THREE POINT FIX

1. THREE POINT FIX K STEPNITZ 5-1-2008

2. Find three fixed objects that are shown on your chart. A C B

3. Bearings are taken from these three fixed points. A C 300° psc 70° psc 200° psc B

4. To draw these bearings on a chart, you must convert from psc to TRUE.

5. To draw these bearings on a chart, you must convert from psc to TRUE. This is done using TVMDC. Remember that the deviation depends on the boats HEADING.

6. To draw these bearings on a chart, you must convert from psc to TRUE. This is done using TVMDC. Remember that the deviation depends on the boats HEADING. The TRUE bearing does not change with the heading of the boat. Due to the deviation the psc bearing will change with the heading.

7. TRUE Bearings do not change as the HEADING changes. A C 300° T 70° T 200° T B

8. psc bearings DO change as the HEADING changes. A C 300° psc 70° psc 200° psc B

9. psc bearings DO change as the HEADING changes. A C 303° psc 73° psc 203° psc B

10. psc bearings DO change as the HEADING changes. A C 301° psc 71° psc 201° psc B

11. psc bearings DO change as the HEADING changes. A C 299° psc 69° psc 199° psc B

12. psc bearings DO change as the HEADING changes. A C 296° psc 66° psc 196° psc B

13. psc bearings DO change as the HEADING changes. A C 298° psc 68° psc 198° psc B

14. psc bearings DO change as the HEADING changes. A C 300° psc 70° psc 200° psc B

15. psc bearings DO change as the HEADING changes. A C 302° psc 72° psc 202° psc B

16. psc bearings DO change as the HEADING changes. A C 305° psc 75° psc 205° psc B

17. psc bearings DO change as the HEADING changes. A C 301° psc 71° psc 201° psc B

18. psc bearings DO change as the HEADING changes. A C 298° psc 68° psc 198° psc B

19. psc bearings DO change as the HEADING changes. A C 295° psc 65° psc 195° psc B

20. psc bearings DO change as the HEADING changes. A C 300° psc 70° psc 200° psc B

21. The TVMDC will look like this. We will use a HEADING of 045°and we are in a region where theVARIATION is 15W.

22. The TVMDC will look like this. We will use a HEADING of 045°and we are in a region where theVARIATION is 15W.

23. The TVMDC will look like this. Using a HEADING of 045°and the deviation table we find the deviation to be 3E

24. The TVMDC will look like this. Using a HEADING of 045°and the deviation table we find the deviation to be 3E

25. The TVMDC will look like this. IMPORTANT: Notice that we have not done anything with the BEARINGS yet.

26. The TVMDC will look like this. Next we insert our compass BEARINGS(psc).

27. The TVMDC will look like this. Next we insert our compass BEARINGS(psc).

28. The TVMDC will look like this. Now we correct these values to get FROM Compass to TRUE.

29. The TVMDC will look like this. Now we correct these values to get FROM Compass to TRUE.

30. The TVMDC will look like this. These are the lines we can draw on the chart.

31. Once the TRUE Bearings have been determined they are plotted on the chart. A C 300° T 70° T 200° T B

32. Notice that the LOP’s may not cross at one point. A C 300° T 70° T 200° T B

33. In this case your location is at the center of the triangle formed. A C 300° T 70° T 200° T B

34. Your Latitude and Longitude are now found by careful use of the parallel rules or dividers and the scales along the edges of the chart.