Facebook

Login

Support Sailonline

If you haven't already - join the SAILONLINE YACHT CLUB!

Please also consider making a donation - all amounts are greatly appreciated!

Board » General Discussion » Great circle-explanation please?

Posted by
Jepsom


Users avatar

Posts
30
Registered at
2008-01-28 20:27:15
2010-05-08 18:16:12 - Great circle-explanation please?
Hi

I´m not the best it-guru and I don´t understand all this about the Great Circle. So, can someone please explain way this happens. If you steer 270 degree west and then turn back, vs. rate, east 90 degrees. Why don´t you come back to the point from where you started?
Attachments
Posted by
jakob


Users avatar

Posts
364
Registered at
2007-09-04 10:05:30
2010-05-08 19:50:16 - Re: Great circle-explanation please?
The great circle is the shortest line between 2 points on the globe. (tip: play with a thread and 2 needles on an orange). This means that the course along a GC typically changes along the path. The courses in your examples are the courses to set at the turning points. Along the rest of the paths, the courses are different. Hence, your question is a little oddly put since you seem to refer to a loxodrome when you state that you steer a certain constant course. Tip 2: Zoom out a lot and play with the measuring tool and you will likely see what I mean.
...one of the guys behind the game...
Posted by
Jepsom


Users avatar

Posts
30
Registered at
2008-01-28 20:27:15
2010-05-08 21:09:14 - Re: Great circle-explanation please?
I hope that you do not think my question was a critical one...
And My Q was not "little oddly" :)))
I am a single Coca-Cola Salesman and no academics. So thats why I ask for things that I do not understand. I understand that it is the most direct route between two points on the globe, but became confused when I measured as in the example. Now you have explained and I have done my homework so that I will be more toxic than in the future;))
If you wonder about the difference between Coke Zero and Coke light, I will be the first to tell you ...;))


Thank! :)
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2010-05-09 01:19:39 - Re: Great circle-explanation please?
"Oddly little" the whole question is by being not able to open attachments in question.

It's fun though to put a face to Jepsom :)

Nice example of how the GC tool in SOL measures angles! Slightly unexpected, but no straight lines on this orange... Try it with CC.

We used to have a coke C2 that had 1/2 sugar but also artificial sweeteners... Maybe our resident guru can explain why they don't make it with 1/2 sugar but no compensatory chemicals for those of us who might like such a thing mixed with rum? ;)

--- Last Edited by 76Trombones at 2010-05-09 01:29:47 ---
Posted by
jakob


Users avatar

Posts
364
Registered at
2007-09-04 10:05:30
2010-05-09 06:24:38 - Re: Great circle-explanation please?
No problem Jepsom. These questions are very good in several ways. They makes us reflect on how the user interface works, how clear the manual is etc... Also, if you have such a question I bet there are 100 others wondering the same thing :-)

My only Coke-question is: Can I get the recipe please?

/Jakob
...one of the guys behind the game...
Posted by
Jepsom


Users avatar

Posts
30
Registered at
2008-01-28 20:27:15
2010-05-09 07:38:56 - Re: Great circle-explanation please?
Well...

First, 76: I will forward your question to the main office. While you wait for an answer, you may drink only Rome ... if you doubt the content ..;)

And Jakob: It´s all about money I think.. :)

Ps. It´s fun to put a face to 76trombone as well... I do understand you wife... ;) Ds.

/Jesper

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

The Vineyard Race 2025


For the first time since first hosting a virtual Vineyard in cooperation with Long Island's Stamford Yacht Club back in 2010, due to an operational calendaring error, Sailonline has missed the start of the real life race, the USA’s Labor Day weekend this year unusually falling across the turn of August. Silly SOL! So, a week late please join us anyway for a virtual rerun of Stamford’s iconic annual overnighter from their club line out the sound to Buzzard's Bay Light near Martha's Vineyard Island and back again, leaving Block Island to starboard. This year, Sailonline is making its magic MC 38 available to competitors, a race boat with a quirky polar that will require you to stay wide awake as you speed around the c 250 nm course, in rockstar style!
Race #1946
INFO by brainaid.de
MC 38 PARTICULARS
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC
Race starts: Sep 06th 17:05 Registration Open!
▶ Flash
GO TO RACE

Great Nicobar to Marion Island 2025

The Adventure Continues – Leg #6 of the RWW Series.
We’re setting sail on the next stage of the RWW Series: a 4,400-nautical-mile passage from Great Nicobar to Marion Island. This demanding leg will test endurance, strategy, and seamanship at the highest level. As part of the 2025 Ocean Championship, this marks the ninth legendary challenge in the series — and one of the most exhilarating yet. The race will be contested aboard the Archer 78’ ketch, a vessel built to push sailors to their limits across the vast Indian Ocean.
PRIZE: SMPF
Race #1942
INFO by brainaid.de
Archer 78 PARTICULARS    
WX Updates:
0430 / 1030 / 1630 / 2230    
Ranking: OCQ3 - RWW - OCCH - SUPSOL - SYC
Race starts: Sep 01st 11:00 Registration Open!
▶ Flash
GO TO RACE

SSANZ Triple Series 2025 - Race 3

Welcome to the grand finale of this year's SSANZ Triple Series! The stage is set for the Lewmar 50, a thrilling 39nm challenge tracing the southern shores of the stunning Waiheke Island, pushing out to Tarahiki before the sprint back to Islington Bay. Expect fast legs, tactical battles, and no shortage of drama as our SOLers take on the waters in their Young 88s, lining up once again against the talented IRL members of the Young 88 Association. With the series on the line and everything still to fight for, it all comes down to this final race!
Race #1934
INFO by brainaid.de
Young 88 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
SSANZ - SYC
RACE CLOSE: Wednesday,
September 3 at 2300 UTC.
Race starts: Aug 29th 21:15 Registration Closed
▶ Flash
GO TO RACE

Africa by Sea 2025 - Maputo to Mogadishu


The fifth leg of our exploration of Africa By Sea takes us north along the length of the Continent’s succulent sub-tropical and tropical Indian Ocean coast. Much fought over by traders and colonists both well-before and after a Portuguese expedition under the command of Vasco da Gama first sailed there from Europe back in the 16th century, it is yet to be properly explored as a yachting destination. With plenty of islands off- and inshore, small and very large, there is much to interrupt your 1900nm voyage and visit in your Swan 65, from Maputo to Mogadishu! Race #1858
INFOby brainaid.de
Swan 65 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - ABS
RACE CLOSE: Saturday,
September 6 at 2300 UTC.
Race starts: Aug 20th 17:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member WRmirekd
  2. Sailonline Yacht Club Member CriticalHippo
  3. Sailonline Yacht Club Member vida
  4. Sailonline Yacht Club Member rafa
  5. Sailonline Yacht Club Member KaSToR
  6. Sailonline Yacht Club Member Kipper1258
  7. Sailonline Yacht Club Member BRENTGRAY
  8. Sailonline Yacht Club Member Sax747
  9. Sailonline Yacht Club Member CollegeFund
  10. Sailonline Yacht Club Member Panpyc

View full list

Series

Mobile Client

SYC members have the benefit of access to our mobile/lightweight web client!

The mobile client