by mags

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What are the 4 divisions of navigation?
celestial navigation
electronic navigation
Dead Reckoning
process of projecting the position of the vessel at any given momentby applying the last determined position or fix of the ships run
DR position is determined using only what?
ships true course ang engine ordered speed
Estimated Position
determined using estimated effects of set and drift
determing position of the vessel by frequent reference to landmarks, atons, and depth soundings
Celestial Navigation
determing ships position by astronomical observations
Electronic navigation
includes radio, radar and GPS to establish a position
What are the 4 phases of navigation?
inland waterways (ICW, rivers, channels estuaries)

harbor & harbor approach

ocean (outside 50 NM) 

coastal(within 50 NM of the coast or inshore of the 200 meter contour)
Equatorial diameter
approx 6887.91NM
Polar diameter
approx 6864.57 NM
Great Circle
line of intersection of a sphere and a plane through its center
Small Circle
line of intersection of a sphere and a plane that does not pass the center
great circlles that pass through the geographical poles of the earth
small circle whose plane is parallel to the plane of the equator
Rhumb line
a line making the same oblique angle with all meridians forming a loxodromic curve or loxodorme
Great Circle Distance
distance along a great circle connecting two points
distance between two meridians at any parallel of latitude
What is the distance of a nautical mile in feet?
6,076.1 feet
What are the two types of compasses?
Azimuth Circle
measures bearing and azimuths of terrestrial and celestial objects
Bearing Circle
measures the bearing of terrestrial objects
Telescopic Alidade
provides greater accuracy of bearing azimuths
used to measure relative bearings when aligned with the ships head & centerline
Speed Log
any device used to determine a vessels speed or distance traveled through the water
Doppler Speed Log
capable of giving a constant readout of speed and distance traveled to a high degree of accuracy

units can operate from bottom echoes in waters no deeper than 1500ft
What are 3 types of sounding devices?
hand lead line-
weight 7 to 10 lbs length 25 fathoms

deep sea lead-
weight 30-100 lbs length 100 fathoms or more

Electronic SOunding Devices-essential components are a transmitter, transducer, receiver, and display
The number of the chart is located________.
on the borders in a minimum of three places
Compass Rose
placed in convenient location on the chart to ease measurement of direction
outer ring is true
inner ring is magnetic
Where are boxes and notes printed on a chart?
where it wont block out other navigational information
Colors of the chart
yellowish/buff-land areas
blue-shallow or shoal water
white-deep water
green-submerged at some tidal stage
nautical purple-written informationlisted on the chart
Mercator projection
  • rhumb lines appear as straight lines
  • distance can be measured form latitude scale
  • great circles(except meridians and equator) appear as curves
  • meridian distorts at higher latitudes
  • used for marine navigation
Gonomic Projection
  • Great circles appear as straight lines
  • meridians appear as straight lines converging towards the nearest pole
  • parallels (except equator) appear curved
  • best used for planning great circle routes
One digit charts
EX Chart 1
symbol and abbreviation charts of the US and some other nations
Two & Three Digit charts
  • charts of very large ocean areas
  • divides world's waters into 9 ocean regions
  • first digit indicates region
Five Digit Charts
  • most often used by navigators
  • scale 1:2,000,000 and larger
  • first digit is ocean region
  • second digit sub-region
  • final 3 digits is specific location
Four Digit Charts
  • non-navigational
  • no scale
Sailing Charts
  • smallest scale charts used for planning, fixing position at sea, plotting and deadreckoning
Coastal Charts
intended for inshore coastal navigation, for entering or leaving bays and harborsof considerable width and for navigating large inland waterways
General Charts
intended for coastwise navigation outside of outlying reefs and shoalswhen the vessel is in sight of land or aids to navigation
Harbor Charts
intended for navigation and anchorage in harbors and small waterways
Small craft Charts
special charts for inland waters, inc. ICW or special editions of conventional charts

contains inforamtion of special interest to small boat operators
Who publishes charts of US territorial waters?
National Oceanographic Services
WHere can DOD customers order NOS charts?
through NGIA
National Geospacial and Intelligence Agency
Who publishes charts of foreign waters?
Who prepares charts of some inland rivers, chiefly the Mississippi, Ohio and Tennessee, and their tributaries?
Army Corps of Engineers

Purchased from District Engineer Offices
Where can NGIA products now be ordered through?
the Defense Supply Center Richmond (DSCR)
Notice to Mariners
Published weekly by NGIA

corrections and revisions of nautical charts and publications
Summary of Corrections
publidhed semiannually in 6 volumes by NGIA

latest edition of all nautical charts and publications
Local Notice to Mariners
Published weekly by local Coast Guard district

information of local interest only
Where is the standard compass located?
ships centerline on the weather deck near the bridge where least likely to be influenced by magnetic influences
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