Welcome to the United States Power Squadrons' Chart Smart Seminar

1. Welcometo the • United States Power Squadrons' • Chart Smart Seminar Piloting - Determining Position (Section 7)

2. Section 7: Piloting - Determining Position Dead Reckoning Class Plotting Exercises Class Agenda - cont'd

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4. Definitions • Dead Reckoning (DR) • Calculating a boat's position based on its course, speed, and time run from a previous position • Dead Reckoning (DR) Track • The intended course line of a vessel as plotted on a chart • DR Position • The presumed position of a vessel on a DR track

5. Rules for Plotting “DR” Tracks • Must start from a known position • Can only restart from known position • Use only true courses for labeling • Use only speed through the water • Calculate and plot DR position hourly • Plot DR position at time of every change • of course and speed

6. Labeling a DR Track and Position

7. Bearings • Magnetic Bearing • Bearing taken using the compass • True Bearing • Magnetic bearing corrected for • local variation – East or West • Can be plotted on a chart as a line • of position

8. 303° T _____ V _____ M _____ D _____ C _____ 3° W Add East Subtract West 306° 0 ° 306° Compass to True Bearing Deviation is assumed to be 0°for demonstration only

9. A Bow-On Bearing North True Bearing "To" TB = 040 ° Variation V = 15 W Magnetic Bearing MB = 055 ° Deviation * D = 0 W Compass Bearing "To" CB = 055 Compass Direction - 055 Determining a Line of Position - as a graphical aid, plot the reciprocal true bearing (040 + 180 = 220) from the navigation object * Note: deviation is assumed to be zero for demonstration only

10. A Bow-On Bearing North Compass Direction - 055 Determining a Line of Position - as a graphical aid, plot the reciprocal true bearing (032 + 180 = 212) from the navigation object * Note: deviation determined from example Deviation Table displayed in Class #1; interpolated to 055°

11. 1430 Fix By Two Bearings Note: 1430 fix time label is to be parallel to the bottom of the chart; 1430 DR time label is to be at an angle to the DR track.

12. Mark at303 Note: 1430 fix time label is to be parallel to the bottom of the chart; 1430 DR time label is to be at an angle to the DR track.

13. Mark at303 Note: 1430 fix time label is to be parallel to the bottom of the chart; 1430 DR time label is to be at an angle to the DR track.

14. Class Exercise #5 Use the Sample Plotting Sheet (Figure 23 in your text) to work through the problems starting on page 44 and continuing on page 45.

16. Class Exercise #6 - Chart Work Positioning by Compass Bearingson the Bowditch Bay Practice Chart

17. Bowditch Bay Chart Work Problem “6” You are enroute from RG "D" Gong to R "6" and take bow–on compass bearings at 1320 on: (1) Fl 8 sec 42ft Lt Ho on Duttons Is - 087 ° (2) Fl 8 sec 20ft Lt Ho on Channel Is - 267 ° (3) Fl Red 4 sec R "6" - 196 ° Correct the compass bearings to true bearings (assume deviation is zero) Plot and label your bearings & fix on the chart and determine latitude and longitude.

19. Compass to True Bearing Duttons Is Channel Is R "6" T = 072 ° T = 252 ° T = 181 ° V = 15 ° W V = 15 ° W V = 15 ° W M = 087 ° M = 267 ° M = 196 ° D = 0 ° D = 0 ° D = 0 ° C = 087 ° C = 267 ° C = 196 ° Add East Subtract West

20. 1320 072 1320 1320 252 1320 181 FIX

21. Position of Fix Latitude 41° 43.1 ' N Longitude 071° 19.7 ' W

22. End of Section 7 Piloting - Determining Position

23. Questions ? … Comments ? End of Seminar