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 » Something weird happened at Sydey TSR

Posted by
JakeS


Users avatar

Posts
18
Registered at
2012-09-25 16:23:40
2013-10-09 17:02:40 - Something weird happened at Sydey TSR
I try to set my boat to cog 262.2... (to get to pr start) and that kind of predictor line came up (see pic). I try twice, same both times . . . and as you can see my bs is -0,03 and twa is 51.65 :)
Attachments
Posted by
RainbowChaser


Users avatar

Posts
2656
Registered at
2009-06-14 09:44:50
2013-10-09 17:11:37 - Re: Something weird happened at Sydey TSR
As discussed in race chat - there is nothing weird (fortunately)... its just how tall ships are. Best VMG is around + / - 72d :-)
________________

--- Last Edited by RainbowChaser at 2013-10-09 17:12:16 ---
Posted by
JakeS


Users avatar

Posts
18
Registered at
2012-09-25 16:23:40
2013-10-09 17:19:34 - Re: Something weird happened at Sydey TSR
Sorry my mistake. Was just thinking that twa +50 usually move you boat forward not backward. Did not remember that we sail by TSR boats :)
Posted by
kroppyer


Users avatar

Posts
347
Registered at
2010-02-05 15:25:55
2013-10-09 18:08:00 - Re: Something weird happened at Sydey TSR
The square rigger polar contains negative speeds. This was, as far as I can tell, not intended. I think it's a result of the spline calculation that was used to create the polar. The designer probably set some values like
twa -> sog
0 -> 0
20 -> 0
40 -> 0
55 -> 0
60 -> 0.3
65 -> 2.3
70 -> 4.3

And then the computer was used to make a smooth line through these points to determine the values in between. The algorithm that did the smoothing was not told it could not use negative values to make the line smooth.

Tall Ships are probably the only polars that have this, as no other boat would have a SOG of 0 when TWA != 0

.. ok, that was a poor explanation... but I added a nice colourful picture to make you all happy again :)
It's the polar, zoomed in to the centre, you can see the loops that were the result of the spline calculation.

--- Last Edited by kroppyer at 2013-10-10 05:10:39 ---
Attachments

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Cross the Convergence 2026 - Robinson Crusoe to Galapagos


Welcome to our first race of a new series of ocean voyages across the World’s convergence zones, this first race taking you north from south of the Tropic of Capricorn to the Equator-straddling Galapagos, home of magical iguanas and other exotic fauna (but no mythical kings, Dory) Departing from the island where in 1704 adventurer Alexander Selkirk inspired Daniel Defoe to write the best-seller "The Life and Adventures of Robinson Crusoe", by debarking off the unsound "HMS Cinque Ports", four months before she foundered off the coast of present-day Colombia, we will sail the 2200nm in our decidedly sounder and faster than the " Cinque Ports",
Ocean 50 !
Race #1983
INFOby brainaid.de
Ocean 50 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: CCZ - SYC
Race starts: Jan 16th 18:00 Registration Open!
▶ Flash
GO TO RACE

Bight of Bonny TIMED Race 2026

Welcome to the first TIMED race of 2026! Our race finds us in the Gulf of Guinea and the Bight of Bonny. Starting in Douala, Cameroon the 170 nm course takes us around the island of Bioko with its Caldera and tropical rainforests finishing in Calabar, Nigeria. The boat for this race is the sporty Farr 30. This is a TIMEDrace so you may RE-REGISTER HEREto try again after finishing a run. You will have 13 days and 11 hours to test your skill and decision making after the race opens.
Race #2004
INFOby brainaid.de
Farr 38 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ1 - TRCH - SYC
RACE CLOSE: Saturday,
24 January at 23:00 UTC
Race starts: Jan 11th 12:00 Registration Open!
▶ Flash
GO TO RACE

Natuna Sea Race 2026


At 4.0N 108.2E lies the island of Natuna Besar, Great Natuna, surrounded by at least 154 islands, of which 127 uninhabited, Indonesia’s Natuna Regency, and all around this archipelago, the Natuna Sea, bordered by Borneo to the east, the Java Sea to the south, and the Malay peninsula to the west, and extending north to cross a disputed international border with China into the South China Sea. And it’s a border that matters, there’s gas here! But why worry, let’s race – 2050nm in our goo’ol’ Open 60s in between the production platforms, prowling destroyers and submarines.
Race #1997
INFOby brainaid.de
Open 60 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: Jan 06th 17:00 Registration Closed
▶ Flash
GO TO RACE

Cape Town to Rio 2026

Welcome to South Africa and RCYC's classic transatlantic Cape2Rio Race from Cape Town, South Africa, to Rio de Janeiro, Brazil. First run in 1971, this run is buddied with the IRL, Cape2Rio 2025 arranged by the Royal Cape Yacht Club with the cooperation of the
Iate Clube do Rio de Janeiro Despite this being announced the 2025 race (starting dec. 27) it is the 2026 SOL championship kickoff. This virtual version, will be raced once again in Mark Mills' 74ft speedster, the stunning C2R74.
Race #1996 INFO
by brainaid.de
C2R74 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
OCQ1 - OCCH - SUPBUD - SYC
Race starts: Dec 27th 12:00 Registration Closed

▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member KaSToR
  2. Sailonline Yacht Club Member WRmirekd
  3. Sailonline Yacht Club Member CriticalHippo
  4. Sailonline Yacht Club Member rafa
  5. Sailonline Yacht Club Member vida
  6. Sailonline Yacht Club Member bonknhoot
  7. Sailonline Yacht Club Member Sax747
  8. Sailonline Yacht Club Member rumskib
  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