Carpe Diem Sailingvideo
Ep 37: Navigation: Basic Plotting Part 1
2 June 2021 · 23 min · 228K views
What this video covers
Coastal navigation requires a set of standard tools: parallel rules or a protractor, dividers, a 2mm 2B pencil, an eraser, a timepiece, and a navigator's notebook. To determine a position, a navigator takes bearings to known landmarks to create lines of position (LOPs). The intersection of two or more LOPs provides a fix, with the most accurate results occurring when LOPs intersect at 90-degree angles. When three LOPs form a small triangle, known as a "cocked hat," the navigator assumes a position within that area, prioritizing the side closest to any navigational hazards.
Dead Reckoning (DR) predicts a future position based on a known course and speed. Navigators plot a DR position by measuring the distance traveled along the course line using the chart's latitude scale. Comparing a manual LOP fix to a GPS fix (G-fix) helps verify accuracy and builds confidence in manual plotting skills.20:34 When taking multiple bearings while moving, prioritize landmarks closest to the vessel's centerline first, as these change the least. Practice and consistent labeling conventions are essential for maintaining a clean, readable chart.5:26
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