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Old 15-07-2010, 20:09
jezzc100's Avatar
jezzc100 jezzc100 is offline
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Default North Atlantic Plotting Chart (NAP)

Just wondering whether there is a trick for ascertaining distances using this particular chart - I don't see a scale anywhere.

Is it simply a case of measuring given distance with dividers and then comparing against lines of latitude (longitude??) to find out out degrees of separation and then multiply by 60 to get distance in NM??

Is there a quicker way??

Thanks in advance.
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Old 15-07-2010, 20:33
Hayder Hayder is offline
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Default Re: North Atlantic Plotting Chart (NAP)

I had the same problem. Just could not find the scale anywhere on the map.

The scale is: 1 Inch = 120NM


It's located on the front of the map, top left hand corner underneath <---- MAP
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Old 15-07-2010, 21:31
doolittle doolittle is offline
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Default Re: North Atlantic Plotting Chart (NAP)

Whatever you do, don't do what Hayder has just said (no offense but that's only accurate at a particular part of the map and the CAA won't give you that part!), do exactly as you thought Jezz measuring vertically down the closest Meridian with each degree being 60NM. (Latitudes suffer from Departure unless your on the equator so don't measure along one for the scale). It does take a while to measure accurately but I had a question on this in my recent Gen Nav exam so it paid off. (Still, I probably got it wrong though) )
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Old 15-07-2010, 23:26
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Tony Pike Tony Pike is offline
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Default Re: North Atlantic Plotting Chart (NAP)

As already stated, use dividers between points A and B - I suggest using dividers with a screw thread adjuster to prevent slippage. Then, place the dividers along the Meridian nearest to the line being measured (this reduces the error of scale expansion), with one point on a 'round number' line of latitude, e.g. 55 N. Count the number of Minutes (1 degree = 60 minutes) from the starting point and this will equal the distance in NM.

Again, as stated, DO NOT use lines of latitude other than the equator.

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  #5  
Old 16-07-2010, 17:44
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jezzc100 jezzc100 is offline
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Thumbs up Re: North Atlantic Plotting Chart (NAP)

Many thanks for helpful replies.
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