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Old 11-03-2015, 00:09   #76
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Re: True or Compas

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Originally Posted by El Pinguino View Post
I just wrote that in longhand for the benefit of the OP and possibly others.

In fact what I would write is simply..

195*T
12*E
183*M

You know thats why there are empty bits on the chart with no soundings so you can write stuff.
I presume your chart already has 12E written on it like mine does so there is no need to write it again...

You must work for the department of redundancy department...
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Old 11-03-2015, 00:24   #77
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Re: True or Compas

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Originally Posted by Ex-Calif View Post
I presume your chart already has 12E written on it like mine does so there is no need to write it again...

You must work for the department of redundancy department...
Welll... no...it doesn't. The chart in question sez, within the rose... Varn. 8*05E.(1950) and on the other side of the rose it sez .. increasing abt 5' annually.

OK it was cancelled in about 1990 but the only diff between that and the present metric chart is 3 RDF beacons expunged and a solitary gas production platform added.

Also if you are using an offshore chart it will most likely simply have isogonal lines and nothing within the rose or roses.....
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Old 11-03-2015, 00:59   #78
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Re: True or Compas

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Originally Posted by El Pinguino View Post
Welll... no...it doesn't. The chart in question sez, within the rose... Varn. 8*05E.(1950) and on the other side of the rose it sez .. increasing abt 5' annually.

OK it was cancelled in about 1990 but the only diff between that and the present metric chart is 3 RDF beacons expunged and a solitary gas production platform added.

Also if you are using an offshore chart it will most likely simply have isogonal lines and nothing within the rose or roses.....
So your chart is out of date...

(Look - I don't care - because 99% of everyone has old charts. And not aimed at you but those guys throwing rocks at people about electric navigation, gps, sextants etc. is pretty hypocritical)

PS - No dredging or any bottom changes in 65 years? No waterfront development? Dock changes? Wow! Does Opie still fish in the crick? - LOL...
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Old 11-03-2015, 02:02   #79
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Re: True or Compas

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Originally Posted by Ex-Calif View Post
So your chart is out of date...

(Look - I don't care - because 99% of everyone has old charts. And not aimed at you but those guys throwing rocks at people about electric navigation, gps, sextants etc. is pretty hypocritical)

PS - No dredging or any bottom changes in 65 years? No waterfront development? Dock changes? Wow! Does Opie still fish in the crick? - LOL...
Nope... no changes... the chart I am looking at is the old 'imperial' chart of Bass Strait, western sheet... the 'new' metric chart presents exactly the same information, lines of soundings etc as this one in a fancy new colour... with a notation along the lines of 'gps possies may not quite match up with reality this chart'.

Do you recall Ping's world famous in New Zealand 'Rule of 1 inch'.... ? This chart is good up to maybe half an inch.... and it comes with those lovely old drawings of the coast.
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Old 11-03-2015, 02:06   #80
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Re: True or Compas

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Av charts are only good for 90 days but if one flies a lot even in 30 days the chart can get very polluted with chicken scratch.
I've never found that with charts used recreationaly but in the day job.... going up and down the same line night after night would wear a chart out pretty quick. We used to stick Scotch Magic Tape along the course line... that would extend the life a bit.
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Old 11-03-2015, 02:34   #81
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Re: True or Compas

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Originally Posted by goboatingnow View Post
also called Portland plotters

very handy on small chart tables where the chart is often folded
I almost exclusively use the Douglas Protractor. Perfect for small areas, contains straight edge, parallel rules type function, a compass rose, an erasable writing surface and no moving parts to break.

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Did anyone here actually ever got formal instruction on chart work and laying courses ? I'm astounded


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Perhaps posted as tongue in cheek but yes, I have formal nav traing including chart work etc - both maritime and aviation
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Old 11-03-2015, 02:37   #82
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Re: True or Compas

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Originally Posted by El Pinguino View Post
I've never found that with charts used recreationaly but in the day job.... going up and down the same line night after night would wear a chart out pretty quick. We used to stick Scotch Magic Tape along the course line... that would extend the life a bit.
I see what you did there...

"Very clever, Dr. Jones"
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Old 11-03-2015, 19:25   #83
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Re: True or Compas

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Originally Posted by bill352 View Post
FWIW, the ASA Coastal Navigation Course (105) says to use magnetic.
There are, unfortunately, currently two separate texts. One plots in magnetic and basically ignores corrections (TVMDC)...the other does it right.
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Old 11-03-2015, 20:07   #84
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Re: True or Compas

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Originally Posted by Wotname View Post
I almost exclusively use the Douglas Protractor. Perfect for small areas, contains straight edge, parallel rules type function, a compass rose, an erasable writing surface and no moving parts to break.





Perhaps posted as tongue in cheek but yes, I have formal nav traing including chart work etc - both maritime and aviation

Yes partly torque in cheek , I still astounded though

Dave


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Old 11-03-2015, 22:16   #85
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Re: True or Compas

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Originally Posted by Ex-Calif View Post
Does Opie still fish in the crick? - LOL...
Of course he does.

Who even thought he ever left?
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Old 12-03-2015, 05:33   #86
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Re: True or Compas

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There are, unfortunately, currently two separate texts. One plots in magnetic and basically ignores corrections (TVMDC)...the other does it right.
I am really surprised to hear that. You'd expect consistency from an educational outfit, although by the end of the courses I had a list of problems or mistakes in every single text we used, including "Annapolis Book of Seamanship".

We used Pyzel's "Coastal Navigation" - what is the other one?
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Old 12-03-2015, 07:34   #87
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Re: True or Compas

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Originally Posted by bill352 View Post
I am really surprised to hear that. You'd expect consistency from an educational outfit, although by the end of the courses I had a list of problems or mistakes in every single text we used, including "Annapolis Book of Seamanship".

We used Pyzel's "Coastal Navigation" - what is the other one?
Tom Tursi's excellent text is the "correct" one.

http://store.asa.com/coastal-navigat...ional-dvd.html

This duality of texts is a singular anomaly in the ASA materials. All other classes have a single text. Many of them recently revised (and very well done). I don't know the history of why this anomaly exists.

The venerable "Annapolis..." is not an ASA publication.
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Old 12-03-2015, 08:18   #88
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Re: True or Compas

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Originally Posted by belizesailor View Post
Tom Tursi's excellent text is the "correct" one.

Coastal Navigation Manual (Tursi), Solutions Workbook & Instructional DVD

This duality of texts is a singular anomaly in the ASA materials. All other classes have a single text. Many of them recently revised (and very well done). I don't know the history of why this anomaly exists.

The venerable "Annapolis..." is not an ASA publication.
Thanks. I wish we had used that one.

Don't mean to "blame" ASA for "Annapolis..." mistakes, but they did require it and we did use it.

Delighted to hear that some texts have been revised. As of December 2012, some of them really needed it. Parts of the multihulls text, in particular, could have been turned into a monohull-bashing CF thread and no questions asked.
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Old 12-03-2015, 09:48   #89
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Re: True or Compas

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Originally Posted by barnakiel View Post
On the chart, one can label his line "T=292, M=295" etc. What's the point in arguing as we are talking about exactly the same line being plotted on the chart?

You can plot what you want, it is the same line, just label it correctly and you are fine.

More popcorn, way more...

b.
+1. I've two chart potters now so I rarely plot courses anymore. but I will mark off my position every few hours with my heading (c) and speed(knot meter). back when I used charts exclusively I would use compass or I would even figure in the set and drift and write it on my course line. I want all the math to be done when I'm rested and before I raise my anchor I don't want to be calculating when I'm tired,in the middle of the night or when I've got a million other things to do. And for what it's worth I have a 100 ton license. Edit. That's what works for me but use the method that works best for you. And one more thing if I'm in emergency situation where I have to tell the Coast Guard my heading I will give them course over the ground if I have a GPS if not I will give them my compass heading and tell them that's what it is
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Old 13-04-2015, 17:55   #90
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Re: True or Compas

I just wrote a little calculator App for True, Magnetic, Compass corrections..

I popped it onto iTunes.

https://itunes.apple.com/us/app/tvmd...2780?ls=1&mt=8
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