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 » VO70-v4 and VO70 Polars

Question for Kalle as he part answered my chat question (12/1/09). The old VO70 polar had the 9 and 15 knot wind speed lines showing boat speeds greater than the boat speed shown by the 30 knot wind line for TWA from 0 to 30 and 40 degrees respectively. So we could expect that a current wind speed line from above 6 to 15 knots would likely show intermediate boat speed similarly. The new VO70-v4 polar shows boat speeds for all permanent wind speed lines increasing as the wind speed increases for all angles of TWA. So today I was surprised to see the 21.8 wind speed line plotting outwith the 30 knot line for TWA from 0 to 40. I'm sending a screen shot of the polar. Is the new VO70-v4 polar operating correctly?
Attachments
Hi, well my name is not Kalle but I am a also one of the guys behind the game and maybe I can help. Your observations are correct and I understand your question. The colored curves we have chosen to show does not at all have to show maximum boat speeds, it is in fact extremely unlikely. Thus, your observation is correct and the polar might be "fairly ok too" :-) ok?
...one of the guys behind the game...
Jakob, Thanks for your reply. But looking at your manual, para 1.7 "The boat performance" you imply there that the polar diagram is accurate - e.g. you say "For a certain wind speed and TWA you can read the corresponding boat speed..." Your current response implies that we cannot rely on the boat speed curves you have shown. As I said - the old VO70 polar showed that for lower wind speeds up to 40 TWA we could expect greater boat speed than for the 30 knot wind curve. The new VO70 does not give any indication that the same could occur. Old VO70 attached.
Attachments
Well, two things. 1) The old polar is just that - old. We changed the polar since it behaved a little strangely at low twa:s. The new polar is better in that respect. 2) The actual performance routine in the code is continuous in the sense that the boatspeed can be calulated for all combinations of twa and tws. The graphical representation of that we call the polar is accurate (!) but not showing the boat speed at all combinations of twa and tws. ok?
...one of the guys behind the game...
Thanks Jakob, I guess I have to accept it. Reason I'm so fussy is that as an Excel exercise, I was trying to build an Excel file to help me get best course, and a fundamental of that has been to make a print of the polar and scale off the data, have the Excel do graphs - get equations from these, enter the formulae into a look up table etc etc. I see from your answer to Frank Putman on 15Mar2008 that you don't give out the tabular data, so there's no point in asking you for it I guess.
Well yes, so far we have not given away the tabulated data. if you are doing the interpolation yourself try to use cubic splines in both twa- and tws-directions to get results resembling mine ;-)
...one of the guys behind the game...
Hi Jakob,

Thanks again for your advice. I will see what I can do and maybe will email you with results if I think I'm successful.

Best wishes,

Andy

Please login to post a reply.

Races

Next Race: 00d 00h 00m


Current Races:

Elephant Island to Marquesas 2025

Prepare to test your limits as we launch into the third leg of the RWW Series and the fifth leg of the 2025 Ocean Championship Series—an epic voyage from Elephant Island to the Marquesas in the heart of French Polynesia. This 4,700-nautical-mile challenge is a true test of endurance, strategy, and raw sailing adrenaline. Aboard the high-performance Volvo 70v4, competitors will face fierce headwinds as they round the legendary Cape Horn and make the thrilling transition from the Atlantic to the Pacific. Do you have what it takes to conquer the Pacific? Join us, and put your skills to the ultimate test.
PRIZE: SMPF
Race #1909
INFO by brainaid.de
VO70_v4 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - RWW - OCCH - SUPSOL - SYC
Race starts: May 05th 11:00 Registration Open!
▶ Flash
GO TO RACE

Bosphorus Strait Sprint 2025


Welcome to the Bosphorus for a testing sprint twice through the narrow channel separating the Black Sea from the Mediter-ranean - the traditional bound-ary between Europe and Asia.
Race 1914
INFO by brainaid.de
Dehler 30 OD PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
SPRQ2 - SPRCH - SUPSOL - SYC
Race starts: May 04th 09:00 Registration Open!
▶ Flash
GO TO RACE

Bay to Bay 2025 - Leg 2 - Great Sandy Stait

After a thrilling opener, the 2025 edition of the Bay to Bay Yacht Race continues with Leg 2, bringing even more adrenaline and tactical excitement to the waters of the Great Sandy Marine Park. In collaboration with the Hervey Bay Sailing Club, our SOLers will once again take the helm of their lightning-fast 18-foot skiffs, this time tackling a 24-nautical-mile course through shifting breezes and tight competition.

With fresh legs, sharper tactics, and everything to race for, it’s anyone’s game! See you on the start line for the grand finale!
Race #1906
INFO from brainaid.de
18ft Skiff PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: B2B - SYC
Race starts: May 03rd 21:30 Registration Open!
▶ Flash
GO TO RACE

Bay to Bay 2025 - Leg 1 - Great Sandy Strait

Prepare for an electrifying start to the 2025 Bay to Bay Yacht Race! In partnership with the Hervey Bay Sailing Club, this first leg will see our SOLers take on a fast-paced, 16-nautical-mile sprint through the stunning waters of the Great Sandy Marine Park, weaving past the breathtaking landscapes of the Great Sandy National Park. Racing in high-powered 18-foot skiffs, the fleet will battle shifting winds, tricky tactics, and fierce competition—all in pursuit of victory! With the thrill of the race and an unforgettable sailing experience ahead, we can’t wait to see you on the start line!
Race #1905
INFO from brainaid.de
18ft Skiff PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: B2B - SYC
Race starts: May 03rd 01:00 Registration Open!
▶ Flash
GO TO RACE

Regata dell’Accademia Navale 2025

Welcome to Sailonline’s first partnership with the City of Livorno, in cooperation with the local yacht clubs and the Italian Navy, to offer you the online opportunity to race the Regata dell’Accademia Navale. 630nm in length, starting and finishing in Livorno, the race takes you the length and breadth of the Tyrrhenian Sea via Porto Cervo and Capri. Online, you will be sailing a Class 40, which should keep you well in with the top of the real-life fleet which we will be tracking on screen!
Race #1902
INFO by brainaid.de
Class 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
RACE CLOSE: Friday,
May 9 at 2300 UTC.
Race starts: Apr 27th 09:00 Registration Closed

▶ Flash
GO TO RACE

Transat à Deux 2025

Above you see a single-handed sailor semi-foiling his Beneteau Figaro III to the horizon. It is in fact Ireland’s Sailor of the Year and the overall winner of last year’s Solitaire du Figaro, Tom Dolan. Somehow, we got our hands on a polar for the Class, and rather than trying to surreptitiously track Tom and his mates in the 2025 edition of the Solitaire, sailing rather-short, single-handed legs across the Celtic Sea and Biscay, we thought we’d see how our virtual craft would fare on the Class’s double-handed 3900nm Trans-Atlantic, from somewhere in Brittanny to somewhere in the Caribbean via somewhere in the Canaries. Allez, mes braves!
Race #1901
INFOby brainaid.de
Figaro III foil PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: Apr 20th 11:00 Registration Closed
▶ Flash
GO TO RACE

Sinbad by Balloon 2025 - Toamasina to Baia de l'Oiseau


You may recall that when last we visited Madagascar in the company of Sinbad, the Sultan commanded our intrepid inspirator to seek out fabled islands where in Summer the sun barely set. We did and we returned but the Sultan wasn’t happy with Sinbad’s report, so here we go again, now by SOL Balloon instead of sailing vessel. Expect to be in the air for at least 2100nm and depending on how the wind brings us, anything between two weeks and two months before we shall descend at the Sultan’s given coordinates!
Race #1884
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - SBB
RACE CLOSE: Sunday,
May 18 at 2300 UTC.
Race starts: Apr 09th 11:00 Registration Closed
▶ Flash
GO TO RACE

Valparaiso to San Francisco 2025

Get ready for an exhilarating new challenge as we set sail on the fourth leg of the 2025 Ocean Championship Series! Following in the 19th century footsteps of Isabel Allende's heroine, Eliza Sommers, 'Daughter of Fortune', this all-new route takes us across the vast eastern Pacific, from Valparaíso, Chile, to San Francisco, California - a 3500nm journey of endurance, strategy, and pure sailing adrenaline. This leg will be raced aboard the powerful Rapido 60, pushing sailors to their limits as they navigate the open ocean. Do you have what it takes to conquer the Pacific? Join us and put your skills to the ultimate test!
PRIZE: SMPF
Race #1900
INFO by brainaid.de
Rapido 60 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - OCCH - SUPSOL - SYC
Race starts: Apr 07th 11:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member WRmirekd
  2. Sailonline Yacht Club Member Patrick70119
  3. Sailonline Yacht Club Member CriticalHippo
  4. Sailonline Yacht Club Member FreyjaUSA
  5. Sailonline Yacht Club Member vida
  6. Sailonline Yacht Club Member KaSToR
  7. Sailonline Yacht Club Member rumskib
  8. Sailonline Yacht Club Member Kipper1258
  9. Sailonline Yacht Club Member bonknhoot
  10. Sailonline Yacht Club Member rafa

View full list

Series

Mobile Client

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

The mobile client