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Lesson 5: Navigation Instruments

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Title: Marine Navigation and Naval Operations I Author: LT C.T. MONROE, USN Last modified by: Dave Created Date: 11/2/1998 5:06:22 AM Document presentation ... – PowerPoint PPT presentation

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Title: Lesson 5: Navigation Instruments


1
Lesson 5 Navigation Instruments
2
Lesson 5 Navigation Instruments
  • AGENDA
  • Measurement of Depth
  • Measurement of Direction
  • Measurement of Distance
  • Measurement of Speed
  • Applicable reading Hobbs pg. 110-128.

3
Measurement of Depth
  • Echo Sounder (fathometer)
  • Hand leadline

4
Lead Line
  • Manual method of determining depth
  • Also allows for a sampling of the bottom type

5
Measurement of Direction
  • Bearing the horizontal direction of one
    terrestrial point as measured from another,
    expressed as an angle from 0 to 360 degrees.
  • There are three references for bearings
  • Relative
  • Magnetic
  • True

6
000T / 270R
090T / 000R
270T / 180R
180T / 090R
7
Measurement of Direction
  • Visual Bearings can be measured in
  • - Degrees Relative ( 0R )
  • - Degrees Magnetic ( pstgc OR 0M )
  • - Degrees True ( 0T)
  • The navigator must convert any of these types
    of bearings to True before they can be plotted on
    the chart.

8
Bearing Circle/Alidade
  • Azimuth or Bearing Circle
  • Telescopic Alidade

9
Bearing Circle
  • Telescopic Alidade

10
Measurement of Distance
Radar - Distance is obtained by a radio wave
that is transmitted into the air and returns as
an echo. The time interval between
transmission and return can be converted
into a physical range.
Used for distance (range) only!! Not normally
used for bearings
11
Measurement of Distance
STADIMETER
Used to determine precise ranges between ships in
formation
12
Making an Observation with the Stadimeter
  • Distance is determined by
  • distance height of object / tan (angle)

13
Plotting Instruments
  • Parallel Ruler

14
Plotting Instruments
  • Parallel Plotter

15
Plotting Instruments
  • Parallel Motion Protractor

16
Plotting Instruments
  • Compass
  • Dividers

17
Plotting Instruments
  • Nautical Slide Rule

18
Operation of Nautical slide Rule
  • Given two of the following, find the third
  • Speed
  • Distance
  • Time

19
Measurement of Speed
  • Speed over Ground (SOG) true speed
  • Speed through the water
  • SPEED OVER GROUND
  • Direct output of many electronic navigation
    systems (GPS, Loran)
  • SPEED THROUGH WATER
  • Impeller Log
  • Pitotmeter Log
  • Doppler Speed Log
  • Shaft RPM

20
Measurement of Speed
  • Impeller Log

21
Measurement of Speed
  • Pitometer (Pit) Log

22
Measurement of Speed
  • Doppler Speed Log

23
3 Minute Rule
  • The Distance in yards that a ship travels in 3
    minutes (D) is equal to the Ships Speed (Spd) in
    knots multiplied by 100.
  • D Spd x 100

24
6 Minute Rule
  • The Distance in nautical miles that a ship
    travels in 6 minutes (D) is equal to the Ships
    Speed (Spd) in knots divided by 10.

25
REVIEW
  • What does a fathometer measure?
  • What does DSpeed x 100 tell you?

26
QUESTIONS??
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