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: First Previous 7 8 9 10 11 12 13 Next

Posted by
dtayls


Users avatar

Posts
30
Registered at
2014-06-23 03:34:16
2014-11-19 01:38:23 - Re: Performance loss
There are some really interesting ideas in the pipeline and there is a great team of people working on it. Physical (kinetic) performance loss certainly exists but it's probably not a significant issue in an ocean race. Crew fatigue, on the other hand, is probably much more important. Lots of manoevres (tacks/gybes) will take a big toll on the crew. And doing these in high winds or at night is going to have an even greater impact. So, perhaps double at night; a sliding scale from x1 to x5 from 20 to 50 kts; and a no-go-zone from 50kts+ where you can't tack or gybe at all because the crew is simply refusing to get up on deck.

--- Last Edited by dtayls at 2014-11-19 01:56:30 ---
Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2014-11-22 18:02:52 - Re: Performance loss
I do like the last bit--"the crew is simply refusing to get up on deck."--0r in our case "get out of bed".
Obviously we need much more versatile DC nomenclature......
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
RCLASER27


Users avatar

Posts
2
Registered at
2015-06-06 11:16:15
2015-08-10 18:25:55 - Re: Performance loss-Eureka!!!! ????
It seems to me that the subject of Performance Loss has the highest number of posts with the most controversy and many are still unclear as to how it works and whether it is fair. It is also clear to me that for those that are 'clever' there is an opportunity to 'cheat'.
I know you are trying to design a realistic sailing simulator but surely the Performance Losses for an AC72 (foiling cat) are considerably different from a monohull.
My point is why have it at all? What 'harm' would that cause to your drive for 'realism'? If indeed you need a 'penalty' why not apply a standard one across the board of 50% boat speed reduction for 2 minutes. This would stop the short tacking zigger-zaggers. This would only apply to tacks not gybes. Of course a penalty such as that is totally unrealistic in the sailing world but at least everyone would understand it rather than having something that is almost subjective and seems to vary at random and cannot easily be understood. I await your comments.
Posted by
kroppyer


Users avatar

Posts
347
Registered at
2010-02-05 15:25:55
2015-08-10 19:23:50 - Re: Performance loss
Simple solutions like this have crossed our minds. I reject some of them because they do not satisfy a couple of requirements. For example, I'd like to have two consecutive manoeuvres twa 45 -> 50 -> 55, to result in a distance loss that is no less than the loss resulting from a single manoeuvre twa 45 -> 55. At the least both losses need to be comparable. So we can't really penalise a manoeuvre regardless of the change in angle.

Of course the easiest way to get a minimum of realism into the performance loss model would be to handle a change of tack differently.

Another, more important, requirement is that every manoeuvre that crosses a cavity in the polar (polar hopping, including tacking/gybing), needs to be penalised by a significant amount. This is to prevent "infinite" manoeuvring (tacking/gybing/hopping) along a shoreline or lane of high pressure.

Your suggestion of penalising only tacks a̶n̶d̶ ̶g̶y̶b̶e̶s̶ does not satisfy this requirement.

These requirements are not really worked out or well discussed. I welcome any critique or additions on them.

I do fully agree with your idea of having a model that anyone understands. It makes the game more fair when everyone understands the rules. So we need a model that is either simple (easy to understand), or very realistic (sailors will quickly understand). Of course the second option is much harder to realise, but also a lot more rewarding.

--- Last Edited by kroppyer at 2015-08-10 20:00:27 ---
Posted by
RCLASER27


Users avatar

Posts
2
Registered at
2015-06-06 11:16:15
2015-08-10 19:55:03 - Re: Performance loss
Just to clarify my earlier post there is NO penalty for gybing, only Tacking
Posted by
JB


Users avatar

Posts
305
Registered at
2013-03-07 08:54:34
2015-08-26 11:52:04 - Re: Performance loss
Viva All.

Recap on this:

1 - One of SOL goals is to approach as much as possible the real boats behaviour.

2 - This one is pacific - gybing a “barge” is not the same as gybing a foiling boat.

3 - A real example: an AC72 don’t lose Performance during foiling gybes and doesn’t take more than 30 minutes to recover from any maneuver made (tack or gybe).

4 - So, “zero” Loss of Performance (LP) as a rule for all boats during/after gybing doesn’t seem to me correct.

5 - LP should be, namely, boat dependent and not only on the BS/TWA couple previously obtained to the boat maneuvers (small/large turning or making a full tack/gybe).

6 - More important than the LP value (boat dependent, namely, or not) is the Recovering Time to reach again the 100% P;

7 - Exception made to slower boats (barge, fixed keel 30 ft cruisers, not racers) and for all boats in special “blue” conditions (TWS / BS < 5 - 6 Kts) the SOL LP is almost irrelevant.

8 - The big problem comes on the remaining boats/Wind conditions, being the AC72 the extreme paradigm of this issue.
Sail Fair.
Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2015-10-27 01:35:30 - Re: Performance loss
I hate to butt into a tech argument that I have contributed to in the past--to a level that is long past my pay-grade!! -----but surely some programmer for one of the many other sailing sites has solved this problem some time ago---and might be invited/paid to do a little modification to OUR perf loss problem??????
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
bonknhoot


Users avatar

Posts
111
Registered at
2013-08-06 21:35:15
2016-05-06 16:01:13 - Re: Performance loss
As long as we can't change it, best we live with it on an equal footing. This might have seen the light of day when we went ice yachting on Winnebago, but then we switched PL off altogether (another solution!).
I am not guaranteeing anything written in the attached is the best way of "evading" usurious PL, just stuff that works for me (if I get it right).
Clipping along
Attachments
Posted by
Capt.D.P.


Users avatar

Posts
66
Registered at
2009-10-27 01:51:32
2016-11-24 14:04:40 - Re: Performance loss
I went little bit through this topic and to tell you the truth I did not know about 93% rule in loss performance.Years ago maybe 7-8, I spent a lot of time to find out how to reduce that annoying performance loss.I surely went through that 93% but did not notice big difference but noticed that performance could be down even to 82%,when gybing with big speed
several times in fast continuation.

We all know that smaller the change of course less performance loss but there is an exception in that rule.
There is a situation when you change the course for 1 degree only and you have performance loss of 90%.I found it while trying to gyb step by step and coming to 179.5 deg. and to -179.5 deg. and at once performance loss for one degree which use to be only cca 99.8% jumped down to 90%.

As the perf. loss is minor when tacking I even tried that to go in desired direction but found out that more ground is lost than the gain in performance loss.

Ciao
Damir
Posted by
kroppyer


Users avatar

Posts
347
Registered at
2010-02-05 15:25:55
2016-11-24 16:00:39 - Re: Performance loss
Yes, when you change tack, the degrees you turn is irrelevant, but the new boatspeed is relevant. So when turning from 179.5 to -179.5 you will be penalised proportional to your new boatspeed. When going upwind, you generally have less boatspeed, so changing tack is less costly.

See a complete breakdown of performance loss here.

This is bound to change at some point though (not sure when, could be years, but I'm hoping less).

Page: First Previous 7 8 9 10 11 12 13 Next

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Roma Giraglia Regata 2026

Our eighth race of nine to celebrate all things Mediterranean - fickle winds, history and olive oil – is another buddy-up; this one with the Circolo Nautico Riva di Traiano . Founded in 1984, as the new Traiano yacht Harbour neared completion, the Circola since then has developed into one of the major yachting competition centres in Italy, and next to the 450nm Roma per Tutti (which SOL buddied earlier in the year), the Roma Giraglia Regata is its other headline offshore event. First raced in 2005, the 210nm course takes competitors from Traiano to a rock on the inside of the Ile de la Giraglia off the northern tip of Corsica and back to the Italian mainland for a finish in the bay of Santo Stefano. We’re racing this one in our Class 40!
Race #2058
INFO by brainaid.de
Class 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: MED - SUPBUD - SYC
Race starts: Oct 08th 16:00 Registration Open!

▶ Flash
GO TO RACE

Arctic Tern - Greenland to Antarctica 2025

Welcome to the fifth leg of our MIG series. Now it's time to race the Arctic Terns, on their migration from Greenland to Antarctica, 8300 NM. This is also part of our monthly Ocean Championship, and as such the first race of OCQ4 2026. This race will be sailed in our Maxi Trimaran. Race #2061
INFO by brainaid.de
Maxi Trimaran PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230 Ranking:
OCQ4 - OCCH - SYC - MIG
Race starts: Oct 05th 11:00 Registration Open!
▶ Flash
GO TO RACE

Bornholm PYOC


Welcome to the Baltic Sea, where we are about to hold another sprint race. The course runs from the north to the south of the beautiful Bornholm island. There are only two waypoints, the start and the finish so the choice of which side of the island to sail along is up to you. Our Albin 79s will cover a distance of approximately 23 nautical miles.
Race #2064
INFO by brainaid.de
Albin 79 PARTICULARS
WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SPQ4 - SPCH - SYC
Race starts: Oct 03rd 06:00 Registration Open!
▶ Flash
GO TO RACE

Cross the Convergence 2026 - Masirah to Chagos


Having crossed, re-crossed and re-re-crossed the Convergence Zones of the Pacific and the Atlantic, we now face our second crossing of the Convergence Zone of the World’s third great equator-spanning sea, the Indian Ocean, taking us from the channel between Masirah Island and the Oman mainland to the Chagos Archipelago. It’s 1900nm and we’ll be sailing our very fine Archer 78, and won’t mention that both locations (of departure and arrival) are heavily militarized and the why’s and what next’s concerning that – mindful as always of SOL Netiquette.
Race #1988
INFOby brainaid.de
Archer 78PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: CCZ - SYC
Race starts: Oct 02nd 18:00 Registration Open!
▶ Flash
GO TO RACE

Carib Rum Run 2026


Ahoy, ye landlubbers and seasoned salts! Welcome back to Sailonline’s legendary Carib Rum Run, perfectly timed to kick off on International Talk Like a Pirate Day, 19 September!

This year, we command the magnificent Falkun—the ultimate high-tech superyacht modeled after the iconic Maltese Falcon. This 1759nm slalom takes us through the Caribbean’s rum islands to plunder barrels from local distilleries and deliver them to the rum-parched sands of Cancun.

Join SYC before the finish to disguise yer boat with a pirate name for this race only. Hoist the sails, sharpen yer cutlasses, and plot your winning course!
Race #2060
INFO by brainaid.de
Falkun PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: Sep 19th 05:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member KaSToR
  2. Sailonline Yacht Club Member CriticalHippo
  3. Sailonline Yacht Club Member WRmirekd
  4. Sailonline Yacht Club Member rafa
  5. Sailonline Yacht Club Member Panpyc
  6. Sailonline Yacht Club Member cdhinman
  7. Sailonline Yacht Club Member rumskib
  8. Sailonline Yacht Club Member rthinman
  9. Sailonline Yacht Club Member BRENTGRAY
  10. Sailonline Yacht Club Member Sax747

View full list

Series

Mobile Client

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

The mobile client