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post #11 of 122 Old 02-27-2010
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Ditto... 3 degrees @ 60 nm/degree = 180 nm, + 13' @ 1 nm/' = 193 nm.

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post #12 of 122 Old 02-27-2010 Thread Starter
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The true heading is 010° but the magnetic heading from the compass rose on the chart reads 012°; What is the variation?

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post #13 of 122 Old 02-27-2010 Thread Starter
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One other:
the scale of a chart is 1:80,000. What distance at sea does a distance of 3.5 inches on the chart represent? What distance on the chart represents an actual distance of 14.3 NM?






Remember that a NM is 6076.11549 ft thought we use 6000 ft for practical purposes.

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Last edited by Boasun; 02-27-2010 at 12:47 PM.
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post #14 of 122 Old 02-27-2010
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Quote:
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The true heading is 010° but the magnetic heading from the compass rose on the chart reads 012°; What is the variation?
2° West

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post #15 of 122 Old 02-27-2010
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You do not need the chart.

This an example that I use to teach set and drift, CMG, SMG, CTS, Speed.

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On November 18, 2003 we plan on leaving Thieves Bay Marina, Mouat Point Light (Lat 48°46.5’N Long 123°18.75’W) for Isabella Island (Lat 48°43.75’N Long 123°25.75’W). We will use the current information for Swanson Channel. The chart shows the flood direction to be 360. Using our current prediction tables, we determine that that the drift is 1 knot. Our boat speed is 5 knots. Our course to make good is 242T. We need to gauge our speed made good and our course to steer.

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post #16 of 122 Old 02-27-2010
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Answer to set/drift prob.

CTS = 252 T
VMG = 5.4 kt
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post #17 of 122 Old 02-27-2010
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Quote:
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CTS = 252 T
VMG = 5.4 kt

Not quite

The solution is here:

http://www3.telus.net/jackdale/navlessons/detercts.pps Works best in IE.

For Firefox - Determining Course to Steer

Jack

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post #18 of 122 Old 02-27-2010
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Riddle me this

If the wind is reported as 360T, it's coming from the North. If the current (set) is reported as 360T, it's going to the North. Who decided this, and was it done just to torture me?
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post #19 of 122 Old 02-27-2010
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The set is 360. You are being pushed north. The wind is not a factor.

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post #20 of 122 Old 02-27-2010
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Sorry -- I wasn't saying the wind was a factor. I was just asking why, when set is reported, it's the direction I'm being pushed. But when wind direction is being reported, it's the other way around. So if the wind is 360T, it's *from* the north, but when current is 360T, it's *to* the north.
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