
Lesson 5 - Position Fixing
Overview
Position fixing determines where you are at sea. This is essential because steering inaccuracies, wind, and tidal streams can push you off course.
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​Single Fix
One of the simplest techniques involves spotting a clear landmark, like a lighthouse or buoy, and matching it to your chart. Ideal for coastal navigation.
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Position Line
A position line shows where your boat must lie based on an observation, such as a compass bearing, radar range, or visual transit. Two intersecting lines give an accurate fix.​​​
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​​​​GPS
GPS uses satellites to pinpoint your location with remarkable accuracy. Systems like dGPS and WAAS correct errors for even greater reliability.
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Quick Plotting Techniques
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Range and bearing allow quick fixes.
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Use the "fastest last rule" to prioritize bearings for the most accurate results.​
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​Cross-Track Error (XTE) & Chart Plotters
XTE shows how far off your planned route you’ve drifted. Chart plotters provide real-time updates, making navigation faster and easier.​
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Traditional Navigation Methods
Techniques like the three-point fix, transits, and depth contours are reliable backups and great for cross-checking GPS data​​

Transits
Techniques like the three-point fix, transits, and depth contours are reliable backups and great for cross-checking GPS data
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Depth Contours
If you’re in shallow water, depth contours can act as position lines when matched to your chart.
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