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:

Africa by Sea - Abidjan to Swakopmund


Our exploration of Africa by Sea continues. Next, it’s off to Swakopmund, on the water’s edge of the Kalahari desert. It’s a wind-blasted coast, and a venue of choice for those seeking to set wind-powered speed records. More likely than not, we’ll have to beat into it in our Steinlager II, to finally find some shelter behind the walls of Platz am Meer where there is a marina of sorts. Only 2200nm!
Race #1856
INFOby brainaid.de
Steinlager II PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - ABS
Race starts: May 14th 17:00 Registration Open!
▶ Flash
GO TO RACE

Newport to Annapolis 2025


The Newport to Annapolis race, first held in 1947, is one of the most historic and well-known US East Coast blue water races. Linking two seaports dating from the US nation's birth, Annapolis and Newport, the race contrasts the country's largest estuary, the Chesapeake Bay, and the Atlantic Ocean. Since 1969, the route has run from Annapolis through the Chesapeake Bay to Newport. The SOLers will sail 470nm in their Carkeek40s in the original direction from Newport to Annapolis, including the Chesapeake, which is such a daunting challenge that the 1997–98 Whitbread Round the World Race for the Volvo Trophy added it to the course, as did the Volvo Ocean Race in 2002 and 2006.
Race #1912
INFO from brainaid.de
Carkeek 40 PARTICULARS
WX Updates:
0245 / 0845 / 1445 / 2045
Ranking:
ARQ2 - ARCH - SUPSOL – SYC
Race starts: May 12th 17:00 Registration Open!
▶ Flash
GO TO RACE

Channel Islands TIMED Chase 2025

Join us in Saint Peter Port, Guernsey for a race around the Channel Islands in the J-109, a recent addition to the Sailonline fleet. The course takes us around the islands of Alderney and Jersey finishing back in Saint Peter Port. This is a TIMED race, so you may RE-REGISTER HERE to 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 #1915
INFO by brainaid.de
J-109 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ2 - TRCH - SUPSOL - SYC
RACE CLOSE: Saturday,
24 May at 23:00 UTC
Race starts: May 11th 12:00 Registration Open!
▶ Flash
GO TO RACE

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 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 CLOSE: Thursday,
May 15 at 2300 UTC.
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

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 KaSToR
  5. Sailonline Yacht Club Member FreyjaUSA
  6. Sailonline Yacht Club Member rafa
  7. Sailonline Yacht Club Member Kipper1258
  8. Sailonline Yacht Club Member vida
  9. Sailonline Yacht Club Member bonknhoot
  10. Sailonline Yacht Club Member rumskib

View full list

Series

Mobile Client

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

The mobile client