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 Discussion » Performance loss

Page: Previous 1 2 3 4 5 6 7 Next Last

Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2013-10-11 01:27:15 - Re: Performance loss
I just did two gybes in a row in the start of the Kergulen timed race. In the first I forgot about the 93% and my perf dropped below 85%. I started the second gybe with a perf of 89% and stepped around in about 4 or 5 steps, completing my gybe at a perf of 90% increasing my perf at each step.
I contend this is vital information that should be known to all, that it cannot be derived by direct observation, or by prior knowledge of how a sailboat performs in reality!
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2013-10-11 13:10:37 - Re: Performance loss
These discussions have occurred in the past but it tends to run in cycles so that when it re-emerges often what was once public knowledge can subside into a quasi state of urban lengend.

Finding these nuggets in this Forum can be a challenge even if you are looking for something that you yourself have posted.

=========================
Wrong Speed VMG

Posted by
Jakob Kuttenkeuler
2009-02-09

(discussing performance loss model)

"Well, the current model determines
if the maneouver is a tack or a gybe
or just a minor change in twa
(dTWA is the twa change).
If (tack or gybe)
{e = 1.0-self.bs/200.0}
else
{e = 1-abs(dTWA)/25.0}.
perf = perf*e.
However if perf<0.93
no further maneouver loss is done. something like that."

--- Last Edited by A2R at 2013-10-11 13:48:19 ---
None so blind
Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2013-10-11 14:29:14 - Re: Performance loss
Many thanks, A2R!!!!
That is the information that we should have had right at the beginning of this whole discussion. I hope that it will be incorporated in the Manual in a prominent position.
I have inquired about the perf loss problem several times over the last three four years and, until now, never received even a hint of an answer
P.S. I will attempt to generate a diagrammatic representation of this situation for the benefit of those among us who are more comfortable with diagrams than equations.
P.P.S. Now all we need to find out is the rate at which the Performance returns to 100% after a Tack, Gybe, or Course Change.
I do hope someone will post the info---in the meantime I will experiment in the Kergulen screen (there are no good windows in the time remaining.)

--- Last Edited by Rod at 2013-10-11 14:33:17 ---

--- Last Edited by Rod at 2013-10-11 14:41:56 ---
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2013-10-11 14:41:26 - Re: Performance loss
Well depending on your Point of View it was either hiding in plain sight or it was a needle in the haystack, so to speak.

I found it because I went looking for it, plain & simple, as anyone could have done.


None so blind
Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2013-10-11 14:59:10 - Re: Performance loss
You can only look for things that you suspect do exist. My point is that there is nothing in the performance of a sailboat during a change in course that would lead anyone to suspect that the loss of speed would be reduced by dividing the course change into two steps.
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2013-10-11 15:16:09 - Re: Performance loss
I neither knew that it existed or that it did not exist. Looking is a choice as is not looking. I found more than I expected to, so let's move forward from here.
None so blind
Posted by
captjack1942


Users avatar

Posts
239
Registered at
2008-01-18 03:24:03
2013-10-11 16:32:10 - Re: Performance loss
Rod said @ 2013-10-11 14:59:10:
"You can only look for things that you suspect do exist."
No accounting for Serendipity, eh Rod?
;-)
Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2013-10-11 18:25:24 - Re: Performance loss
Relying on Serendipity makes you a "Prince of Serendip". I am no 'prince'...science does not rely on just good luck. It needs observation, reasoning, and experimentation. Good luck may happen---then you win the lottery and don't have to worry about anything except greedy relatives.......
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2013-10-11 18:37:05 - Re: Performance loss
Initiative often succeeds where rationalization cannot.
None so blind
Posted by
WIN


Users avatar

Posts
349
Registered at
2009-07-09 23:32:07
2013-10-11 18:40:38 - Re: Performance loss
ciao ALL my friends ;)

just a little contribution from me on this subject :

I remember a few years ago a french soler discovered that jybing in several steps was reducing the perf loss, so I tried to see how it worked ......I did it once only and never again .

two main reasons for that :

1) by so doing the boat runs a longer course , and some of your perf loss saving is gone already, and the time at lower speed below VMG during the maneuver eats away another portion of the saving

2) ( and this is the main reason ) ....after the jybe your angle towards the next mark will no longer be the same and could be worst .......for longtime.

It is very true that also the contrary of item 2) may occur , but item 1) still stands .

IRL an offshore jybe is " smoothed" not so much for performance , but maily for smoothing the maneuver by the crew and keep the spi flying ......whilst , in-shore jybing around a mark smoothing the jybe could cost a number of positions .

Hope you all accept it as an opinion and contribution ..

ciaooooooooooooo ;) ;) ;)

Piero

PS : I did win quite a number of races in SOL , but never because I smoothed jybing or tacking to reduce perf loss..;)

Page: Previous 1 2 3 4 5 6 7 Next Last

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

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 starts: Apr 26th 10:00 Registration Open!

▶ Flash
GO TO RACE

Gulf of St Lawrence 2025


The Gulf of St. Lawrence, with one of the largest and deepest estuaries in the world, will be the site of a completely new race in SOL. Our Melges 40 will take us 950 nm from Bathurst in Baie des Chaleurs around the islands of Anticosti, Pelee and Prince Edward admiring beautiful landscapes along the way. Fair winds.
Race #1910
INFO from brainaid.de
Melges 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ2 - ARCH - SUPSOL – SYC
Race starts: Apr 21st 17:00 Registration Open!
▶ 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 Open!
▶ Flash
GO TO RACE

Gladstone Ports Corporation Brisbane to Gladstone Yacht Race 2025


Sailonline is thrilled to partner with the Queensland Cruising Yacht Club for the 2025 Gladstone Ports Corporation Brisbane to Gladstone Yacht Race. This 308 nautical mile offshore classic takes our fleet from Brisbane to Gladstone along Australia's stunning east coast. Racing in high-performance Cookson 50s, SOLers will face shifting winds and tactical decisions at every turn. It’s time to test your skills in one of Australia’s most iconic yacht races. See you on the start line!
Race #1904
INFO by brainaid.de
Cookson 50 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
RACE CLOSE: Wednesday,
April 23 at 2300 UTC.
Race starts: Apr 18th 01:00 Registration Open!
▶ Flash
GO TO RACE

Bahamas and Back TIMED Race 2025

Welcome to sunny South Florida for this race that has us crossing the Gulf Stream twice. We depart from Palm Beach for a short run over to Freeport, Bahamas then it’s on to Miami before heading to the finish line back in Palm Beach. 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 #1911
INFO by brainaid.de
Santa Cruz 70 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ2 - TRCH - SUPSOL - SYC
RACE CLOSE: Saturday,
26 April at 23:00 UTC
Race starts: Apr 13th 12:00 Registration Open!
▶ 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 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

Melbourne Osaka Cup Double-Handed Yacht Race 2025

Welcome once again to what these days is Sailonline’s almost annual virtual Melbourne to Osaka Yacht Race. In real life, this double-handed 5500 nm race between these two sister cities, one deep in the southern hemisphere, the other high in the northern hemisphere, is run every four to five years, and this year is such a year. So, this year’s online version is in sync with the Melbourne Osaka Cup 2025 organised by the Ocean Racing Club of Victoria (ORCV), and the Sandringham (SYC) and Osaka Hokko (OHYC) yacht clubs. We’ll be racing the well-known First 40, a popular size of boat which should be a good match for many of the boats entered in the real race. With the doldrums unavoidably lying across our course, you can expect to be at virtual sea for at least a month!
Race #1669
INFO by brainaid.de
First 40 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
RACE CLOSE: Wednesday,
April 23 at 2300 UTC.
Race starts: Mar 16th 06:00 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 KaSToR
  4. Sailonline Yacht Club Member CriticalHippo
  5. Sailonline Yacht Club Member vida
  6. Sailonline Yacht Club Member FreyjaUSA
  7. Sailonline Yacht Club Member rafa
  8. Sailonline Yacht Club Member Kipper1258
  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