnetic compass is __________. |
deviation |
compass
error |
dip |
variation |
|
The compass deviation changes as the vessel changes __________. |
speed |
longitude |
heading |
geographical
position |
|
Deviation is caused by __________. |
magnetic
influence inherent to that particular vessel |
changes
in the earth's magnetic field |
nearby
magnetic land masses or mineral deposits |
the
magnetic lines of force not coinciding with the lines of longitude |
|
Deviation in a compass is caused by the __________. |
influence
of the magnetic materials of the vessel |
vessel's
geographic position |
vessel's
heading |
earth's
magnetic field |
|
Variation in a compass is caused by __________. |
lack
of oil in the compass bearings |
magnetism
within the vessel |
magnetism
from the earth's magnetic field |
worn
gears in the compass housing |
|
Magnetic variation changes with a change in __________. |
seasons |
sea
conditions |
the
vessel's position |
the
vessel's heading |
|
Variation is not constant; it is different with every change in __________. |
cargo |
speed |
vessel
heading |
geographical
location |
|
If a magnetic compass is not affected by any magnetic field other than the
Earth's, which statement is TRUE? |
There
will be no compass error. |
Compass
error and variation are equal. |
Compass
north will be true north. |
Variation
will equal deviation. |
|
The compass error of a magnetic compass that has no deviation is __________. |
equal
to variation |
zero |
eliminated
by adjusting the compass |
constant
at any geographical location |
|
When crossing the magnetic equator the __________. |
Flinders
bar should be inverted |
Flinders
bar should be moved to the opposite side of the binnacle |
the
quadrantal spheres should be rotated 180° |
heeling
magnet should be inverted |
|
What are the only magnetic compass correctors that correct for both permanent
and induced effects of magnetism? |
Quadrantal
spheres |
Athwartships
magnets |
Fore-and-aft
magnets |
Heeling
magnets |
|
Which compensates for errors introduced when the vessel heels over? |
A
single vertical magnet beneath the compass |
The
soft iron spheres on the arms of the binnacle |
Magnets
placed in trays inside the binnacle |
The
Flinders bar |
|
Heeling error is defined as the change of deviation for a heel of __________. |
1°While
the vessel is on a compass heading of 000° |
2°
and is constant on all headings |
1°
while the vessel is on a compass heading of 180° |
2°While
the vessel is on an intercardinal heading |
|
The standard magnetic compass heading differs from the true heading by __________. |
variation |
latitude |
deviation |
compass
error |
|
When changing from a compass course to a true course you should apply __________. |
deviation |
variation
and deviation |
variation |
a
correction for the direction of current set |
|
The chart indicates the variation was 3°45'W in 1988, and the annual change
is decreasing 6'. If you use the chart in 1991 how much variation should
you apply? |
3°27'W |
3°27'E |
4°03'W |
4°03'E |
|
The chart indicates the variation was 3°45'W in 1988, and the annual change
is increasing 6'. If you use the chart in 1991 how much variation should
you apply? |
3°27'W |
3°27'E |
4°03'W |
4°03'E |
|
The chart indicates the variation was 3°45'E in 1988, and the annual change
is increasing 6'. If you use the chart in 1991 how much variation should
you apply? |
3°27'E |
3°27'W |
3°45'E |
4°03'E |
|
Variation is a compass error that you __________. |
can
correct by adjusting the compass card |
cannot
correct |
can
correct by adjusting the compensating magnets |
can
correct by changing the vessel's heading |
|
Error may be introduced into a magnetic compass by __________. |
making
a structural change to the vessel |
a
short circuit near the compass |
belt
buckles |
All
of the above. |
|
The lubber's line on a magnetic compass indicates __________. |
the
direction of the vessel's head |
magnetic
north |
a
relative bearing taken with an azimuth circle |
compass
north |
|
The MOST important feature of the material used for making the binnacle
of a standard magnetic compass is that it is __________. |
corrosion
resistant |
weatherproof |
capable
of being permanently affixed to the vessel |
nonmagnetic |
|
Which would influence a magnetic compass? |
Electrical
wiring |
Iron
pipe |
Radio |
All
of the above. |
|
As a vessel changes course to starboard, the compass card in a magnetic
compass __________. |
also
turns to starboard |
remains
aligned with compass north |
turns
counterclockwise to port |
first
turns to starboard then counterclockwise to port |
|
The permanent magnetism of a vessel may change in polarity due to __________. |
being
moored on a constant heading for a long period of time |
a
collision with another vessel |
being
struck by lightning |
All
of the above. |
|
Which would influence a magnetic compass? |
Radio |
Iron
pipe |
Electrical
wiring |
All
of the above. |
How can the permanent magnetism of a vessel change in strength?
|
Welding
and major structural repair |
The
nature of the cargo being carried |
Changes
in the vessel's heading |
Geographical
location of vessel |
|
The lubber's line on a magnetic compass indicates __________. |
compass
north |
the
direction of the vessel's head |
magnetic
north |
a
relative bearing taken with azimuth circle |
|
The permanent magnetism of a vessel may change in polarity due to __________. |
the
nature of the cargo being carried |
changes
in heading |
major
structural repair |
All
of the above. |
|
The permanent magnetism of a vessel may change in polarity due to __________. |
being
struck by lighting |
steaming
from the north magnetic hemisphere to the south magnetic hemisphere |
being
moored for a long time on one heading |
loading
a homogenous magnetic cargo such as steel plate, iron bars, etc. |
|
Magnets are placed in horizontal trays in the compass binnacle to compensate
for the __________. |
magnetic
fields caused by electrical currents in the vicinity |
induced
magnetism in the vessel's horizontal soft iron |
change
in the magnetic field when the vessel inclines from vertical |
permanent
magnetism of the vessel |
|
Magnets in the binnacles of magnetic compasses are used to reduce the effect
of __________. |
variation |
deviation |
local
attraction |
All
of the above. |
|
Permanent magnetism is caused by __________. |
the
horizontal component of the earth's magnetic field acting on the horizontal
soft iron |
the
vertical component of the earth's magnetic field acting on the vertical
soft iron |
the
earth's magnetic field affecting the ship's hard iron during construction |
operation
of electrical equipment and generators on board ship |
|
At the magnetic equator there is no induced magnetism in the vertical soft
iron because __________. |
the
lines of force cross the equator on a 0°-180° alignment |
the
quadrantal error is 0° |
there
is no vertical component of the Earth's magnetic field |
the
intercardinal headings have less than 1° error |
|
The greatest directive force is exerted on the magnetic compass when the
__________. |
needles
are nearly in line with the meridian |
vessel
is near the magnetic poles |
vessel
is near the magnetic equator |
variation
is near zero |
|
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
__________. |
south
magnetic pole |
north
magnetic pole |
magnetic
prime vertical meridian |
magnetic
equator |
|
Magnetism which is present only when the material is under the influence
of an external field is called __________. |
residual
magnetism |
permanent
magnetism |
induced
magnetism |
terrestrial
magnetism |
|
Induced magnetism is found in __________. |
hard
iron |
horizontal
iron only |
vertical
iron only |
soft
iron |
|
The line which connects the points of zero magnetic dip is __________. |
an
agonic line |
the
magnetic equator |
a
magnetic meridian |
All
of the above. |
|
The line connecting the points of the earth's surface where there is no
dip is the __________. |
isopor |
agonic
line |
isodynamic |
magnetic
equator |
|
The points on the earth's surface where the magnetic dip is 90° are __________ |
along
the magnetic equator
|
the
magnetic poles |
the
isopors |
connected
by the isoclinal line |
The vertical angle between the horizontal and the magnetic line of force
is the __________.
|
dip |
magnetic
angle |
vertical
angle |
elevation |
|
Magnetic dip is a measurement of the angle between the __________ |
geographic
pole and the magnetic pole
|
horizontal
and the magnetic line of force |
lubber's
line and true north |
compass
heading and the magnetic heading |
|
What is the basic principle of the magnetic compass? |
The
Earth's magnetic lines of force are parallel to the surface of the Earth. |
The
compass needle(s) will, when properly compensated, lie parallel to the isogonic
lines of the Earth.
|
Magnetic
materials of the same polarity repel each other and those of opposite polarity
attract |
Magnetic
meridians connect points of equal magnetic variation. |
|
By convention, the Earth's north magnetic pole is colored __________. |
black |
red
|
blue |
white |
|
By convention, the south pole of a magnet is painted __________. |
red |
black |
white |
blue |
|
By convention, the north pole of a magnet is painted __________. |
red |
blue |
white |
black |
|
By convention, the Earth's north magnetic pole is colored __________. |
black |
red |
blue |
white |
|
By convention, the south seeking ends of a compass' magnets are colored
__________. |
white |
black |
blue |
red |
|
By convention, the north seeking ends of a compass' magnets are colored
__________. |
black |
red |
blue |
white |
|
What is an advantage of the magnetic compass aboard vessels? |
It
does not have to be checked as often. |
Compass
error is negligible at or near the earth's magnetic poles. |
All
points on the compass rose are readily visible. |
It
is reliable due to it's essential simplicity. |
|
When a magnetic compass is not in use for a prolonged period of time it
should __________. |
be
locked into a constant heading |
have
any air bubbles replaced with nitrogen |
be
shielded from direct sunlight |
have
the compensating magnets removed |
|
A magnetic compass card is marked in how many degrees? |
90 |
180 |
360 |
400 |
|
When a magnetic compass is not in use for a prolonged period of time it
should __________. |
have
the compensating magnets removed |
be
shielded from direct sunlight |
have
any air bubbles replaced with nitrogen |
be
locked into a constant heading |
|
A magnetic compass card is marked in how many degrees? |
90 |
180 |
360 |
400 |
|
The heading of a vessel is indicated by what part of the compass? |
Gimbals |
Card |
Lubber's
line |
Needle |
|
How many degrees are there on a compass card? |
360° |
380° |
390° |
420° |
|
What is the compass course of a vessel heading NNW? |
274.5° |
292.0° |
315.5° |
337.5° |
|
What is the compass course of a vessel heading NW? |
274.5° |
292.5° |
315.0° |
337.5° |
|
What is the compass course of a vessel heading SSW? |
202.5° |
225.0° |
247.5° |
270.0° |
|
What is the compass course of a vessel heading SW? |
202.5° |
225.0° |
247.5° |
270.0° |
|
What is the compass course of a vessel heading WSW? |
202.5° |
225.0° |
247.5° |
271.0° |
|
What is the compass course of a vessel heading WNW? |
270.0° |
292.5° |
315.0° |
337.5° |
|
What is the compass course of a vessel heading SSE? |
112.5° |
135.0° |
157.5° |
180.0° |
|
What is the compass course of a vessel heading SE? |
112.5° |
135.0° |
157.5° |
180.0° |
|
What is the compass course of a vessel heading ESE? |
112.5° |
135.0° |
157.5° |
180.0° |
|
What is the compass course of a vessel heading ENE? |
022.5° |
045.0° |
067.5° |
090.0° |
|
What is the compass course of a vessel heading NE? |
022.5° |
045.0° |
067.5° |
090.0° |
What is the compass course of a vessel heading NNE?
|
022.5°
|
045.0°
|
067.5°
|
090.0° |
|
Which of the following is a compass card without north-seeking capability
that is used for relative bearings? |
alidade |
bearing
bar |
bearing
circle |
pelorus |
|
Eight points of a compass are equal to how many degrees? |
45 |
90 |
180 |
360 |
|
One point of a compass is equal to how many degrees? |
7.5 |
11.25 |
17.5 |
22.5 |
|
How many points are there in a compass card? |
4 |
8 |
24 |
32 |
|
The heading of a vessel is indicated by what part of the compass? |
Lubber's
line |
Card |
Needle |
Gimbals |
|
A vessel heading NNW is on a course of __________. |
274.5° |
292.0° |
315.5° |
337.5° |
|
A vessel heading NW is on a course of __________. |
274.5° |
315.0° |
337.5° |
292.5° |
|
A vessel heading NE is on a course of __________. |
022.5° |
045.0° |
067.5° |
090.0° |
|
A vessel heading SSW is on a course of __________. |
202.5° |
225.0° |
247.5° |
270.0° |
|
A vessel heading WSW is on a course of __________. |
202.5° |
225.0° |
247.5° |
271.0° |
|
A vessel heading SSE is on a course of __________. |
112.5° |
135.0° |
157.5° |
180.0° |
|
A vessel heading ESE is on a course of __________. |
112.5° |
135.0° |
157.5° |
180.0° |
|
A vessel heading NNE is on a course of __________. |
022.5° |
045.0° |
067.5° |
090.0° |
|
A vessel heading SW is on a course of __________. |
202.5° |
225.0° |
247.5° |
270.0° |
|
A vessel heading WNW is on a course of __________. |
270.0° |
292.5° |
315.0° |
337.5° |
|
A vessel heading SE is on a course of __________. |
112.5° |
180.0° |
135.0° |
157.5° |
|
A vessel heading ENE is on a course of __________. |
022.5° |
045.0°
|
067.5 |
090.0° |
|
A Doppler log in the volume reverberation mode indicates __________. |
speed
through the water |
speed
being made good |
the
set of the current |
the
depth of the water |
|
A Doppler speed log indicates speed through the water __________. |
at
all times |
only
when there is no current |
in
the bottom return mode |
in
the volume reverberation mode |
|
A Doppler speed log indicates speed over ground __________. |
in
the bottom return mode |
in
the volume reverberation mode |
only
when there is no current |
at
all times |
|
A Doppler log in the bottom return mode indicates the __________. |
bottom
characteristics |
speed
over the ground |
velocity
of the current |
depth
of the water |
|
What will NOT induce errors into a Doppler sonar log? |
Roll |
Increased
draft |
Change
in trim |
Pitch |
|
You have replaced the chart paper in the course recorder. What is NOT required
to ensure that a correct trace is recorded? |
Adjust
the chart paper to indicate the correct time |
Set
the zone pen on the correct quadrant |
Test
the electrical gain to the thermograph pens |
Line
the course pen up on the exact heading of the ship |
|
If the electronic chart is part of an ECDIS, it must display the minimum
data required by IMO/IHO, to include all of the following EXCEPT __________. |
hydrography |
aids
to navigation |
regulatory
boundaries |
tidal
currents |
|
Which of the following must the electronic chart of an ECDIS display, as
required by IMO/IHO? |
Hydrography |
Regulatory
boundaries |
Ferry
routes |
All
of the above. |
|
ECDIS units incorporate Digital Chart Data Formats, which include __________. |
vector
and raster |
raster
only |
vector
only |
imposed
viewing |
|
Raster-scan chart data is __________. |
a
digitized "picture" of a chart in one format and one layer |
the
only format recognized by IMO/IHO |
organized
into many separate files |
composed
of files that are smaller than vector files |
|
Which of the following are data layer categories to be displayed on ECDIS? |
ECDIS
warnings and messages |
Notice
to Mariners information |
Hydrographic
Office data |
All
of the above. |
|
Which of the following data layer categories is NOT displayed on ECDIS? |
Hydrographic
Office data |
ECDIS
warnings and messages |
Notice
to Mariners information |
Ship
hydrodynamic information |
An ECDIS is required to display which information?
|
Hydrographic
data
|
ARPA
vectors
|
Radar
targets
|
All
of the above. |
|
An ECDIS is required to display which information? |
Meteorological
data |
Soundings |
Waypoints |
Radar
targets |
|
An ECDIS is required to display which information? |
Speed
of advance
|
Climatology
data
|
Depth
contours |
Water
temperature |
|
The database resulting from (1) the transformation of the electronic navigational
chart (ENC) by ECDIS for appropriate use, (2) the updates to the ENC by
appropriate means, and (3) the additional data added by the mariner, is
called the __________. |
display
base information |
chart
display information |
standard
display information |
system
electronic navigational chart |
|
The database information that should be shown when a chart is first displayed
on ECDIS is the __________. |
chart
display information
|
standard
display information
|
display
base information
|
system
electronic nautical chart |
|
The level of database information which cannot be removed from the ECDIS
display and consists of information which is required at all times in all
geographic areas and under all circumstances is the __________. |
system
electronic nautical chart |
chart
display information |
standard
display information |
display
base information |
|
Chart information details to be used in ECDIS should be the latest edition
of information originated by a government-authorized hydrographic office
and conform to the standards of (the) __________. |
NASA |
International
Maritime Organization |
US
Coast Guard |
International
Hydrographic Organization |
|
ECDIS must give an alarm for which of the following cases? |
If
the ship, within a specified time set by the watch officer, is going to
cross the boundary of a prohibited area |
When
the specified limit for deviation from the planned route is exceeded |
If
the ship, within a specified time set by the watch officer, is going to
cross a safety contour |
All
of the above. |
|
ECDIS must give an alarm for which of the following cases? |
If
the ship is going to reach a critical point on the planned route |
When
the speed of a dangerous target exceeds a set limit |
If
the ship's ETA has changed beyond the set limit |
All
of the above. |
|
ECDIS must give an alarm for which of the following cases? |
When
the speed of a dangerous target exceeds a set limit |
When
the specified limit for deviation from the planned route is exceeded |
If
the ship's ETA has changed beyond the set limit |
None
of the above |
|
ECDIS must have the capability to preserve the record of the voyage track
for the previous __________. |
4
hours |
6
hours |
12
hours |
24
hours |
Which data must ECDIS be able to record at one-minute intervals?
|
Position |
Course
made good history |
Electronic
navigational chart source |
All
of the above. |
|
Which data must ECDIS be able to record at one-minute intervals? |
Course
made good history |
Speed
through the water |
Estimated
time of arrival |
Shaft
RPM |
|
Which of the following must an ECDIS system be able to perform? |
Conversion
of "graphical coordinates" to "display coordinates" |
Transformation
of local datum to WGS-'84 datum |
Calculation
of true azimuth and distance between two geographical points |
All
of the above. |
|
ECDIS must be able to perform all of the following EXCEPT __________. |
determine
magnetic compass deviation |
convert "graphical
coordinates" to "display coordinates" |
determine
true bearing and distance between two geographical points |
transform
a local datum to the WGS-'84 datum |
|
What will cause the Electronic Plotting Aid (EPA) to emit a visual alarm,
audible alarm, or both? |
A
tracked target entering your preset CPA-TCPA limits |
A
target being initially detected within a guard zone |
A
tracked target lost for one radar scan |
An
acquired target entering into a guard zone |
|
An Electronic Plotting Aid (EPA) will drop off a target's vector if more
than __________ minutes elapse between each manual plot. |
3
|
2
|
6
|
10 |
|
What option does an Electronic Plotting Aid (EPA) not have? |
Trial
Maneuver |
Preset
CPA/TCPA |
Dual
VRMs/EBLs |
Target
Trails |
|
Vessel required to have an Electronic Plotting Aid (EPA) must have a device
to indicate the __________. |
speed
of the vessel over the ground or through the water |
vessel's
position |
depth
of the water |
relative
heading |
|
How many targets can an Electronic Plotting Aid (EPA) track at the same
time? |
2
|
20
|
5
|
10 |
|
Your Electronic Plotting Aid (EPA) has automatic speed inputs from the log.
Due to currents, the log is indicating a faster speed than the speed over
the ground. What should you expect under these circumstances? |
The
targets true course vector will be in error. |
The
generated CPA will be less than the actual CPA. |
The
range of initial target acquisition will be less than normal. |
The
generated TCPA will be later than the actual TCPA. |
|
Which Electronic Plotting Aid (EPA) data should you use in order to determine
if a close quarters situation will develop with a target vessel? |
Predicted
time of the closest point of approach (CPA) |
Initial
range of acquisition |
Vessel's
true vector indicates vessel will cross your heading |
Relative
track information |
|
When using an Electronic Plotting Aid (EPA), what should you consider in
order to evaluate the information displayed? |
Navigational
constraints may require a target vessel to change course. |
The
trial maneuver feature will automatically determine a course that will clear
all targets. |
The
target vessel's generated course and speed are based solely on radar inputs. |
You
cannot determine if a small target has been lost due to sea return. |
|
Your Electronic Plotting Aid (EPA) has two guard zones. What is the purpose
of the inner guard zone? |
Alert
the watch officer that a vessel is approaching the preset CPA limit |
Warn
of small targets that are initially detected closer than the outer guard
zone |
Sound
an alarm for targets first detected within the zone |
Guard
against target loss during critical maneuvering situations |
|
Electronic Plotting Aid (EPA) has which built in functions? |
Plots
at least 10 targets at one time |
Time
of closest point of approach (TCPA) |
Target
trails |
All
of the above. |
|
Electronic Plotting Aid (EPA) has which built in functions? |
Target
CPA and time of CPA (TCPA) |
Trial
maneuvering |
Automatic
target tracking |
Plots
at least 20 targets simultaneously |
|
When using the Electronic Plotting Aid (EPA) in heavy rain, which action
should you take? |
Navigate
as though the effective range of the radar has been reduced. |
Increase
the STC setting to reduce close-in spurious signals. |
Increase
the radar gain to pick up weak echoes through the rain. |
Increase
the range of the inner and outer guard rings. |
|
The speed of sound through ocean water is nearly always __________. |
faster
than the speed of calibration for the fathometer, unless the water is very
warm |
faster
than the speed of calibration for the fathometer |
the
same speed as the speed of calibration for the fathometer |
slower
than the speed of calibration for the fathometer |
|
When operated over a muddy bottom, a fathometer may indicate __________. |
a
zero depth reading |
a
shallow depth reading |
no
depth reading |
two
depth readings |
|
Which factor has the greatest effect on the amount of gain required to obtain
a fathometer reading? |
Type
of bottom |
Salinity
of water |
Atmospheric
pressure |
Temperature
of water |
|
The speed of sound in water is approximately __________. |
1.5
times its speed in air |
2.5
times its speed in air |
3.5
times its speed in air |
4.5
times its speed in air |
When using an echo sounder in deep water, it is NOT unusual to __________.
|
have
to recalibrate every couple of days due to inaccurate readings
|
receive
false echoes at a constant depth day and night
|
receive
a strong return at about 200 fathoms (366 meters) during the day, and one
nearer the surface at night |
receive
a first return near the surface during the day, and a strong return at about
200 fathoms (366 meters) at night |
|
If a sound signal is emitted from the oscillator of a fathometer, and two
seconds elapse before the returning signal is picked up, what depth of water
is indicated? |
824
fathoms |
1048
fathoms |
1248
fathoms |
1648
fathoms |
|
When using a recording depth finder in the open ocean, what phenomena is
most likely to produce a continuous trace that may not be from the actual
ocean bottom? |
Poor
placement of the transducer on the hull |
Multiple
returns reflected from the bottom to the surface and to the bottom again |
Echoes
from schools of fish |
Echoes
from a deep scattering layer |
|
What should you apply to a fathometer reading to determine the depth of
water? |
Add
the draft of the vessel. |
Subtract
the sea water correction. |
Subtract
the draft of the vessel. |
Add
the sea water correction. |
|
All echo-sounders can measure the __________. |
average
depth from waterline to hard bottom |
actual
depth of water below keel |
average
depth of water to soft bottom |
actual
depth of water |
|
An electronic depth finder operates on the principle that __________. |
radio
signals reflect from a solid surface |
pressure
increases with depth |
sound
waves travel at a constant speed through water |
radar
signals travel at a constant speed through water |
|
The recording fathometer produces a graphic record of the __________. |
depth
underneath the keel against a time base |
depth
of water against a distance base |
contour
of the bottom against a distance base |
bottom
contour only up to depths of 100 fathoms |
|
In modern fathometers the sonic or ultrasonic sound waves are produced electrically
by means of a(n) __________. |
transmitter |
transducer |
amplifier |
transceiver |
|
When using GPS without Selective Availability, you may expect your horizontal
accuracy to be better than __________. |
3
meters |
20
meters |
100
meters |
200
meters |
|
When navigating using GPS, what is an indicator of the geometry of the satellites
that your receiver is locked onto? |
Selective
Availability |
Precision
Coding |
Doppler
Shifting |
Horizontal
Dilution of Precision |
When using GPS, how many theoretical position lines are required for a two-dimensional
fix?
|
1
|
2
|
3 |
4 |
|
Which theoretical minimum number of measurements from satellites does a
GPS receiver need in order to provide an exact three-dimensional position? |
Five |
Four |
Three |
Two |
|
With regard to GPS, a civilian receiver may be capable of achieving the
same accuracy as a military receiver if __________. |
the
horizontal dilution of precision is high |
the
satellites are all below 15° in elevation |
your
vessel is equipped with a Doppler receiver |
selective
availability is set to zero |
|
Which feature, when set to zero, might allow a GPS unit to have an accuracy
equivalent to Precise Positioning Service receiver capability? |
Selective
Availability |
Anti-spoofing |
Auto-correlation
|
Transit |
|
The highest level of commercial navigational accuracy is provided by __________. |
NAVSAT,
using the Doppler-shift |
DGPS,
within a coverage area |
PPS,
without selective availability |
SPS,
without selective availability |
|
A low HDOP (Horizontal Dilution of Precision) number such as 2 indicates
a __________. |
poor
signal quality |
good
signal quality |
good
fix |
poor
fix |
|
Which statement concerning GPS is TRUE? |
It
cannot be used in all parts of the world. |
Two
position lines are used to give a 2D fix. |
There
are 12 functioning GPS satellites at present. |
It
may be suspended without warning. |
|
Most GPS receivers use the Doppler shift of the carrier phase to compute
__________. |
Time |
Longitude |
Latitude |
Speed |
|
Which type of GPS receiver has at least four channels to process information
from several satellites simultaneously? |
Sequential |
Multiplex |
Continuous |
None
of the above |
|
What does not contribute to the commercial GPS receiver position error? |
Satellite
clock |
Atmospheric/Ionospheric
propagation |
Satellites'
orbits |
Ship's
speed |
|
With respect to failure warnings and status indications, GPS receivers should
provide, at a minimum, __________. |
an
indication within 5 seconds if the specified HDOP has been exceeded |
a
differential GPS status indication of the receipt of DGPS signals |
a
warning of loss of position |
All
of the above. |
|
With respect to failure warnings and status indications, GPS receivers should
provide, at a minimum, __________. |
a
cross-track error alarm |
an
indication of a change in satellite configuration |
an
alarm if engine speed is suddenly reduced |
a
warning of loss of position |
|
A hand held instrument used to measure distances between objects and the
ship is a __________. |
hygrometer |
vernier |
psychrometer |
stadimeter |
|
Illustration D011NG below represents the geographic location of a vessel
and the radar presentation at the same time. Which statement is TRUE? |
The
small island is not detected due to the effect of beam width. |
Ship
No. 2 is not detected due to the reflective mass of the background mountain
overpowering the ship's reflective signals. |
Ship
No. 1 is not detected due to the shadow effect of the headland. |
A
tangent bearing of the headland to the south-southeast should be corrected
by adding one-half of the beam width. |
|
You are radar scanning for a buoy fitted with a racon. In illustration D017NG
below, which radar screen represents the presentation you should expect
on the PPI? |
A |
B |
C |
D |
When using the radar for navigating __________.
|
the
best fix is obtained by using a tangent bearing and a range
|
and
using two radar ranges for a fix, the objects of the ranges should be close
to reciprocal bearings
|
and
crossing a radar range of one object with the visual bearing of a second
object, the two objects should be 80° to 110° apart
|
and
using ranges, the most rapidly changing range should be measured first |
|
Illustration D011NG below represents the geographic location of a vessel
and the radar presentation at the same time. Which statement is TRUE? |
A
tangent bearing of the headland to the south-southeast is corrected by subtracting
one-half of the beam width. |
Ship
No. 2 is not detected due to the side lobe effect of radar reflecting from
the mountain. |
Ship
No. 1 does not appear as an individual target due to the effect of beam
width. |
Small
island is not detected due to the multiple echo effect from the mountain. |
|
You are enroute to assist vessel A. Vessel A is underway at 6 knots on course
133°T, and bears 042° at 105 miles from you. What is the course to steer
at 10 knots to intercept vessel A? |
063° |
068° |
073° |
079° |
|
You are approaching a light fitted with a RACON. The light may be identified
on the radar by __________. |
a
coded signal appearing on the same bearing at a greater range than the light |
a
dashed line running from the center of the scope to the light |
an
audible signal when the sweep crosses the light |
a
circle appearing on the scope surrounding the light |
|
You are enroute to assist vessel A. Vessel A is underway at 5 knots on course
063°T, and bears 136°T at 78 miles from you. What is the course to steer
and running time at 13 knots to intercept vessel A? |
158°,
7h 20m |
115°,
7h 20m |
158°,
5h 45m |
115°,
5h 45m |
|
You are enroute to assist vessel A. Vessel A is underway at 5.5 knots on
course 033°T, and bears 284°T at 43 miles from you. What is the course to
steer and running time at 16 knots to intercept vessel A? |
265°,
2h 32m |
303°,
3h 13m |
265°,
3h 13m |
303°,
2h 32m |
|
You are approaching a sea buoy which emits a racon signal. This signal is
most frequently triggered by which type of radar? |
10
cm |
3
cm |
Both
3 cm and 10 cm |
Signal
does not depend on radar type. |
|
In order to insure that the racon signal is visible on your 3 cm radar,
the __________. |
rain
clutter control should be off but, if necessary, may be on low |
gain
control should be turned to maximum |
radar
should be stabilized, head up |
10
cm radar should be placed on standby or turned off |
|
You are enroute to assist vessel A. 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 and running time at 13 knots to intercept vessel A? |
274°,
7h 37m |
254°,
8h 35m |
254°,
7h 37m |
274°,
8h 35m |
|
You are enroute to assist vessel A. Vessel A is underway at 4.5 knots on
course 233°T, and bears 346°T at 68 miles from you. What is the course to
steer at 13 knots to intercept vessel A? |
323° |
314° |
327° |
318° |
|
You are enroute to assist vessel A. Vessel A is underway at 5.5 knots on
course 033°T, and bears 248°T at 64 miles from you. What is the course to
steer at 13 knots to intercept vessel A? |
262° |
269° |
276° |
281° |
|
You are enroute to assist vessel A. Vessel A is underway at 6 knots on course
133°T, and bears 343°T at 92 miles from you. What is the course to steer
at 9 knots to intercept vessel A? |
356° |
022° |
038° |
003° |
|
You are enroute to assist vessel A. Vessel A is underway at 6 knots on course
133°T, and bears 042°T, 105 miles from you. What is the time to intercept
if you make 10 knots? |
12h
30m |
12h
44m |
12h
58m |
13h
22m |
|
You are enroute to assist vessel A. Vessel A is underway at 6 knots on course
133°T, and bears 343°T at 92 miles from you. What is the time to intercept
if you make 9 knots? |
6h
43m |
6h
08m |
7h
12m |
7h
44m |
|
You are enroute to assist vessel A. Vessel A is underway at 4.5 knots on
course 233°T, and bears 264°T, 68 miles from you. What is the time to intercept
if you make 13 Knots? |
6h
31m |
6h
47m |
7h
03m |
7h
37m |
|
You are enroute to assist vessel A. Vessel A is underway at 5.5 knots on
course 033°T, and bears 248°T at 64 miles from you. What is the time to
intercept if you make 13 knots? |
4h
36m |
4h
55m |
3h
59m |
3h
44m |
|
You are enroute to assist vessel A. Vessel A is underway at 5.5 knots on
course 033°T, and bears 284°T, 43 miles from you. What is the time to intercept
if you make 16 knots? |
2h
16m |
2h
22m |
2h
32m |
2h
42m |
|
Coral atolls, or a chain of islands at right angles to the radar beam, may
show as a long line rather than as individual targets due to __________. |
the
multiple-target resolution factor |
the
pulse length of the radar |
the
effects of beam width |
limitations
on range resolution |
|
The signal from a ramark will show on the PPI as a __________. |
dashed
circle at the same range as the transponder |
circle
surrounding the transponder |
radial
line from the transponder to the center of the PPI |
coded
signal on the same bearing and at a greater range then the transponder |
|
A radar display which is oriented, so that north is always at the top of
the screen, is called a(n) __________. |
relative
display |
stabilized
display |
composite
display |
unstabilized
display |
|
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? |
Compass |
Relative |
Magnetic |
TRUE |
|
Your radar is set on a true motion display. Which of the following will
appear to move across the PPI scope ? |
Echo
from a ship at anchor |
Own
ship's marker |
Echoes
from land masses |
All
of the above. |
|
Your radar displays your ship off center. As you proceed on your course,
your ship's marker moves on the PPI scope while echoes from land masses
remain stationary. What is this display called? |
Off
center |
True
motion |
Head
up
|
Stabilized |
|
Your radar has a beam width of 2°. The radar gyro bearing of the right tangent
of an island is 316°. The gyro error is 1°E. Which true bearing should be
plotted on the chart? |
313° |
314° |
316° |
317° |
|
The beam width of your radar is 2°. The left tangent bearing of a small
island, as observed on the PPI scope, is 056°pgc. If the gyro error is 2°E,
what bearing would you plot on the chart? |
052° |
056° |
059° |
060° |
|
The radar control used to reduce sea return at close ranges is the __________. |
sensitivity
time control |
pulse
length control |
fast
time constant |
gain
control |
|
When you turn on the fast time constant (differentiator) control of a radar
it will __________. |
only
suppress weak targets to a limited distance from the ship (sea clutter) |
reduce
clutter over the entire PPI by shortening the echoes |
reduce
the beam width to provide a map-like presentation for navigation |
enhance
weak target echoes and brighten them on the PPI |
|
The radar control that shortens all echoes on the display and reduces clutter
caused by rain or snow is the __________. |
fast
time constant (differentiator) |
sensitivity
time control (sea clutter control) |
brilliance
control |
receiver
gain control |
|
The radar control that reduces weak echoes out to a limited distance from
the ship is the __________. |
sensitivity
time control (sea-clutter control) |
fast
time constant (differentiator) |
brilliance
control |
receiver
gain control |
|
Radar makes the most accurate determination of the __________. |
distance
to a target |
direction
of a target |
size
of a target |
shape
of a target |
|
What is the approximate wave length of an X Band Radar operating on a frequency
of approximately 9500 MHz? |
3
cm |
10
cm |
30
cm |
100
cm |
|
You have another ship overtaking you close aboard to starboard. You have
3 radar targets bearing 090° relative at ranges of .5 mile, 1 mile, and
1.5 miles. In this case, the unwanted echoes are called __________. |
side-lobe
echoes |
indirect
echoes |
multiple
echoes |
spoking |
|
An indirect radar echo is caused by a reflection of the main lobe of the
radar beam off the observer's vessel. Which of the following is NOT a characteristic
of indirect echoes? |
When
plotted, their movements are usually abnormal. |
They
always appear on a bearing of 90° from the true bearing of the contact. |
The
indirect echoes usually appear in shadow sectors. |
Their
bearing is almost constant, even when the true bearing of the contact changes
appreciably. |
|
Your radar indicates a target; however, there is no visible object at the
point indicated. A large mountain, approximately 50 miles away on the same
bearing as the target, is breaking the horizon. You should suspect the radar
target is caused by __________. |
ducting |
sub-refraction |
ionospheric
skip waves |
a
submerged submarine |
|
You have been observing your radar screen and notice that a contact on the
screen has remained in the same position, relative to you, for several minutes.
Your vessel is making 10 knots through the water. Which statement is TRUE? |
The
contact is dead in the water. |
The
radar is showing false echoes and is probably defective. |
The
contact is on a reciprocal course at the same speed as your vessel. |
The
contact is on the same course and speed as your vessel. |
|
Which of the four adjustable errors in the sextant is the principle cause
of index error? |
Telescope
not being parallel to the frame
|
Index
mirror and horizon glass not being parallel
|
Horizon
glass not being perpendicular to the frame
|
Index
mirror not being perpendicular to the frame |
In what order should the following sextant adjustments be made?
{{{
I. Make telescope parallel to frame of sextant.
II. Set horizon glass perpendicular to frame of sextant.
III. Make index mirror and horizon glass parallel when index arm is set
at zero.
IV. Set index mirror perpendicular to frame of sextant.}}} |
III,
II, IV, I |
IV,
II, III, I |
I,
II, III, IV |
I,
IV, II, III |
|
The part of a sextant mounted directly over the pivot of the index arm is
the __________. |
micrometer
drum |
index
mirror |
horizon
glass |
telescope |
|
When the index and horizon mirrors of a properly adjusted sextant are at
an angle of 45° to each other, the arc reads __________. |
22
1/2° |
45° |
60° |
90° |
|
Which of the four adjustable errors in the sextant causes side error? |
Index
mirror not being perpendicular to the frame |
Horizon
glass not being perpendicular to the frame |
Elliptical
centering error |
Telescope
not being parallel to the frame |
|
What causes the error of collimation with regards to the four adjustments
to a sextant? |
Telescope
not parallel to the frame |
The
frame and horizon glass not perpendicular |
Personal
error |
The
frame and index mirror not perpendicular |
|
The horizon glass of a sextant is __________. |
silvered
on its half nearer the frame |
between
the horizon and the shade glasses |
mounted
on the index arm |
All
of the above. |
|
There are seven sources of error in the marine sextant. Of the four errors
listed, which one is adjustable? |
Error
of collimation |
Prismatic
error |
Centering
error |
Graduation
error |
|
Which is a nonadjustable error of the sextant? |
Error
of perpendicularity |
Centering
error |
Side
error |
Error
of collimation |
|
Because of the reflecting properties of a sextant, if the sextant altitude
reads 60° on the limb, the actual arc of the limb from 0° to the 60° reading
is __________. |
20° |
30° |
40° |
60° |
|
For a well made and well maintained sextant, the maximum value of which
correction is usually so small that it can be ignored? |
Dip
correction |
Instrument
correction |
Personal
correction |
Phase |
A sextant having an index error that is "on the arc" has a __________.
|
semidiameter
error
|
dip
error
|
positive
correction
|
negative
correction |
|
A sextant having an index error that is "off the arc" has a __________. |
dip
error |
semidiameter
error |
positive
correction |
negative
correction |
|
The marine sextant is subject to seven different types of errors, four of
which may be corrected by the navigator. An error NOT correctable by the
navigator is __________. |
index
error |
prismatic
error |
perpendicularity
of the horizon glass |
perpendicularity
of the index mirror |
|
What is a nonadjustable error of the sextant? |
Side
error |
Prismatic
error |
Error
of collimation |
Index
error |
|
In order to remove index error from a sextant, you should adjust the __________. |
horizon
glass to make it parallel to the sextant frame |
telescope
to make it perpendicular to the sextant frame |
index
mirror to make it parallel to the horizon glass with the index set at zero |
horizon
glass to make it parallel to the index mirror with the index set at zero |
|
Which of these sextant errors is nonadjustable? |
Prismatic
error |
Centering
error |
Graduation
error |
All
of the above. |
|
Index error of a sextant is primarily caused by __________. |
improperly
correcting the other errors in a sextant |
the
horizon glass not being parallel to the horizon mirror |
the
horizon glass not being parallel to the index mirror |
human
error in taking a celestial observation |
|
The index error is determined by adjusting the __________. |
horizon
glass |
micrometer
drum |
index
mirror |
sextant
frame |
|
A marine sextant has the index arm set at zero and the reflected image of
the horizon forms a continuous line with the actual image. When the sextant
is rotated about the line of sight the images separate. The sextant has
__________. |
prismatic
error |
error
of perpendicularity |
side
error |
centering
error |
|
In order to remove side error from a sextant, you should adjust the __________. |
horizon
glass to make it perpendicular to the sextant frame |
telescope
to make it parallel to the sextant frame |
horizon
glass to make it perpendicular to the index mirror with the index set at
zero |
horizon
glass to make it parallel to the horizon mirror with the index set at zero |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ships fog horn 5.5 seconds after the signal was sounded. What is
the distance to the shore? |
3825
ft (1166 meters) |
3072
ft (936 meters) |
3450
ft (1052 meters) |
2475
ft (754 meters) |
|
You are approaching Chatham Strait from the south in foggy weather. You
have Coronation Island and Hazy Islands on the radar. Suddenly the radar
malfunctions. You then resort to using whistle echoes to determine your
distance off Coronation Island. Your stopwatch reads 16.3 seconds for the
echo to be heard. How far are you off Coronation Island? |
1.0
mile |
1.5
miles |
2.0
miles |
2.5
miles |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ships fog horn 6 seconds after the signal was sounded. What is the
distance to the shore? |
1100
yards |
1000
yards |
900
yards |
1200
yards |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ship's fog horn 4 1/2 seconds after the signal was sounded. What
is the distance to the shore? |
405
yards |
628
yards |
730
yards |
825
yards |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ship's fog horn 4 seconds after the signal was sounded. What is the
distance to the shore? |
209
yards |
363
yards |
480
yards |
730
yards |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ship's fog horn 3 seconds after the signal was sounded. What is the
distance to the shore? |
872
yards |
792
yards |
550
yards |
1100
yards |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ships fog horn 2 1/2 seconds after the signal was sounded. What is
the distance to the shore? |
225
yards |
460
yards |
750
yards |
910
yards |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ships fog horn 2 seconds after the signal was sounded. What is the
distance to the shore? |
320
yards |
140
yards |
360
yards |
280
yards |
|
While navigating in fog off a coastline of steep cliffs, you hear the echo
of the ships fog horn 3 1/2 seconds after the signal was sounded. What is
the distance to the shore? |
315
yards
|
640
yards
|
480
yards
|
143
yards |
