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 » Compute Optimal VMC and more

Page: Previous 1 2 3 Next

Posted by
AGage


Users avatar

Posts
411
Registered at
2008-12-27 10:31:57
2012-05-09 09:54:08 - Re: Compute Optimal VMC and more
Rod said @ 2012-05-06 00:51:59:
Agage' I don't understand the theory behind your new tool---Do you care to conduct a seminar on the care and feeding of such an exotic 'animal'?
=============================
Not really a seminar, but on the Links page above the 3 Blogs - by 76T, SWE54 and myself all have articles on VMC and VMG - and mine has links to yet more articles
I help develop the client interface for the best online ocean racing sim there is... __/)/)_/)__
Posted by
K3 (Bernd)


Users avatar

Posts
130
Registered at
2008-08-25 12:34:07
2012-05-09 20:13:45 - Re: Compute Optimal VMC and more
Hi Aaron,

thanks for your detailed answer, the tool itself and V2!

My browser looses the connection, when I set the iMac asleep. When it wakes up, the red time display appears for some seconds until the new connection is established. The AngleTools (V1) misses the re-connection sometimes (and doesn't shows it).

I try to explain the %-thing. When I want to go a higher or lower than opt VMC or VMG I can enter for example 95% BB or SB in my own xls-sheet and get a TWA that takes care of bumps in the polar better than a fixed offset from the opt TWA.

ciao
Bernd (K3)
Posted by
AGage


Users avatar

Posts
411
Registered at
2008-12-27 10:31:57
2012-05-10 06:52:07 - Re: Compute Optimal VMC and more
I cant really think why the tool shouldnt reconnect to, but it does use different code to handle the boat updates (I just pinched the polar code from the client - everything else is new)

Cant figure quite what 'BB' and 'SB' stand for....

I did have in mind to add ability to constrain TWA for VMC calculations (mostly for bumpy polars as you mentioned)
Would this give the same effect? Ie you could constrain TWA to be within 100-140. Often times the answer will just be with 100 or 140, but with bumpy polars setting the TWAs either side of a bump can produce results somewhere between the constraints
I help develop the client interface for the best online ocean racing sim there is... __/)/)_/)__
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2012-05-10 13:08:04 - Re: Compute Optimal VMC and more
My guess is

BB = Boat Bearing
SB = Speed of Boat
None so blind
Posted by
Schakel


Users avatar

Posts
183
Registered at
2008-12-19 09:19:00
2012-05-10 14:56:07 - Re: Compute Optimal VMC and more
My guess is

BB = Port (Backbord)
SB = Starboard (Steuerbord)

--
Cheers,
Philip

--- Last Edited by Schakel at 2012-05-10 14:58:42 ---
Posted by
AGage


Users avatar

Posts
411
Registered at
2008-12-27 10:31:57
2012-05-14 11:16:33 - Re: Compute Optimal VMC and more
A Flash version is now available online here
This version has a nice 'Cobalt' theme to!!

This is the original version, hence only supports logging into a single race, but unlike the AIR version, you can open more than one instance.

I help develop the client interface for the best online ocean racing sim there is... __/)/)_/)__
Posted by
captjack1942


Users avatar

Posts
239
Registered at
2008-01-18 03:24:03
2012-05-21 22:19:42 - Re: Compute Optimal VMC and more
Funny thing about the stand alone widget tool. It seems fond of giving TWA as NN.99 or NN.49. At least it seems that is all I ever see.
The flash version at least isn't derived from a fuel station pump price.

:-)
Posted by
AGage


Users avatar

Posts
411
Registered at
2008-12-27 10:31:57
2012-05-23 07:34:43 - Re: Compute Optimal VMC and more
Can you send me a screenshot or something Jack?

And please, be a little more specific, ie TWA for what calculation? All of them, or just VMC to a heading or what?
I help develop the client interface for the best online ocean racing sim there is... __/)/)_/)__
Posted by
captjack1942


Users avatar

Posts
239
Registered at
2008-01-18 03:24:03
2012-05-23 15:31:30 - Re: Compute Optimal VMC and more
Doesn't seem to be doing it now. But I swear for the last two short races (Aland and Perth) it would give TWA as a decimal .99 90% of the time and .49 the other 10%. Either VMC to next mark, course or a WP that I entered. I would get something like Port:...TWA=-55.99...

:-)
Posted by
AGage


Users avatar

Posts
411
Registered at
2008-12-27 10:31:57
2012-05-24 08:41:38 - Re: Compute Optimal VMC and more
Bear in mind that internally the program is comparing velocities computed to some 10 decimal places - as is the SOL client and server.
Quite often it happens that the TWA for max vmg or vmc is a whole number (or atleast is displayed as 142.00 or whatever)
The program just loops over all possible headings or TWAs, incrementing by 0.01°, and reports which has the highest value - which can sometimes be angles like 40.68 for upwind vmg...

If it is consistently giving result of N.99 or N.49 - just think of this as (N+1).00 or N.5 but because of the precision of the values as held internally, it is probably well beyond the 4th decimal place that this angle is faster
I help develop the client interface for the best online ocean racing sim there is... __/)/)_/)__

Page: Previous 1 2 3 Next

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Viareggio Bastia Viareggio 2026

Our sixth race of nine to celebrate all things Mediterranean - fickle winds, history and olive oil - was planned to be our third buddy-up with another incredible Italian event, the Viareggio Bastia Viareggio (or BVR for short). Unfortunately, in-real-life the BVR has been cancelled this year. But online we shall race it never the less. It’s a quickie – a 160nm roundtrip there-and-back in classic Class 40. Have fun, and if you’re planning a BBQ, piccola isola Capraia halfway across is simply lovely!
Race #2041
INFO by brainaid.de
Class 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: MED - SUPBUD - SYC
Race starts: Jun 24th 12:00 Registration will open soon

▶ Flash
GO TO RACE

Shetland Race 2026 - Leg 2


After the thrill of the first leg, we don't linger long in Lerwick, Shetland. Following brief but joyous celebrations, it's time to set sail back across the North Sea to Bergen, Norway, for the gripping second leg of the Shetland Race 2026!

Covering another unpredictable 190 nautical miles, tactical depth and fierce competition await. This year, we take the helm of the Linjett 33. Designed by Mats Gustavsson in 1994 for Sweden's historic Rosättra Båtvarv, this sturdy, quality cruiser-racer has been a Sailonline favourite in northern waters since 2010. Whether you are chasing victory or savoring the voyage, hoist your sails and let the journey home begin!
Race #2040
INFO by brainaid.de
Linjett 33 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
SHE - RED - SUPBUD - SYC
Race starts: Jun 20th 16:00 Registration Open!
▶ Flash
GO TO RACE

Brisbane to Keppel Tropical Yacht Race 2026


When the winter weather turns cool in southern Australia, sailors head up to the warmer tropics. Sailors from all over the world make their way to The Great Barrier Reef for the big winter regattas at Hamilton Island, Airlie Beach and Magnetic Island.
This year's B2K will start on 20 June to offer an event suited to a broader range of boats. Sailonline is, once again, joining with the racers from RQYS to race the 343 nautical miles from Brisbane to Keppel Island, this time in our First 44.7. It might be winter down under, but all you will need is shorts and t-shirts.
Race #2026
INFO by brainaid.de
First 44.7 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SUPBUD - SYC
Race starts: Jun 20th 01:00 Registration Open!
▶ Flash
GO TO RACE

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

Shetland Race 2026 - Leg 1


Get ready to tackle the North Sea as we sail from Norway’s stunning outer Korsfjorden to the rugged Shetland Isles! Welcome to an exciting new chapter for this classic 190-nautical-mile ocean route, bringing our global community together for a true test of strategy and seamanship.

This year, the race is a proud stop in Sailonline's 2026 Super Buddy Championship, which features our real-life racing partnerships over the calendar year. We are stepping aboard the Linjett 33, a sturdy Swedish cruiser-racer designed by Mats Gustavsson and built by Rosättra Båtvarv. Seasoned veteran or eager newcomer, prepare for intense competition.

Plot your course and see you at the start line!
Race #2039
INFO by brainaid.de
Linjett 33 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
SHE - RED - SUPBUD - SYC
Race starts: Jun 17th 11:00 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 Closed
▶ 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 sassy63
  10. Sailonline Yacht Club Member ms0689

View full list

Series

Mobile Client

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

The mobile client