In Creating a Route on Charts, Do You Use True or Magnetic ?

[wolfenzee]

Originally Posted by Lodesman

The terms are synonymous. The helmsman steers by compass.

Neat reference (not for navigation): http://upload.wikimedia.org/wikipedi...8/Mv-world.jpg

This thread has drifted to steering with a magnetic compass vs steering with the "compass" on an electronic gizmo set to display a true bearing. I don't care if other people use their electronic toys to steer with, as long as they don't try and convince me that there is something wrong with the method that has been used for hundreds of years.

[boatman61]

Originally Posted by wolfenzee

I don't care if other people use their electronic toys to steer with, as long as they don't try and convince me that there is something wrong with the method that has been used for hundreds of years.

But if everyone was like you... people would be out of a job... tax revenue would suffer... Health and Social Security would suffer... Senators may end up having a pay cut.... lets face it your compass will out last you very likely.... a CP/GPS is dead after a few years.... resales.... commisions earned... bonuses.... more taxes..
you feeling guilty yet...

[wolfenzee]

Originally Posted by boatman61

But if everyone was like you... people would be out of a job... tax revenue would suffer... Health and Social Security would suffer... Senators may end up having a pay cut.... lets face it your compass will out last you very likely.... a CP/GPS is dead after a few years.... resales.... commisions earned... bonuses.... more taxes..
you feeling guilty yet...

If you are trying to say I am not like the majority....I will take that as quite the compliment. Granted our economy is based on "We spend money we don't have, to buy things we don't need to impress people we don't like" and/or "We spend money we don't have to make it look like we do". I am doing something quite Un-American starting, I am starting out the year out of debt (actually with a credit on some major expenditures), I own my own place (not the bank). I am not rich, my income is actually 2/3 the national poverty level.

[boatman61]

Sorry Wolf... guess it lost something in the translation...

[wolfenzee]

I learned about cruising from my father, he was practical and logical, which is why I follow the KISS principle. I find simple to be quite comforting myself.

[peteh007]

Has any one seen a simple App for an iPhone for calculating Magnetic, Variance, True, Deviation, Annual Variation, East-West, blah blah..?

I always make mistakes when I'm tired.. with my TVMDC tables..

If not, I was thinking of writing one.. would anyone be interested in such a simple App?

[peteh007]

I just made a little iPhone App TVMDC calculator that should help folks with this kind of Nav question.... or at least help convert really quickly TVMDC without having to overload on coffee and blank TVMDC tables.. and have a brain that's functionally alive while on passage.. mine stopped working years ago...http://www.cruisersforum.com/images/...s/banghead.gif

I can try to get it up onto iTunes if anyone's interested?

Cheers
p

[peteh007]

I put a little TVDMC App on iTunes..
it saves doing TVDMC tables..

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

[leftbrainstuff]

Mark the route lines with eithr T or M. Doesn't matter what you use as long as you dont mix and match.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[peteh007]

I added Set & Drift and a CTS Quick calculator to the TVMDC app.
It now show's Set & Drift Sailing triangles, CTS triangle and a New TVMDC Compass. you can download it here, if you have an iPhone/pad?

I use it as its very fast to make quick corrections.... the old school method but on a handy iPhone.


https://itunes.apple.com/us/app/curt...067733929?mt=8

[phantomracer]

wow talk about bringing an old thread back Still havent heard from Navico about why my plotter only plots in true. Apparently they dont think anyone plots in magnetic.

I was just curious, when people plot on paper, if they use true or magnetic. seems to be split

[peteh007]

yeah.. charts are all in True.
Compass Roses are in Magnetic
And ships compasses are in 'Compass' magnetic, which tales into account the metal on your boat.
So you have 3 valves.. and have to move in between them.
Hence TVMDC. As sailors all learn when the navigate...

My little App will do this conversion on the fly which saves my tired brain from making mistakes when doing this mental aright in my aging head....

Then you have to ad you Set and Drift correction.. to get you CTS.

And you need to do this quickly sometimes...

Shoot me a note if you ever have Q's?
Cheers!
P

[peteh007]

Novice is a plotter - so it should plot in true. As do all charts.
Only when converting from your chart, to your Course to Steer, do you need to do a wee bit of Math...


take your chart bearing.
your chart CTS is the true heading to Destination
but!!! u Subtract effect of set & drift
and Subtract effect of variance
and Subtract effect of deviation
to get your compass bearing.

it can be off by a LOT!

[Stu Jackson]

Originally Posted by phantomracer

I was just curious, when people plot on paper, if they use true or magnetic. seems to be split

Not so hard.

local distances, daysailing, M

longer distances, GCR = T

[Rustic Charm]

Originally Posted by Stu Jackson

Not so hard.

local distances, daysailing, M

longer distances, GCR = T

wow, just read all 11 pages. I'm a little surprised that so many plot a course in magnetic but each to their own. It really only matters if your traveling a long distance, (and don't have a new fang dangle plotter with GPS) or if your navigating in a plane