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:

Bar-tailed Godwit - Alaska to New Zealand 2026


Welcome to the autumn return flight of our bar-tailed Godwit, reflecting the bird's annual migratory route. This is the penultimate leg in our migration series. (The concluding leg is coming up simultaneously, 'Skimmer Dragonfly', start on the 11th of November. Not part of the 2026 OCCH). This race, at hand, is the next to last leg of the 2026 Ocean Race Championship. The voyage promises to be not only a test of skill and strategy but an immersive experience in the beauty of the vast Central Pacific Ocean. Join us as we push the boundaries of seafaring prowess on this epic adventure.
Let's fly like a Godwit!
Race #2065
INFOby brainaid.de
GunBoat 90 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
OCQ4 - OCCH - SYC - MIG
Race starts: Nov 02nd 11:00 Registration Open!
▶ Flash
GO TO RACE

Mistli's Birthday BBQ Race 2026


It’s that time of year again – November 1, time for Mistli’s birthday bash and BBQ! It’s the usual tricky 61.5nm through the SLI-infested Stockholm Archipelago to Mistli’s place at Trosa, this year in a slightly slower but seriously Swedish Scampi 26!
Race #2063
INFO by brainaid.de
Scampi 26 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RED - SYC
Race starts: Nov 01st 14:00 Registration Open!
▶ Flash
GO TO RACE

ORCV Melbourne to Devonport Race 2026

Welcome to the prestigious Rudder Cup, Australia’s oldest and most iconic yacht race! For over 110 years, this legendary 196nm classic has tested sailors' strategy and endurance across the notorious Bass Strait from Melbourne to Tasmania.

Organized by the Ocean Racing Club of Victoria, this year’s battle against the unpredictable Southern Ocean features the stylish Dehler 46. Designed by Judel/Vrolijk as a proper looker and built to race, this regatta cruiser is a virtual flyer packed with modular racing upgrades. Can you master her speed and conquer the shifting elements?

Chart your course and race for glory in this historic adventure!
Race #2068
INFO by brainaid.de
Dehler 46 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: TQD - SUPBUD - SYC
RACE CLOSE: Friday,
November 6 at 2300 UTC.
Race starts: Oct 30th 03:30 Registration Open!
▶ Flash
GO TO RACE

Mad Max by Balloon 2026 - Across the Outback


Mad Max Rockatansky doesn’t get to go in a balloon in any of the Legends of the Wasteland, and the Wasteland is not necessarily the Outback of Australia, but Mel Gibson and film director George Miller indubitably are… of Australia, and ballooning as reconnaissance is a main feature of the Mad Max spin-off video game, so here goes: 1500nm in a balloon from somewhere on the edge of the Outback, Goondiwindi, to cross a finish line at Fitzroy Crossing, somewhere on the edge of the Outback!
Race #1974
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: BOL - SYC
Race starts: Oct 14th 13:00 Registration Closed
▶ Flash
GO TO RACE

Arctic Tern - Greenland to Antarctica 2026

Welcome to the fifth leg of our MIG series. Now it's time to race the Arctic Terns, on their migration from Greenland to Antarctica, 8300 NM. This is also part of our monthly Ocean Championship, and as such the first race of OCQ4 2026. This race will be sailed in our Maxi Trimaran. Race #2061
INFO by brainaid.de
Maxi Trimaran PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230 Ranking:
OCQ4 - OCCH - SYC - MIG
RACE CLOSE: Wednesday,
November 4 at 2300 UTC.
Race starts: Oct 05th 11:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member KaSToR
  2. Sailonline Yacht Club Member CriticalHippo
  3. Sailonline Yacht Club Member rafa
  4. Sailonline Yacht Club Member rumskib
  5. Sailonline Yacht Club Member cdhinman
  6. Sailonline Yacht Club Member rthinman
  7. Sailonline Yacht Club Member Panpyc
  8. Sailonline Yacht Club Member BRENTGRAY
  9. Sailonline Yacht Club Member brandystrega
  10. Sailonline Yacht Club Member Sax747

View full list

Series

Mobile Client

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

The mobile client