Navigation Flashcards
What is a circle?
Visual Fix
What is a triangle?
Electronic Fix
What is a square?
Estimated Position
What is a half moon?
Dead Reckoning
What is a circle w/ dot in the middle?
Visual reference without previous fix data.
Sailing Chart scale?
1:600,000
General Chart scale?
1:150,000 - 1:600,000
Coastal chart scale?
1:50,000 - 1:150,000
Harbor chart scale?
1:50,000 - larger
Degrees of latitude are always ___ miles apart?
60NM
Distance between degrees of LONGITUDE are __NM at the equator.
60, but less further north or south.
Water level depth is measured at?
Mean Low tide
What is standard map projection style?
Mercator projection
Gnomonic Projection used for?
Navigation on the great circle
Stereographic projection used for?
Navigation in polar regions
NOAA charts sounding datum?
Indicated as Mean Lower Low Water (MLLW)
Letter for center of mo board?
“e”
Mo board letter for “own ship” course and speed?
“er”
Contacts direction and speed on mo board?
DRM and SRM
Vector representing contacts true course and speed on mo board?
“em” = them
What is least accurate type of fix?
Radar fix
One degree equals?
60 NM
What is course?
Intended direction of travel
What is heading?
ACTUAL direction vessel is traveling.
What is dead reckoning?
Approximate position by advancing a previous position accounting for course and speed.
What defines a nautical mile?
Equal to 1 minute of latitude.
How many degrees of latitude?
0 degrees - 90 degrees North/South
How many degrees of longitude?
0 degrees - 180 degrees (East/ West)
60 minutes equals?
1 degree
Outermost circle on compass rose?
Oriented true north.
Innermost circle on compass rose?
Magnetic North.
Longitude is measured East/West of?
Prime Meridian (0-180 degrees)
Latitude is measured North or South of?
The equator (0-90 North/ South)
1 minute of latitude is?
1 NM
Title block section of a chart?
“SAPSSD”
Seal
Area covered by chart
Projection
Scale
Sounding information
Datum information
Interval between radar pulses?
Pulse repetition frequency
How does radar differentiate between two vessels on same bearing but different ranges?
Range resolution
What type of radar return is caused by ocean waves?
Sea return
All definitions showing chart symbols and abbreviations are contained in?
Chart No. 1
1NM is equal to how many feet/yards?
6080FT/2000YDS
Formula to calculate time?
D÷S=T
Formula to calculate speed?
D÷T=S
Formula to calculate distance?
SxT=D
X-Band Radar wavelength/Freq range?
3CM, 9300-9500Mhz
S-Band Radar wavelength/Freq range?
10CM, 2900-3100Mhz
The majority of marine radars operate within a range of?
400-4000 pulses per second
RACONS respond to what type of radars?
3 and 10 CM radars
Max range for RACON reception?
Limited by Line of Sight
What IALA regime does U.S. use?
IALA B
Topmost band of a cylindrical buoy is ALWAYS?
Green, when used as a lateral mark.
What is the topmost band of a conical buoy when used as a lateral mark?
Red
When returning from sea, a triangular shaped dayboard marks the?
Starboard side of the channel.
When returning from sea, a square shaped dayboard marks?
Port side of the channel.
Only ATON with green or red lights have?
Lateral significance.
Green lights mark?
Port side of channels.
Red lights mark?
Starboard side of channels.
International chart scale?
1:350,000-1:10,000,000
What are the 5 classifications of conventional nautical charts?
International, Sailing, General, Coastal, Harbor.
Difference between true and magnetic North is called?
Variation.
Soundings are measured as?
Feet, Fathoms, or Meters.
Edition number of a chart located?
Lower left hand corner of chart.
Slanted lettering on a chart is used to label?
Information affected by tidal changes/currents.
Vertical lettering on a chart is used to describe?
Information NOT affected by tidal changes/current.
What are the two types of electronic chart data?
Vector and Raster Charts.
How many satellites make up the GPS system?
24 satellites.
When there are only 2 LOP’s or ranges for a fix?
Quality of fix will be best when there is a 90 degree difference in the lines.
An ideal fix has 3 or more LOP’s intersecting at a single point. The LOP’s have a separation of?
At LEAST 60, but not more than 120 degrees.
Converting minutes into tenths of hours is done by?
Dividing minutes by 60.
Converting tenths of hours into minutes is done by?
Multiplying by 60.
CG Navigation Standards Manual requires that each fix be followed by a DR track of at least?
2 fix intervals.
What does “RADAR” stand for?
Radio detection and Ranging.
What is “wavelength” defined as?
Wavelength is the distance along the direction of propagation between successive crests or troughs.
What is “amplitude” defined as?
The max displacement of the wave from its mean or zero value.
What is “cycle” defined as?
A complete alternation or oscillation from one crest through a trough to the next crest.
What is “diffraction” defined as?
Diffraction is the bending of a wave as it passes through an obstruction.
What is “refraction” defined as?
Refraction is what affects the range at which objects are detected.
The minimum range at which a target can be detected is largely determined by?
The pulse length.
Because of the frequencies and power outputs required, the transmitter oscillator is a special type known as?
A Magnetron
The Prime Meridian passes through which town?
Greenwich, England.
Boat navigation is generally accomplished by plotting?
Rhumb lines on a Mercator chart.
What are the three types of small craft charts?
Folio, Pocket fold, Recreational charts.
The basic symbol for a buoy on a chart is?
Diamond and a small circle.
Variation is considered easterly if the compass needle is?
Aligned eastward(right) of True North.
Variation is considered westerly if the compass needle is?
Aligned westward(left) of True North.
“Track” is defined as?
Course followed or intended by a vessel.
“Set” is defined as?
The direction, expressed in degrees true, that the current is flowing.
“Drift” is defined as?
Speed of the current, usually stated in knots.
In COLREGS, what rule governs narrow channels?
Rule 9
In COLREGS, what rule governs Traffic Separation Schemes?
Rule 10
A vessel shall be deemed to be overtaking another vessel from a direction of?
22.5 degrees abaft the beam.
COLREGS Rule 13 governs?
Overtaking.
In COLREGS, what does Rule 14 cover?
Head on situations
In COLREGS, what does Rule 15 cover?
Crossing situations.
In COLREGS, what does Rule 18 cover?
Responsibilities of vessels.
In COLREGS, what does Rule 19 cover?
Vessels in restricted visibility.
Sternlight is what in degrees?
135 degrees
Sidelights are what in degrees?
112.5 degrees.
A Masthead light is what in degrees?
225 degrees.
Yellow buoys and beacons are called?
Special Marks.
Mercator projection is also known as?
Cylindrical projection
All NOAA charts use what for datum?
North American Datum of 1983 (NAD 83) or WGS 84