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weephee · 25-02-2015, 06:06

Is due west the same as true west or is it magnetic west. Thanks

**Ex-Calif** · 25-02-2015, 06:16

I've always considered it referenced to magnetic.

In daily use in the real world people use compasses not charts.

But if someone says something is "due west" and you are not sure it probably doesn't hurt to ask...

**a64pilot** · 25-02-2015, 06:34

I take due west to mean 270 deg., nothing more. Headings I thought unless otherwise specified were always magnetic?

**boatman61** · 25-02-2015, 06:38

To me its more of a general expression used for a temporary heading.. in the general direction of the setting sun.. to be firmed up when a situation has been resolved..
Your on watch and something goes up foreward.. you call an off watch crew to take the helm and as you head to the fore he asks course to steer.. to which you reply in general terms the course best suited to your needs..
Due West.. Due South.. whatever.. just a general direction to head..

captain58sailin · 25-02-2015, 06:41

The difference between true west and magnetic west is the variation. As previously stated by Ex-Calif, I would get clarification before plotting your course.

sparrowhawk1 · 25-02-2015, 06:51

This took hours of research: ) due west = the cardinal compass point that is 270° source: dictionary. Edit:
Totally did not mean this to sound as obnoxious as it does

weephee · 25-02-2015, 07:13

OK Sparrowhawk1, if I was told to plot a course due west on my chart, I would plot a line True West not magnetic west. I would not have to consider variance when plotting because plotted lines on a chart are all True degrees not magnetic. If I was told to plot a course magnetic west then I would have to calculate the variance and from that calculate the True course to plot. Is this correct

captain58sailin · 25-02-2015, 07:24

Yes, you also have to correct for deviation.

**boatman61** · 25-02-2015, 07:32

Quote:

Originally Posted by boatman61

To me its more of a general expression used for a temporary heading.. in the general direction of the setting sun.. to be firmed up when a situation has been resolved..
Your on watch and something goes up foreward.. you call an off watch crew to take the helm and as you head to the fore he asks course to steer.. to which you reply in general terms the course best suited to your needs..
Due West.. Due South.. whatever.. just a general direction to head..

However... when one takes into account the helmsman use's a Magnetic compass..
I'd say its definitly Magnetic on a boat..

sparrowhawk1 · 25-02-2015, 08:24

Quote:

Originally Posted by captain58sailin

Yes, you also have to correct for deviation.

And I also like the advice to confirm from the person that said due west exactly what they mean. Just because you know the technically correct answer doesn't mean the other person does. Edit you would correct for deviation for your vessel not sure if that applies to your question though

sparrowhawk1 · 25-02-2015, 09:26

As a side note when I'm using charts I like to plot my courses as compass. But sadly or sorcery I almost extensively use chartplotters these days

**a64pilot** · 25-02-2015, 10:04

I'm with Boatman, every time I have ever given a steer that is a Cardinal heading, it's just saying head thattaway and is meant to give me time to concentrate on whatever else needs my attention, after that I'll get us on course if need be.
I was taught that there are three headings, true, magnetic and compass FWIW

Stu Jackson · 25-02-2015, 10:07

This gets into that dangerous area, like anchors & religion, as to what is actually plotted on a chart.

The argument usually goes: It doesn't matter, 'cuz the chart has a compass rose which actually shows both, so LABEL the darned lines you draw and call it a day.

The other side points out that if you are traveling a long distance and plotting on large scale charts, the variation changes so all course lines should be drawn as true.

IMHO, both points make sense, so it's not either/or. Just label them properly.

In answer to the OP, my question would be: "Just how long would you expect someone to continue heading "due west?" If it's for an hour in open water, doesn't really matter. If you're talking a full watch stand near a coastline, it sure does.

I like the dictionary definition, though, very thoughtful research and helpful homework.

denverd0n · 25-02-2015, 10:16

"Due West" is an American country music group--Wikipedia says so. It is also the name of a town in South Carolina. "Due South" is the name of a TV show, and a British magazine.

If you are talking about navigation, then there is no one, universally-accepted meaning for these terms (due west, due east, due north, due south). Its meaning is entirely dependent on the context, and the intention of the person using the term. So if you want to be sure, ask.