Lesson06 Lines of Position and Fixes

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Please let me download your powerpoint presentation on the lines and position fixes. Thank you.

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Lesson 6: Lines of Position and Fixes: 

Lesson 6: Lines of Position and Fixes

Slide2: 

AGENDA: Visual and Radar Lines of Position -LOP’s Plotting Visual and Electronic Fixes Resolving Fix Ambiguity Applicable reading: Hobbs pp. 129-134, 142-147, 174-176. Lesson 6: Lines of Position (LOP) & Fixes

Learning Objectives: 

Learning Objectives 1. The student will comprehend how sources of visual ranges, visual bearings, and distance LOPs are selected, acquired and plotted. 2. The student will comprehend which combinations of LOPs used in determining a fix are most reliable and desirable. 3. The student will apply correct procedures to become proficient in plotting and labeling fixes.

Learning Objectives: 

Learning Objectives 4. The student will comprehend the use of radar in piloting. 5. The student will comprehend the use of danger bearings and apply correct procedures to plot and label such bearings. 6. The student will comprehend the difference between a fix and an estimated position (EP) and know the proper labeling procedure for EPs.

Lines of Position (LOP’s) : 

Lines of Position (LOP’s) LOP - A single observation that does not establish a fix but does mean that ship’s position somewhere along that line. Label - After the LOP is drawn from a Navaid, a four digit time must be written above and parallel to the Line of Position.

Slide6: 

Sources of Lines of Position (LOP’s) A visual LOP can be taken, or “shot”, using fixed navigational aids such as tanks, water towers, church steeples, spires, radio and TV towers, daymarkers, fixed navigation lights, flagpoles, or tangents to points of land.

Slide7: 

1000 Light Visual LOP 9 9 9 9 9 9 9 9 9 9 9 5 5 5 5 11 11 11 11 11 11 11 11 6 pa FL 6s 58ft 9M Tank Long Point 20 20 20 20 20 20 21 20 20 20 21 21 21 21 21 23 23 23 23 23 15 15 15 15 17 17 17 17 19 19 19 19

Slide8: 

Light Radar Range LOP 9 9 9 9 9 9 9 9 9 9 9 5 5 5 5 11 11 11 11 11 11 11 11 6 pa FL 6s 58ft 9M Tank Long Point 20 20 20 20 20 20 21 20 20 20 21 21 21 21 21 21 23 23 23 23 23 23 15 15 15 15 17 17 17 17 19 19 19 19 1500

Slide9: 

0635 070

Slide10: 

Visual Ranges Visual Range - The most accurate type of LOP, when two known objects line up. Visual Ranges - Some ranges are man made: “intentional” and others are natural: “coincidental.”

Slide11: 

COINCIDENTAL RANGE

Slide12: 

INTENTIONAL RANGE

Measurement of LOP’s: 

Measurement of LOP’s Visual Bearings can be measured in: - Degrees Relative ( # # # 0R ) - Degrees per Gyro Compass ( # # # pgc ) - Degrees Magnetic ( # # # 0M ) - Degrees True ( # # # 0T) The navigator must convert any of these types of bearings to True before they can be plotted on the chart.

Plotting and Labeling a Fix : 

Plotting and Labeling a Fix Fix - The point where two or more LOP’s cross. This indicates the ship’s position on the chart. Label - Use the four digit time next to the fix, it should be parallel to the bottom of the chart. The times of the individual LOPs are not written on each LOP.

Slide15: 

Light Visual Fix 9 9 9 9 9 9 9 9 9 9 9 5 5 5 5 11 11 11 11 11 11 11 11 6 pa FL 6s 58ft 9M Tank Long Point 20 20 20 20 20 20 21 20 20 20 21 21 21 21 21 21 23 23 23 23 23 23 15 15 15 15 17 17 17 17 19 19 19 19 1000

Slide16: 

12 6 6 6 6 12 12 12 Tank Electronic Fix 1000

Slide17: 

Symbol Type Meaning Labeling Fixes Fix Fix DR EP Accurate Visual Fix Accurate Fix obtained by electronic means Dead reckon position, advanced from previous fix. Estimated position. Most probable position of ship.

Using the Centroid Concept: 

Using the Centroid Concept Problem - If a large triangle is formed by a 3 LOP fix, mark the center of the triangle as the fix. Danger - If the large triangle is near a hazard then choose the part of the triangle closest to the hazard.

Slide19: 

SPIRE TWR TANK 1036 1145 wk Visual Fix

Optimum Spread of LOP’s: 

Optimum Spread of LOP’s Best Fix - LOP’s must be widely spaced, two LOP’s at nearly the same angle will be less accurate. Formula - 3600 / number of LOP’s Example: There are three LOP’s then optimum separation is 1200.

Slide21: 

TWR TANK LT 60 60 0930 Visual Fix

Slide22: 

TWR SPIRE TANK 90 1036 1039 Visual Fix

Determining the Sequence of Shooting LOP’s: 

Determining the Sequence of Shooting LOP’s Bearings LOP’s - “Shoot” visual bearings that are on the beam first because they change the fastest. Shoot Bearings: “Beam to Bow” Range LOP’s - “Shoot” radar ranges on the bow/stern first because their range changes fastest. Shoot Ranges: “Bow to Beam”

Navigational Aid Selection: 

Navigational Aid Selection Choose Nav Aids based on: - Provides the best bearing spread. - Lighted so that Nav Aids can be used in low visibility and day or night. - Easily distinguishable by bearing takers. Example: Which radio tower?

Other Concepts: 

Other Concepts Track and SOA (Speed of Advance): Danger Bearings Estimated Position

Questions?: 

Questions?