NS101_05 - Fundamentals of Navigation (FALL-15)

8/9/2019 NS101_05 - Fundamentals of Navigation (FALL-15)

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NS101 Fundamentals of Navigation


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Know how to read a latitude and longitude position and determine its location on a

chart

Comprehend the theory and practice of navigation at sea

Know the four ways in which Direction is expressed

Know the capabilities and limitations of various instruments used in piloting

Know the composition of the Piloting and Radar Navigation Teams

Required Reading Dutton!s Nautical Navigation" #$thedition" pgs% #&'##" #()**" ++)

,&" (,'-+ N./D0R1 2C01N./.3R40R3N5T 6 C01N./57R40R3N5T

+$+&%,C8

Enabling Objectives


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Coordinate Systems


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Coordinate Systems

Degrees of 9ongitude are always expressed in + digit format%


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Position

!"#$0%00& N

' 0"(#1"%)$& *

9atitude

9ongitude


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.ttemptsto portray the surface of the earth on a flat surface%

There are hundreds of pro:ection types" but only a few are common to nautical

navigation based on desirable properties

-True shape of physical features such as bodies of land or water-9and masses and6or bodies of water are represented in correct relative proportions

-Correct angular relationships '; our nautical chart is a 1ercator Pro:ection%

Projections


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+ercator C,art Projection

3magine wrapping a sheet of paper around the earth" with a light bulb in the

center to pro:ect the image of the earth!s surface% 7nwrap the paper and?%

Note

- scale increases rapidly

toward poles%

- =reat Circles appear as

curved lines%

- Rhumb 9ines are

straight lines%

.dvantages' @ase of measurement2distance" direction A position8-9atitude6longitude drawn as straight linesand can be easily plotted

Disadvantages' Distortion of features at extreme latitudes


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-reat Circles vs .,umb /ines

- The shortest distance between any two points on the surface of the @arth is

always along the =reat Circlebetween themB however" a ship!s course on a

great circle route would be sub:ect to continuous alterations which is not

practical%

- 5inceconstant course changes are not practical" it is customary to follow aRhumb 9ine on a 1ercator Chart rather than a great circle%


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atum

- . geodetic Datum is a reference point in

which position measurements are made to

create a networ


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ime 2ones

- =reenwich 1ean Time 2=1T8 1ean solar time measured with reference to the

prime meridian% 3t is often referred to as H797 time

- Time within each Ione is determined in relation to the central meridian of the

Ione

22.5 W 15 W 7.5W 0 7.5E

15E 22.5E

Zone Zone Zone

+ 1 N 0 Z -1 A

Zone descriptor2one escri3tion 4The ad:ustment that must be applied to the

time of a particular Ione to obtain =reenwich mean time

2=1T8


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ime 2ones

2one ime (local time) 4 5olar time rec


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C,art One

Jac< cover of Chart 0ne lists all chapters and their contents%

3ncludes =eneral" Topography" Eydrography" .ids and 5ervices" and 3ndexes

Jest reference for loo


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N56O.+

@stablishes common baseline for 5urface 5hip Navigation

.vailable online

5tandard Navigation Jill

Responsibilities for maintenance of shipboard Nav Jill

Duties6Responsibilities and organiIation of Nav TeamProcedures for restricted waters navigation" open ocean navigation

=uidelines for ships to craft their own N./D0R1 ) i%e% minimum requirements in the Navigation Jill%

Jasic 5


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@xpressed in four ways

#% True'; Referenced to TR7@ N0RTE" is the angular distance measured from &

to +& degrees between two points on the earth!s surface%

*% Relative'; Referenced from the 5E3P!5 J0

+% 1agnetic'; Referenced to 1.=N@T3C N0RTE" which is based on the

magnetic influences which vary as you move around the earth% The differencebetween true and magnetic north in any given location is


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Piloting 7nstruments


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.Iimuth Circle Telescopic .lidade

#% 9oo< through the front peep vane

*% 9ine up forward wire with center of slot and ob:ect

+% 9oo< into prism to obtain bearing 2true or relative8

,% Record bearing for plotting%

+easuring irection


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+easuring istance

Radar' Distance is obtained by a radio wave that is transmitted into the air and returns

as an echo% Time interval between transmission and return is converted into a range%

5tadimeter' 7ses two logarithmic scales to determine distance to ob:ects of


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+easuring S3eed

5peed over =round) GTrueL speed relative to the @arth%

@quipment =P5" Doppler 5peed 9og

5peed through the water) GRelativeL speed between the water and the ship" not

accounting for the effect of current or seas%@quipment 3mpeller 9og" Pit 9og" 5haft RP1


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+easuring S3eed

3mpeller 9og) 1easures speed through the water by translating the rotation of a small

propeller or paddle wheel below the water line into a measurement of fluid speed%

Pit 9og) +'foot long tube extended beneath the


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+easuring e3t,

4athometer) 7ses a transducer that transmits a sonar pulse vertically in the water%

The fathometer computes the depth by measuring the time interval from transmission of

the sound until the return of the echo%


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8ridge9Piloting eam

Primary navigation plot using visual navigation aids 2Navaids8


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C7C9.adar Navigation eam

5econdary navigation plot using radar navigation aids 2Navaids8


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:uestions ;

NS101_05 - Fundamentals of Navigation (FALL-15)

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