Miscellaneous Questions Flashcards
A chart suitable for inshore navigation, for entering bays and harbours, would have a scale of:
1:50,000 to 1:150,000
A composite great cirlce route is not as short a distance as a great circle route, but it is sometimes used instead. Why?
It avoids high latitudes where ice may be found
A free gyroscope is said to have “three degrees of freedom”. From those listed, which is NOT one of these?
Latitude axis
A gyro compass on a high-speed craft often takes time to settle correctly when altering course. What causes this problem?
The change in the (large) value of the latitude course and speed error when altering course
A light giving 4 flashes, which has sectors showing two different colours, could have an abbreviated description:
Fl(4) WR 15s 15m 12.10M
A position line on a chart is defined as a line:
somewhere on which the observer is situated
After all the adjustments have been made of the sextant, any remaining error is called:
index error
All gyro compasses, when on the eqautor, should have:
no latitude error
Apart from ensuring navigational safety at anchorage, what should the OOW do?
Monitor the VHF for orders for the vessel
At sunrise and sunset, the effect of atmospheric refraction is to:
reduce he sun’s apparent vertical diameter
At the summer solstice, the altitude of the sun at noon to an observer at the pole would be?
23.5°
At the winter solstice, the sun will not rise at all higher latitudes than:
66.5°
Charted depths are always measured below:
chart datum
Curves on chart showing values of equal variation are called:
Isogonic
Damping in azimuth in a gyro compass produces:
a setting position exactly on the meridian
Damping in tilt in a gyro compass produces:
an error which varies with latitude
Distance on a chart is measured using:
latitude sacle
Fiber-optic compasses have advantages over conventional gyro compasses. From those listed, which is NOT one of those advantages?
They are more accurate
For a circumpolar star, which from those listed is NOT true?
The LHA of the star will always be less than 90°
Free gyroscopes are turned into gyro compasses by utilizing:
gravity
From those listed which should be the preferred method position fixing for greatest accuracy and certainly of position?
taking a radar and visual bearing
From those listed, the best and target to use for a radar bearing is:
an isolated feature
From those listed, the best and target to use for radar ranging is a:
cliff face
From those listed, which are “ soft iron” corrector?
The spheres
From those listed, which is NOT a reason for having the standard magnetic compass high up and on the certerline in the ship?
In order to reduce the chance of damage
From those listed, which is NOT a way of destroying magnetism?
Placing another magnet next to it with unlike poles together
From those listed , which of the statement about magnetic variation is TRUE?
The value of variation at a place changes slowly
From those listed, which of the statement about the dip of a magnet is TRUE?
At the magnetic equator, the dip is zero and the directive force greatest
From those listed, which of the statement about the poles of a magnet is TRUE?
The red pole will attract a blue pole and is the north seeking end
From those lited, which would be the preferred method of position fixing for greatest accuracy and certainty of position?
Taking a radar range and visual bearing
Gaussin error of the magnetic compass is caused by:
the ships being on the same heading for a long period
Gaussin or Retentive error:
is uncertain in size and may take several hours to clear
Great circles appear as straight lines on:
gnomonic charts
Heeling error is at its maximum when the course are:
north or south
How are secondary port chosen to be linked with a particular standard port?
The standard port is is the nearest one with similar tidal characteristics
How does a current flowing in the same direction as the wind affect the sea wave length and height?
It increases ave length and decreases wave height
How is a ship’s permanent magnetism acquired during building?
By the hammering and heating processes while heading in the same direction in the building the yard
How is distance measured on a Mercator chart?
On the latitude scale
How many degrees are there in each point of the compass?
11.25
How often are chart correction published?
Weekly
How often is a chart catalogue published?
Annualy
How often should a position fix be taken during a sea voyage if the ship is in open coastal waters?
Atleast every 30 minutes
How often should the auto pilot be tested in manual mode?
At least once a watch
How often should the magnetic compass error be checked?
Once a watch and after a major course alteration
How should tidal predictions be made for stretches of coastline between Secondary Ports?
By using a co - tidal line chart
If a ship has a permanent magnetism with a blue pole forward, the deviation caused will be;
zero on north and south, east on easterly, west on westerly courses
If a ship has permanent magnetism with a blue pole to port, the deviation caused will be:
zero on east and west, west on northerly,east on southerly courses
If a ship has permanent magnetism wit a red pole forward, the deviation caused will be:
zero on north and south,west on easterly,east on westerly courses
If a ship is built a yard while heading south,the poles of permanent magnetism will be:
blue to the bow and red to the stern
If a ship is built in a yard while heading east, the poles of permanent magnetism will be:
red to port and blue to starboard
If a ship is built in a yard while heading north , the poles of permanent magnetism will be:
red to the bow and blue to the stern
If a star has a northerly declination and the observer is in north latitude,which of the statements listed is TRUE?
The star will be above the horizon for more than 12 hours
If the axis of a free gyroscope in a north latitude is horizontal and pointed to the east of north of the meridian,it will:
dry east and tilt up
If the axis of a free gyroscope on the equator is horizontal,the northerly end of the spin axis will:
tilt up if to the east of the meidian
If the OOW is in doubt as to the Pilot’s actions or Intentions,what must he do?
Seek clarification from the Pilot, notify the master and take corrective action
If the trace is not correctly centered,error may occur when:
measuring bearings
If the true transit bearing of two leading lights is red off the chart and the compass bearing of the two lights, when in transit,is taken,then the difference between the two bearings so obtained is the:
compas error
In an echo sounder, what converts the electrical signal into sound?
The transducer
In what direction does the axis of the gyro- compass wheel point?
True North
In which publication can information on ship reporting be found?
ALRS
In which publication can information on VTS be found?
ALRS
Incoming target echoes are detected by the:
mixer cyrstal
Latitude on the terrestrial sphere is comparable with what on the celestial sphere?
Declination
Latitude,course and speed error of a gyro compass:
applies to all gyro compasses
Magnetic compass deviation changes with:
heading
Magnetic variation changes its value with:
the vessel’s position on the earth
Marine radar wavelenghts are measured in:
centimeters
Most commonly,ship’s radar operates in the:
X- BAND
On the chart, to find the course to steer to make a good a course, allowing for current and leeway , the current and leeway would be applied:
current first, at the start of the run and then leeway
Over what length of time a diesel powered vessel should be slowed down from full sea -speed to maneuvering speed?
1 hour
Precession in relation to a free gycroscope is:
the change of dirction of the spin axis when a force is applies at right angles to the axis
Radar does not transmit continuously because it would:
prevent detection of targets
Radio signals travel a approximately a speed of:
300 milion meters per second
Secondary Ports associated with Standard Ports are classed in that way because:
the tidal curves are similar
Should the OOW, who is escorting the pilot to the pilot ladder, be equipped with a walkie-talkie for communication with the bridge?
Always
Sidereal hour angle is defined as the angular distance of an hour circle:
West of the First Point of Aries
Sounds waves will travel through:
gases, liquids and solids
Spring tides normally occur:
about every two weeks
Stars tabulated in the nautical almanac which have a negative magnitude (e.g. -1.4)?
Are very bright
The “ equation” of time” is
the interval between apparent time and mean time
The “ magnetic variation” is the angle between:
the geographic and magnetic meridians
The angle between the magnetic north and the true north is :
Variation
The axis of a free gyroscope is pointed at a star. From those listed, which is not correct?
The axis cannot be distributed from this direction while the rate of spin is maintained
The chart abbreviation “Al Fl WR 60 secs” indicates:
a white flash followed immediately by a red flash every 60 seconds
The commonest use of the ABC tables is to find the azimuth of a celestial body. These tables can also be used to:
find the initial course in a great circle sailing calculation
The correction of atmospheric refraction as applied to the observed altitude of a body:
decreases with altitude
The declination of a celestial body is the:
arc of the celestial meridian between the equinoctial and the parallel of declination passing through the body
The deviation of a compass produced by a disturbing magnet varies:
inversely with the cube of the distance from the magnet
The earth is said to be in “aphelion” on approximately:
4th July
The earth is said to be in “perihelion” on approximately:
1st January
The effect of gravity control makes the axis of the gyroscope:
move anti-clockwise around a central position in an ellipse
The first point of Aries is the point on the celestial sphere where:
the ecliptic cuts the equinoctial on the sun’s apparent path from south to north
The free gyroscope are turned into gyro compasses by utilizing:
gravity
The frequency of a radio wave is:
the number if wavelengths which pass a given point in one second
The GPS system uses satellites which:
circle on earth approximately twice each day in a precise orbit
The GPS system uses:
UHF radio signals
The horizontal distance between the adjacent crest of a radio wave is called:
the wavelength
The intensity of the election beam in the C.R.T. is controlled by:
varying the potential on the grid
The intermediate frequency is generated by the:
mixer crystal
The magnetic equator is:
the line joining places where the dip is zero
The magnetic force exerted at any point in the magnetic field varies:
inversely with the square of the distance from the magnet
The magnitude of a star is a measure of its:
Relative brightness
The magnitude of a star which can only just be seen with the naked eye on a clear, dark night is:
6th magnitude
The main source of error in a GPS position would be from:
Satellite clock error
The moon rotates around the earth approximately:
28 days
The moon spins on its axis approximately every:
28 days
The most appropriate chart for navigating when approaching a harbour is:
a large scale chart
The path of the moon’s rotation around the earth, relative to the plane of the earth rotation the sun is:
at an angle of 5°
The path of the earth’s rotation around the sun, relative to the plane of the equator is:
at an angle of 23.5°
The period of a semi-diurnal tide is approximately:
half a lunar day
The plane of the index mirror of the sextant is at an angle of 20° to the plane of the horizon mirror. What is the reading on the arc?
40°
The point at which the helm must be applies to achieve a required course alteration is called the:
wheel-over position
The principle of a fiber-optic “gyro” compass relies on:
three fiber-optic rings, mounted on a platform, which sense the rotations of the platform due to ship and earth movement
The process of turning a gravity controlled gryroscope into a compass is called:
damping
The relationship between the distance on the earth and the length by which that distance is shown on the navigational chart is called the:
natural scale
The ship’s magnetic compass should be adjusted following certain circumstances. From those listed, which is NOT one of those circumstances?
When a new Master joins the ship
The ship’s magnetic compass should be especially checked for error following certain circumstances. From those listed, which is not one of those circumstances?
If the ship has visited an areas with a large value of variation
The shortest distance between two points on the earth’s surface is:
An arc of a great circle
The sidereal hour angle of a celestial body is the:
arc of the equinoctial (measured westwards from the first point of Aries) to the celestial meridian through the body
The summer solstice in the northern hemisphere is approximately on:
21st June
The summer solstice in the southern hemisphere is approximately on:
21st December
The sun is at the first point of Aries on the celestial sphere at approximately:
21st March
The times of sunrise and sunset are tabulated in the Nautical Almanac. These times are:
The LMT when the upper limb is on the visible horizon for an observer at sea level
The two unique properties of a free gyroscope are:
precession and gyroscopic inertia
The unit which sends returning target echoes to the receiver is the:
scanner unit
The value of the “equation of time” is:
between zero and about 17 minutes
The vertex of a great circle is the point at which it:
comes nearest to the pole
The vertical force of the earth’s magnetism:
does not cause deviation of the magnetic compass
The vessel is on a steady bearing and the range is reducing. What action would you take?
sound two short blasts and alter course to port
To an observer at the south pole, at the beginning of September:
there will be twilight throughout the day
To convert a compass course to a magnetic course, it is necessary to apply:
deviation
To convert a magnetic course to a true course, it is necessary to apply:
variation
Under soundings marked on the chart, the nature of the sea bottom is also indicated. What does SH indicate?
Shells
Variation values change for a particular place because:
the magnetic poles are moving their positions in relation to the geographic poles
What are sailing directions also known as?
Pilot books
What chart should be used when navigating?
The largest scale chart onboard for the area which is properly corrected
What charts are used for coasting, pilotage waters and plotting waypoints?
Large scale
What charts are used for plotting Great Circle course?
Gnomonic
What do you call the error in the observed altitude of the sun, which results from the observer being on the surface of the earth not at its center?
Parallax
What is “side error” on a marine sextant?
When the horizon glass/mirror is not perpendicular to the plane of the sextant
What is mean by “retentive magnetism” with regard to a ship’s magnetic compass?
The ship retains induced magnetism if the ship has been heading in the same direction for a considerable period
What is the “error or collimation” on a marine sextant?
When the telescope is not parallel to the plane of the sextant
What is the “error of perpendicularity” on a marine sextant?
When the index mirror is not perpendicular to the plane of the sextant
What is the angle between the ecliptic and equinoctial?
23.5°
