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 » Technical Support » Is the DTG calculation correct

Posted by
mwagg56


Users avatar

Posts
2
Registered at
2009-03-23 23:12:20
2009-05-22 05:03:29 - Is the DTG calculation correct
Is it just me but does the DTG calculation seem incorrect. Seems to be too much north of the rum line!
Posted by
jakob


Users avatar

Posts
364
Registered at
2007-09-04 10:05:30
2009-05-22 05:46:31 - Re: Is the DTG calculation correct
DTG is calculated along a great circle (shortest way) and not the along rhumb-line (constant course). ok?
...one of the guys behind the game...
Posted by
mwagg56


Users avatar

Posts
2
Registered at
2009-03-23 23:12:20
2009-05-22 05:59:59 - Re: Is the DTG calculation correct
I understand. However, checking with the great circle tool suggests that the DTG for boats above the rum line is incorrect. eg STU131270 is reading around 917nm to go but the great circle tool suggests the true distance is about 100 nm less.
Posted by
jakob


Users avatar

Posts
364
Registered at
2007-09-04 10:05:30
2009-05-22 06:42:53 - Re: Is the DTG calculation correct
DTG-calcs over long ranges when rounding of waypoints are involved are tricky. Just be cool and things will sort out as you get closer, I promise.
...one of the guys behind the game...
Posted by
Incognito


Users avatar

Posts
183
Registered at
2008-12-06 13:43:52
2009-05-22 07:34:48 - Re: Is the DTG calculation correct
Hi SOLer's,

I have just opened a similar thread. Sorry to repost here.

Jakob, I do not want to be mean, but you seem to be in denial. ;-)

According to SOL, at 7:00 UCT, I was ranked 86th with more than 674 NM to go.

In brainaid's ranking however (http://sol.brainaid.de/pub/ranking-145.html), I was ranked 14th with 637 NM to go.

Quite a difference! And when I use the pliers or the pointer to calculate the DTG, I come to a figure similar to brainaid's.

We had similar issues in led 5. Personnally, I remain convinced that there is an error in the formula used to calculate the DTG in SOL's ranking. It would be nice to fix that sometime.

Regards,

Francois on Incognito

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Newport Bermuda Race 2026


The 636-mile Newport Bermuda Race is one of the oldest regularly scheduled ocean races, and with the Fastnet and the Sydney Hobart Race, it is one of the three great classic races of the yachting world. First raced in 1906, now in its 54th biennial, the Race can again also be participated in online. In real life, the race is open to entry in four different division – Double-Handed, St. David's Lighthouse, Gibbs Hill Lighthouse, and Finisterre Division – which in the past we have also offered online. This year, however, our online race will be all-in one-design in silky swift Club Swan 50 yachts, so that your results can count towards SOL’s SUPerBUDdy title, whilst hopefully still giving you a chance of overall line honours against the fastest yachts of the real-life Gibbs Hill Division, especially if you can find some forecast winds that don’t quite work out that way on the real water!
Race #2038
INFOby brainaid.de
Club Swan 50 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SUPBUD - SYC
Race starts: Jun 19th 17:05 Registration Open!
▶ Flash
GO TO RACE

Bluefin Tuna - Mexico Gulf to North Sea 2026

Join us and follow the Bluefin Tuna, as they migrate from their spawning grounds in the Gulf of Mexico to their feeding grounds in the North Sea off the coast of Norway. This 4300 nm race is part of our Ocean Championship and the final race of OCQ2 2026, and also the second leg of our Migration series. We will be sailing in our Gunboat 90. Race #2035
INFO by brainaid.de
Gunboat 90 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - MIG - OCCH - SYC
Race starts: Jun 08th 11:00 Registration Open!
▶ Flash
GO TO RACE

Thessaloniki to Port Said 2026

Welcome back to the Eastern Mediterranean for the fifth race of our Magical Mediterranean Series. Only marginally less unlikely to be ever raced in real life during SOL’s lifetime than our previous race from Tobruk to Iskenderun, this 710nm race takes us from Greece’s ancient northern port of Thessaloniki through the Aegean island maze, south east into the Levantine Sea to a finish in modern Port Said, in splendid Swan 65s!
Race #1977
INFO by brainaid.de
Swan 65 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: MED - SYC
RACE CLOSE: Wednesday,
June 17 at 2300 UTC.
Race starts: Jun 06th 15:00 Registration Closed

▶ Flash
GO TO RACE

TuziTekwini TIMED Race 2026

Sailonline is delighted to have been invited again to partner with the King Shaka Yacht Club (KSYC) of South Africa to bring a virtual version of the Tuzi Tekwini Ocean Raceto our online community.
The Tuzi Tekwini Ocean Race is a near 90 nautical mile race down the east coast of South Africa from the port of Richards Bay to the port of Durban. Achievable in a single day and seen by some as an easy mile-builder, the course is more tactical than some think and should not be underestimated. This iconic race promises to be an unforgettable experience for yachting enthusiasts.
Our online version of the race will be a TIMEDrace so you may RE-REGISTER HEREto try again after finishing a run. You will have two weeks to test your skill and decision making after the race opens.
Race #2037
INFOby brainaid.de
Sailonline’s virtual yacht for all your runs will be our much-loved Farr 38 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ2 - TRCH - SUPBUD - SYC
RACE CLOSE: Saturday,
13 June at 23:00 UTC
Race starts: May 31st 12:00 Registration Open!
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member WRmirekd
  2. Sailonline Yacht Club Member KaSToR
  3. Sailonline Yacht Club Member CriticalHippo
  4. Sailonline Yacht Club Member bonknhoot
  5. Sailonline Yacht Club Member rafa
  6. Sailonline Yacht Club Member Panpyc
  7. Sailonline Yacht Club Member HoratioPugwash
  8. Sailonline Yacht Club Member YANN
  9. Sailonline Yacht Club Member CollegeFund
  10. Sailonline Yacht Club Member sassy63

View full list

Series

Mobile Client

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

The mobile client