Login
Support Sailonline
If you haven't already - join the SAILONLINE YACHT CLUB!
Please also consider making a donation - all amounts are greatly appreciated!
Posted by hmm |
|
Post annotated by
RainbowChaser
:
This thread was moved from the category General Discussion. I think most of this is quite general knowledge by the more active solers but to clarify things, I want this to be general knowledge:
1. Performance loss percentage when tacking/gybing is half of your boat speed after the tack/gybe. I.e. if you gybe to an angle where the boatspeed would be 20kts, the perf loss would be 10% and boat performance will be 90%. 2. When not changing tacks, the performance loss is much less and depends on the amount of turn + the boat speed after the turn. 3. The performance loss is cumulative, however if your performance is less than 93% the additional turns or tacks will not cause more loss. 4. The performance gain is logarithmical, i.e. gain from 90->91 is much faster than 99->100. In my opinion, as this facts have been mentioned many times in chats, so they are sort of general knowledge. They probably should be in the manual as well. And, during my latest run in Kerguelen Timed race, knowing rules 1. and 3. during my gybe near Cap Digby was important. |
|
Posted by Go4iT |
|
If I understand you correctly, you gybed to a square run (minimising Boat Speed after the gybe) so as to reduce your performance loss (Rule 1). With the performance loss then >93% you hardened up to optimum negative VMG without incurring any additional penalty (rule 3).
I am lucky to be within a minute of you as I slammed my boat into the gybe with a penalty I carried most of the way down the East Coast of the island. Thanks for the education. --- Last Edited by Go4iT at 2013-10-12 07:12:16 --- |
|
Posted by Rod |
|
In view of some comments on the chat regarding this discussion of the Perf Loss problem, I would like to clarify my position. I did not know about the "93% Rule" before now, although I have both inquired and commented upon the problem several times over the last 2-3 yrs.
'hmm' obviously did know, as he has stated it here. But I do ask--"How did he know?" ---unless he had read the code or been told by someone who HAD read the programming code. How many others had such private knowledge? I know that I 'sail' here as precisely as I can, yet find others achieving speeds of which I seem incapable. Yours, for a level playing field, Rod. If it breaks, it's not strong enough--if it doesn't, it's too heavy. |
|
Posted by RainbowChaser |
|
Rod - most people find things out by practising themselves and testing the polars to see how they perform. The person who taught me to do this, NZL Spindrift, isn't often SOLing these days but he would spend ages in pre-race practice to-ing and froing and working it out. He also taught me the concept of "averaging" when calculating DCs.
Sadly, most of the hints/tips I have acquired I have forgotten through lack of use as I now spend all my time doing Admin type stuff. Aaron, for example, made copious notes on each race - that is why his "new" GUI has a notes function associated with it. A lot of finding out about SOL isn't stuff that anyone is acquiring secretly, most of it is in plain sight and, you are right, it would be great to have tips/hints all listed.... maybe you would do this.. act as a scribe here for any/all the hints/tips you have acquired through being on SOL and asking questions? As for the perf loss "thing"? I didn't know it either and, if I hadn't arrived in chat when I did, I still wouldn't!! That's why I would like to see info shared in the Forums... PLUS I'd also really like folks to read the Manual... there's a LOT of information there and most think "I know how to SOL I don't need to read it"... <eyeroll> |
|
Posted by Rod |
|
I had never heard of "averaging" as any part of setting DCs. My DC setting experience has suggested:-
1. Never trust the next Wx---set your alarm clock and get out of bed. 2. Never set a DC that that includes a tight turn around a headland---you will always turn short, and spend several hours on the rocks, until you obey point (1.) above... 3. Never trust a TWA course beyond the Wx change time--again, get out of bed. 4.Get yourself a kitchen timer and set it a minute or so BEFORE anything is supposed to happen, and be there to supervise. 5. No matter how long the race is, sit constantly in front of your computer and adjust your course every few minutes--when you do, you will ALWAYS find that you are going slightly slower than you could be, and are therefore LOSING. 6. Sleep, Work, Meals, Errands, medical emergencies, etc.etc. are not conducive to fast SOLing, so don't do them...... If it breaks, it's not strong enough--if it doesn't, it's too heavy. |
|
Posted by RainbowChaser |
|
I'll try and find my handwritten notes that I made back in 2009 when Spindrift told me how to calculate reasonable "longhand" DCs.
Gist is using the wx slider, take readings of wind speed and direction over DC-able period.. then average them, from this you will derive likely BS and on time/distance you can set reasonable DCs. But you are probably doing that already? I just sail my own boat here on SOL... probably because I don't have time to look at what others are doing. If someone makes a massive leap in performance or results, i am interested to learn why/how it might be, but otherwise accept that if I only change course a few times a day and miss wx updates then I get the results I deserve. But I also accept that while bright in my own way, I don't have a lifetime of sailing experience, I don't have time to spend even working out best-average DCs, I am probably not as smart as many sailing here, esp the top performers, so I don't expect to sail as well as any one particular other person. As an individual I am competitive, have always been, so it is quite galling to perform so badly, but set in context of my health, my SOL Admin current workload and the complete lack of spare "brain", I just have to accept my results are mediocre at best. One day, when the new organisation is in place, and I have little in teh way of workload, I may have to accept that my results are because I am not that good!! hehehe Until then, I am wishfully thinking that they will and can improve BUT you didn't say anything about being our scribe for tips/hints? picking up ideas where you see them in chat etc? What say you? _____________ --- Last Edited by RainbowChaser at 2013-10-10 19:50:07 --- |
|
Posted by hmm |
|
Rod, my point on this posting is to share knowledge so that SOL would be a level playing field. I could have of course just chosen to be silent but I happen to believe in fair game.
I obviously have access to the code but to learn about the 93% rule you don't need to have access to it. You just have to turn your boat when having less than 93% performance to notice that the performance won't drop any further. I believe many people knew at least that there is a limit of more loss near 90% so I found it fair to share the information here to everyone. |
|
Posted by Rod |
|
I fully accept your explanation, and had no intention of accusing anyone of 'intentional unfairness'.
It is a fact that I had never heard of 93%, and do not think that any normal experimentation would have derived that situation. I did experiment with 'stepping' around a turn in small increments, but found that the perf loss was, as expected, cumulative. I once tried running down the English Channel while staying in the center where the wind speed was greatest, and the perf loss caused me to lose ground steadily. In radio sailing, we all know that "tacking is slow", (our small boats do not have much momentum), but gybing is quick and results in only small loss of speed. It would have required a rather sophisticated research program to test tacks and gybes in two 'steps' of varying angles to derive the 93% rule. This would, I think, be something more than the average SOLer would think to set up himself---unless he suspected that such a phenomenon existed. I think you will agree that there is nothing obvious in sail boat performance that would even suggest that a 'two-step' tack or gybe should be faster overall than any 'single step' turn. If it breaks, it's not strong enough--if it doesn't, it's too heavy. |
|
Posted by K3 (Bernd) |
|
I have no access to the code and it would be useless for me if I have
The limit of performance loss is easily to see, when you ping-pong narrow channels by DCs. You will stay near 93% all the time and you will be 7%+bbq-time behind the leaders at the finish. I want a performance loss limit for my IRL-boat and for my personal human performance loss too Ciao Bernd (K3) |
|
Posted by kroppyer |
|
It's doable to find these rules just by trying, however it's a huge help to have a little head start like this.
I always thought performance loss depends on the boat-type, and possibly on the wind speed. But the boat-type doesn't matter, and it's not windspeed, but boatspeed that determines performance loss. It would've taken a long time to figure that out. I think I would've found the 93% rule if I was trying to figure out how performance worked. I've noted before that, when I was tacking and gybing once or twice a minute, performance was always 92%/93% or a little lower. It never got as far down as I expected. I want to put performance loss and recovery into spinnacer, and maybe there's gonna be more I will be putting into this program. As I'm doing that, I'm trying to find the exact formulas SOL uses. I have no problem sharing these formulas, so following RC ("it would be great to have tips/hints all listed"), should I prepare to make a list of these formulas? With possible ways to use/misuse them? Should I aim to describe them so that everyone understands, or so that they're exact, correct and unambiguous? Be aware, admins, I've heard you don't want the entire working of SOL open for public? Then at what point should I stop publishing the formulas behind SOL? (RC/hmm, this might overlap with the mail I will send you) Anyway, thanks for sharing this hmm! EDIT, after reading k3's post, I wondered, what exactly happens with performance if beached (how much does it drop)? It's easy to find out, but easier if someone just tells it. --- Last Edited by kroppyer at 2013-10-10 22:48:59 --- |
Races
Next Race: 00d 00h 00m
Current Races:
Kapiti Chetwodes Race 2024
For only the second time in SOL history, we have the pleasure of inviting you to the Kapiti Chetwodes Race, held in the Cook Strait region. Organised IRL by the Royal Port Nicholson Yacht Club from Wellington in New Zealand. The approximately 160nm long route, full of turning points, will take us from the bay at RPNYC around the islands of Somes, Kapiti and Chetwodes and back to the finish line at RPNYC. We have only a 26 ft Albin 79 yacht at our disposal. All this means that we will have a lot of fun, so fair winds!
Race #1864
INFO by brainaid.de
Albin 79 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ4 - ARCH - SUPSOL - SYC
Race starts: Nov 25th 17:00 Registration Open!
GO TO RACE
Raja Muda Selangor 2024 - Penang to Langkawi
Welcome to the third and last online race of the Raja Muda Selangor International offshore series – a 70nm final trip further north again up the Malacca Strait from Penang to the exotic island of Langkawi, and again in Ker 40s.
Race #1871
INFO by brainaid.de
Ker 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RMS - SYC
RACE CLOSE: Monday,
November 25 at 2300 UTC.
Race starts: Nov 21st 04:00
Registration Open!
Raja Muda Selangor 2024 - Pangkor to Penang
Welcome to our second online offshore race in cooperation with Raja Muda Selangor International – an 80nm trip from Pangkor north to Penang up the Malacca Strait, again in Ker 40s.
Race #1870
INFO by brainaid.de
Ker 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RMS - SYC
RACE CLOSE: Saturday,
November 23 at 2300 UTC.
Race starts: Nov 18th 04:00
Registration Open!
Two Oceans Doublecross TIMED Race 2024
Race #1872
INFO by brainaid.de
Archer 78 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ4 - TRCH - SUPSOL - SYC
RACE CLOSE: Saturday,
30 November at 23:00 UTC
Race starts: Nov 17th 12:00 Registration Open!
GO TO RACE
Nassau to Bodo 2024
PRIZE: SMPF
Race# 1866
INFO from brainaid.de
Swan 65 PARTICULARS
WX updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ4 - OCCH - RTW - SUPSOL - SYC
Race starts: Nov 11th 11:00 Registration Closed
GO TO RACE
SYC Ranking
Series
- SYC ranking
- 2024 TS
- 2024 TRQ4
- 2024 TRQ3
- 2024 TRQ2
- 2024 TRQ1
- 2024 TRCH
- 2024 TD
- 2024 SVF
- 2024 SUPerSOLer
- 2024 SSANZ
- 2024 SPRQ4
- 2024 SPRQ3
- 2024 SPRQ2
- 2024 SPRQ1
- 2024 SPRCH
- 2024 SHE
- 2024 RTW
- 2024 RMS
- 2024 PIC
- 2024 OCQ4
- 2024 OCQ3
- 2024 OCQ2
- 2024 OCQ1
- 2024 OCCH
- 2024 LOOR
- 2024 HILAT
- 2024 GWT
- 2024 DN
- 2024 CRW
- 2024 B2B
- 2024 ARQ4
- 2024 ARQ3
- 2024 ARQ2
- 2024 ARQ1
- 2024 ARCH
- 2023 TS
- 2023 TRQ4
- 2023 TRQ3
- 2023 TRQ2
- 2023 TRQ1
- 2023 TRCH
- 2023 TD
- 2023 SVS
- 2023 SUPerSOLer
- 2023 SSANZ
- 2023 SPRQ4
- 2023 SPRQ3
- 2023 SPRQ2
- 2023 SPRQ1
- 2023 SPRCH
- 2023 SHE
- 2023 RTW
- 2023 RNI
- 2023 RMS
- 2023 PIC
- 2023 OCQ4
- 2023 OCQ3
- 2023 OCQ2
- 2023 OCQ1
- 2023 OCCH
- 2023 LOOR
- 2023 DN
- 2023 ARQ4
- 2023 ARQ3
- 2023 ARQ2
- 2023 ARQ1
- 2023 ARCH
- 2022 TRQ4
- 2022 TRQ3
- 2022 TRQ2
- 2022 TRQ1
- 2022 TRCH
- 2022 TD
- 2022 Tall Ships
- 2022 SUPerSOLer
- 2022 SSANZ
- 2022 SSA
- 2022 SPRQ4
- 2022 SPRQ3
- 2022 SPRQ2
- 2022 SPRQ1
- 2022 SPRCH
- 2022 SHE
- 2022 OCQ4
- 2022 OCQ3
- 2022 OCQ2
- 2022 OCQ1
- 2022 OCCH
- 2022 NTR
- 2022 LOOR
- 2022 CTR
- 2022 ARQ4
- 2022 ARQ3
- 2022 ARQ2
- 2022 ARQ1
- 2022 ARCH
- 2021 TRQ4
- 2021 TRQ3
- 2021 TRQ2
- 2021 TRQ1
- 2021 TRCH
- 2021 TD
- 2021 Tall Ships
- 2021 SYCQ4
- 2021 SYCQ3
- 2021 SYCQ2
- 2021 SYCQ1
- 2021 SYCCH
- 2021 SUPerSOLer
- 2021 SSANZ
- 2021 SPRQ4
- 2021 SPRQ3
- 2021 SPRQ2
- 2021 SPRQ1
- 2021 SPRCH
- 2021 Shetland
- 2021 PAC6
- 2021 OCQ4
- 2021 OCQ3
- 2021 OCQ2
- 2021 OCQ1
- 2021 OCCH
- 2021 ESRW
- 2020 TSE
- 2020 TSA
- 2020 TRQ4
- 2020 TRQ4
- 2020 TRQ3
- 2020 TRQ2
- 2020 TRQ1
- 2020 TRCH
- 2020 Tasman Double
- 2020 SYCQ4
- 2020 SYCQ3
- 2020 SYCQ2
- 2020 SYCQ1
- 2020 SYCCH
- 2020 SUPerSOLer
- 2020 SSANZ
- 2020 SRQ4
- 2020 SRQ3
- 2020 SRQ2
- 2020 SRQ1
- 2020 SPRCH
- 2020 Shetland
- 2020 RTW
- 2020 RNI
- 2020 Odyssey
- 2020 OCQ4
- 2020 OCQ3
- 2020 OCQ2
- 2020 OCQ1
- 2020 OCCH
- 2020 A3
- 2019 TRQ4
- 2019 TRQ3
- 2019 TRQ2
- 2019 TRQ1
- 2019 TRCH
- 2019 Tasman Double
- 2019 Tall Ships
- 2019 SYCQ4
- 2019 SYCQ3
- 2019 SYCQ2
- 2019 SYCQ1
- 2019 SYCCH
- 2019 SUPerSOLer
- 2019 SSANZ
- 2019 SRQ4
- 2019 SRQ3
- 2019 SRQ2
- 2019 SRQ1
- 2019 SPRCH
- 2019 Shetland
- 2019 Round New Zealand
- 2019 OCQ4
- 2019 OCQ3
- 2019 OCQ2
- 2019 OCQ1
- 2019 OCCH
- 2018 TRQ4
- 2018 TRQ3
- 2018 TRQ2
- 2018 TRQ1
- 2018 TRCH
- 2018 Tasman Double
- 2018 Tall Ships
- 2018 SUPSOL
- 2018 SSANZ Triple
- 2018 SRQ4
- 2018 SRQ3
- 2018 SRQ2
- 2018 SRQ1
- 2018 SPRCH
- 2018 Shetland
- 2018 Shackleton Challenge
- 2018 OCQ4
- 2018 OCQ3
- 2018 OCQ2
- 2018 OCQ1
- 2018 OCCH
- 2018 40CH
- 2017 TS RDV
- 2017 TRQ4
- 2017 TRQ3
- 2017 TRQ2
- 2017 TRQ1
- 2017 TRCH
- 2017 Tasman Double
- 2017 Tall Ships
- 2017 SWR
- 2017 SUPSOL
- 2017 SSANZ Triple
- 2017 SSANZ RNI
- 2017 SPRR3
- 2017 SPRR2
- 2017 SPRR1
- 2017 SPRCH
- 2017 Red Dot
- 2017 OCQ4
- 2017 OCQ3
- 2017 OCQ2
- 2017 OCQ1
- 2017 OCCH
- 2017 40CQ3&4
- 2017 40CQ1&2
- 2016 TRQ4
- 2016 TRQ3
- 2016 TRQ2
- 2016 TRQ1
- 2016 TRCH
- 2016 Tasman Double
- 2016 Tall Ships
- 2016 SUPSOL
- 2016 SSANZ Triple
- 2016 SRQ4
- 2016 SRQ3
- 2016 SRQ2
- 2016 SRQ1
- 2016 SPRCH
- 2016 RTWR
- 2016 OCQ4
- 2016 OCQ3
- 2016 OCQ2
- 2016 OCQ1
- 2016 OCCH
- 2016 Corporate Open Gold
- 2016 A3
- 2015 TRQ4
- 2015 TRQ3
- 2015 TRQ2
- 2015 TRQ1
- 2015 TRCH
- 2015 Tasman Double
- 2015 Tall Ships
- 2015 SYQ4
- 2015 SYQ3
- 2015 SYQ2
- 2015 SYQ1
- 2015 SYCCH
- 2015 SUPSOL
- 2015 SSANZ Triple
- 2015 SRQ4
- 2015 SRQ3
- 2015 SRQ2
- 2015 SRQ1
- 2015 SPRCH
- 2015 OCQ4
- 2015 OCQ3
- 2015 OCQ2
- 2015 OCQ1
- 2015 OCCH
- 2015 Aegean Rally
- 2014 Timed Races Championship
- 2014 Tasman Double
- 2014 Tall Ships
- 2014 SYC Championship
- 2014 SSANZ Trio
- 2014 SSANZ RNI
- 2014 Sprints Championship
- 2014 Scandinavian Tour
- 2014 Round The World Race
- 2014 Ocean Championship
- 2014-2015 Sailonline World Race
- 2013 Tall Ships
- 2013 SYC Championship
- 2013 SSANZ B&G Simrad
- 2013 Capt Anderson
- 2012 W Australia Regatta
- 2012 Tall Ships
- 2012 SSANZ B&G Simrad
- 2012 RNZ Two Handed
- 2012 Global Challenge
- 2012 Ecker Cup
- 2012 Black Sea
- 2012 A3
- 2011 Vancouver Island
- 2011 Tasman Double
- 2011 SSANZ B&G Simrad
- 2011 SOL Global Challenge
- 2011 SJORA Series
- 2011 Scandinavian Tour
- 2011 Round North Island
- 2011 Asian Sprints
- 2011-2012 SOL World Race
- 2010 Tasman Double
- 2010 Ouzo Rally
- 2010 Iberian Tour
- 2010 Auckland Regional
- 2009 French SOLo
- 2009 Bosphore - Bretagne
- 2008 SYCC
- 2008 -2013 SYC Week Race Championship
- 2008 -2013 SYC Week-End Race Championship
- 2008 -2013 SYC Ocean Race Championship
- 2008-2009 Sailonline Ocean Race
- 2004 LOOR
Mobile Client
SYC members have the benefit of access to our mobile/lightweight web client!