Well it's a new one on me.

[Peppermint]

Well it\'s a new one on me.

I'm helping a mate through an intensive Coastal Skipper theory course. Thats helping like cutting the rope on a fellow climber. But anyway I seem to be more help than his regular skipper, a man of huge sailing experience and the owner of a tidy 40ft Ben, who has instructed him that westerly variation only applies when going west and that, yes you've guessed, going east you apply your variation to the east.

Anybody else doing it this way?

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[Superstrath]

Re: Well it\'s a new one on me.

These have always stuck with me:
Cadbury's Dairy Milk Very Tasty or
Cadets Don't Meet Virgins Twice for Compass-Deviation-Magnetic-Variation-True

and True Virgins Make Dull Companions for True-Variation-Magnetic-Deviation-Compass

For remembering which way to apply V&D; Error West, Compass Best, Error East, Compass Least.

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[oldsaltoz]

Re: Well it\'s a new one on me.

G'day Tom,

When did this change?????????

Teach your friend the old C-A-D-E-T.

C = Compass reading, magnetic
A = Add or subtract
D = Deviation (and this applied over all 360*.
E = Error as per compass card, plus or minus.
T = True. as opposed to magnetic.

Works for me, perhaps the skipper can explain why we say "compass East error least (or minus), compass west error best (or add)".

Then explain why it does not apply to all headings.

Meantime Avagoodweekend..........



<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.

 

[tcm]

Re: What, you mean, doing it completely wrong?

Um, well, i don't, and i am sure you don't either!

There's no "trick" to variation and the parroting CADET etc alone can merely add to confusion. Your mate needs to understand the background and it's not that hard. I used this as an explanation to another person a while back:

Lets say you are looking at a chart of UK. True North is at north pole. Let's say that Magnetic north is somewhere in Greeenlandish. So on this chart, that means the variation is therefore (say) 6 degrees West. In other words, magnetic north seems from here to be 6degrees to the west of true north.

This means that if a compass which said yup, that's North! 000M or 360M - it would actualy be pointing 6degrees west of true north : at 354T.

Perhaps think of this like a clock. With westerly variation the compass starts counting "too early", or "too late" for an easterly variation. The compass says 90 - but (if a westerly variation) it "started counting" too early: six degrees too early. So now that it says 90, it is reading too high - it's really only 84T.

Likewise, if the compass says 180, and the variation is 3degrees *east*, then the compass starts counting too late. It's really 183True. Add these easterly deviations, subtract the westerlies.

parrotywise, compass add deviation East = True , CADET

Deviation works the same way, but varies with heading - possibly the confusion with your mates skipper (or your mate).

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[claymore]

Well - you surprise me!

Greenland? I thought you kept your boat in the med?

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Claymore
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[alant]

Re: Well it\'s a new one on me.

On Tele other night, showed Canadian bloke who is the one who checks location of North Pole each year. Hence allowing us to know variation.
Apparently rate its moving has doubled, now about 40 metres/annum.

Your mates instructor, sounds like the guy who thought leading marks where used only when entering, but not required when leaving a harbour/river/anchorage.

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[tcm]

Re: Well - you surprise me!

yes it is in greenland, BUT allowing for the deviation, it's actually in the med. of course.

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[peterb]

Re: Well it\'s a new one on me.

Cadbury's Dairy Milk Very Tasty.

True Virgins Make Dull Companions.

Well that's dealt with Gluttony and Lust, only five more deadly sins to go

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[LadyInBed]

Re: What, you mean, doing it completely wrong?

My pretty Polly for variation from way back when the Army taught me to read maps was
Grid to Mag add
Mag to Grid get rid
(Mag being compass and Grid being OS grid on the map)
Not sure what I shall do when the variation eventually swings East!
The other never forgotten one to remember which way round to report / interpret a grid reference was
‘Along the landing and up the stairs’


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[tome]

Re: What, you mean, doing it completely wrong?

I remember similiar except 'Walk before you Climb' for grid.

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[peterb]

Re: What, you mean, doing it completely wrong?

And I remember "You go indoors before you climb the stairs."

Any more?

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[graham]

Re: Now your really confusing people!!

I f you apply the method of giving military grid references with lat and long you will totally bo!!oc$ your position.

After having map reading banged into my head for years I still get it wrong occasionally when looking at charts.

OBVIOUSLY when doing lat and long you go up the side first .So maybe Up the fire escape then across the kitchen would do.

I still use Grid to Mag add though .Anyone know when the UK will be on zero variation?

The 1000 mil compass would be confusing afloat,imagine telling your mate to steer 750 .

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