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Board » General Discussion » Navigation problrm

Posted by
etxnebe


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6
Registered at
2007-12-23 10:29:47
2008-06-01 19:16:32 - Navigation problrm
If I set a course on the goal line I expext to end up in the goal not 15 nm to the north. I had activated Great circle navigation and saw tyhat the course line was curved but when I
checked why my boat was stranded I saw
that it had sailed in a stait line not as shown on the map when a doid set the course (last rare to Boston previouse race same problem on Hawai).

Can anybody telll me the purpose with great circle navigation idf the boat do not follow the coures set.

Looking forward to some good piece of advise in this matter.

Regards

ETXNEBE
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Posted by
clash


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2007-11-20 20:10:24
2008-06-02 14:38:23 - Re: Navigation problrm
Hi etxnebe!
Great circle course is not a "straight" line as CC are!
Following a GC course forces you to change CC now and then.
Try to use the ruler and click along the May Transat rhumbline every 250Nm for example. You will find that you have different CC in most of the "boxes" created by each click!
Any help to You?
clash2
Posted by
Tomas


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Registered at
2007-08-10 09:15:02
2008-06-02 14:45:59 - Re: Navigation problrm
Hi!
Great circle nav is just so you can see the "bent" closest route over earth a flat earth and with the course tool pick the initial course.
Lust like in real life you have to alter course manually to follow the great circle.

Compass course is just a angle from magnetic north.

Posted by
Jeroen


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Registered at
2007-08-15 09:17:47
2008-06-03 12:02:45 - Re: Navigation problrm
Yeah both remarks are correct.

Great circle nav will give you a indication how your track would be like if you optimize it to take in account the earths bend.

I can understand your confusion becouse it gives a bit the impression this will be the actual course. As said this will require constant adjustments allong the path.

Hope this helps to clear up, sorry to hear you mist the finnish by this.



--- Last Edited by Jeroen Tiel at 2008-06-03 12:03:15 ---
I am a ex-admin of SOL who joins in from time to time.
Posted by
etxnebe


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6
Registered at
2007-12-23 10:29:47
2008-06-03 18:50:05 - Re: Navigation problrm
Hello!

Thanks for all the good explanations to my problem. Shall I conclude this matter by saying that if I set a strait cource to the finish line(no Great circel nav. on) the system will get me there but not on the shortest way. If I use Great circle navigation I will get the shortest way but I have to update the compass cource in regular intervalls to hit the target.

Very best regards

Etxnebe

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