Fix position distances and compass bearings distances and compass bearings 1
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- Опубликовано: 10 сен 2024
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You can obtain a fix by combining two or more distances or distances and compass bearings.
This is how you plot a fix position combining two or more distances:
Let's assume you sail near the coast.
The radar is in good working condition and in operation.
Taking into account your last position, and after comparing the nautical chart's coast line with that on the radar screen, you spot two points on the screen, A and B, from where you can take distances.
The equivalent ones on the nautical chart are points A and B.
Using the radar's range marker you measure a distance of 5.2 nautical miles from point A, and 2.8 nautical miles from point B. You note the time - let's assume it is 0930 hours.
Then return to the nautical chart, and using the dividers, span a distance of 5.2 nautical miles on the latitude scale which is closest to the present position and which runs along the sides of the chart. Apply this span, placing one leg of the dividers at point A, and draw a semicircle near the course line.
Now span a distance of 2.8 nautical miles and apply this span, placing one leg of the dividers at point B, and draw a second semicircle intersecting the first semicircle and near the course line.
The point where the two semicircles intersect is the fix position at 0930 hours.
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What if there are two intersections? Our teacher gave us an activity and we are confused because there's multiple intersections. He said the first one to intersect but how do you if its the first one cuz based on how you draw, either of them can be the first.
Then you need a third point to take a distance. You can get away with only two like in that example because the second intersection is in land and the boat is obviously not there.