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    6 Projection, Distances

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    Daniel England
    This document provides information on navigation concepts including position, direction, and distance. It discusses several methods of determining position such as latitude and longitude, loran systems, and position symbols on a chart. It also covers different ways of measuring and stating direction, including true, magnetic, and relative bearings, as well as converting between relative and true bearings. Finally, it addresses measuring distances on nautical charts using the latitude scale.

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    6 Projection, Distances

    Uploaded by

    Daniel England
    87 views35 pages
    This document provides information on navigation concepts including position, direction, and distance. It discusses several methods of determining position such as latitude and longitude, loran systems, and position symbols on a chart. It also covers different ways of measuring and stating direction, including true, magnetic, and relative bearings, as well as converting between relative and true bearings. Finally, it addresses measuring distances on nautical charts using the latitude scale.

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    This document provides information on navigation concepts including position, direction, and distance. It discusses several methods of determining position such as latitude and longitude, loran systems, and position symbols on a chart. It also covers different ways of measuring and stating direction, including true, magnetic, and relative bearings, as well as converting between relative and true bearings. Finally, it addresses measuring distances on nautical charts using the latitude scale.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    87 views35 pages

    6 Projection, Distances

    Uploaded by

    Daniel England
    This document provides information on navigation concepts including position, direction, and distance. It discusses several methods of determining position such as latitude and longitude, loran systems, and position symbols on a chart. It also covers different ways of measuring and stating direction, including true, magnetic, and relative bearings, as well as converting between relative and true bearings. Finally, it addresses measuring distances on nautical charts using the latitude scale.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    of 35

    Navigation

    NAU 102
    Lesson 6
    Lesson 6
    Position, Distance & Direction
    •Where am I?

    •How far is it?

    •Which way?
    Position

    Shown relative to fixed object.


    E.g. 1 nm north of
    Chesapeake light
    Position

    Shown by Lat/Long.

    (e.g. 36° 50.6’N


    075° 31.2’W)
    Position

    Plotting Lat/Long.
    Position
    Position
    Position
    Loran

    Long Range Navigation

    Hyperbolic system
    Based on time differences in received
    signals from Master and Secondary
    stations.
    Results in hyperbolic lines of position
    (LOP’s)
    Loran
    Components

    Master transmitting station

    Two or more Secondary stations

    Shipboard antenna and receiver

    Loran charts
    Loran Chains
    Loran

    Time Differences are displayed on a


    shipboard receiver.
    Position Symbols

    Visual fix – circle

    Electronic fix – Triangle

    R-fix Running fix – circle labeled “R-fix”

    Estimated position – square

    DR position – half circle


    Direction

    Different ways to measure/state direction.


    True direction – angle from true north (°T)

    Magnetic direction – angle from magnetic


    north (°M)

    Relative direction – angle from ship’s


    heading (°R)
    Direction

    Direction is stated in degrees or points.

    e.g. 045°T vs. North East

    e.g. 315°R vs. 2 points to port


    Direction
    Degrees
    Counted clockwise
    from the reference
    line.
    Stated in 3 digits
    N = 000°
    E = 090°
    S = 180°
    W = 270°
    Direction

    Points

    32 points in a
    circle

    11.25° = 1 point
    Direction
    Boxing the
    Compass
    Cardinal Points

    N = 0 pts = 000°
    E = 8 pts = 090°
    S = 16 pts = 180°
    W = 24 pts = 270°
    Direction

    Intercardinal Points
    Midway between
    cardinal points
    NE = 4 pts = 045°
    SE = 12 pts = 135°
    SW = 20 pts = 225°
    NW = 28 pts = 315°
    Direction

    Halfway between cardinal & intercardinal


    Stated cardinal then intercardinal

    NNE = 2 pts = 022.5° NNW = 30 pts = 347.5°


    ENE = 6 pts = 067.5° WNW = 26 pts =
    292.5°
    WSW = 22 pts = 247.5°
    ESE = 10 pts = 112.5°
    SSE = 14 pts = 157.5° SSW = 18 pts = 202.5°
    Direction
    Remaining points
    Nearest cardinal or
    intercardinal point by the
    next cardinal point
    N by E = 1 pt = 011.25°
    NE by N = 3 pts = 033.75°
    NE by E = 5 pts = 056.25°
    E by N = 7 pts = 078.75°
    Etc., etc.
    Direction

    Relative directions can be stated by


    degrees or points.

    e.g. 045° R or 4 points to stbd

    e.g. 315° R or 4 points to port


    Direction

    Bearing

    Direction of one object to another


    Stated True, Magnetic or Relative
    Can be in Degrees, Points or Words

    e.g. stbd beam, fine on port bow, stbd


    quarter, 2 points abaft the beam, etc.
    Direction
    Direction

    Bearing
    “To” vs. “From”

    A to B = 060°T

    A from B =
    240°T
    Direction

    You can convert between relative


    and true bearings.
    Relative Bearing + Ship’s Heading
    = True Bearing
    Direction

    R+S=T

    R=T–S
    And
    S=T-R
    Direction
    Example
    You are on course 170° T and you
    sight a vessel abeam to starboard.
    What is the true bearing of the vessel?
    R+S=T
    90° + 170° = 260° T
    Direction
    Example
    You are on course 250° T and on radar
    you detect a vessel at 125° T. At what
    is the relative bearing to the vessel?
    Direction
    You are on course 250° T and on radar you detect a
    vessel at 125° T. At what is the relative bearing to the
    vessel?
    R=T-S
    R = 125° - 250° = -125° R
    -125° R ???
    If < 0, add 360°
    360° - 125° R = 235° R
    Distance

    Measured using latitude scale on a


    Mercator projection chart.
    Use the scale at the mid-latitude of
    what you are measuring.
    Distance
    Introduction to Navigation

    Questions?

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