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Re: Rating rant [Re: Todd_Sails] #165583
01/21/09 02:03 PM
01/21/09 02:03 PM
Joined: Jun 2001
Posts: 3,906
Clermont, FL, USA
David Ingram Offline
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Todd, you want the numbers done right volunteer to crunch the numbers. It's been my experience the OA will happily hand off this task.



David Ingram
F18 USA 242
http://www.solarwind.solar

"Do or do not. There is no try." - Yoda
"Excuses are the tools of the weak and incompetent" - Two sista's I overheard in the hall
"You don't have to be a brain surgeon to be a complete idiot, but it helps"
-- Have You Seen This? --
Re: Rating rant [Re: David Ingram] #165586
01/21/09 02:12 PM
01/21/09 02:12 PM
Joined: Feb 2006
Posts: 3,348
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fin. Offline
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whistle

Re: Rating rant [Re: David Ingram] #165599
01/21/09 03:27 PM
01/21/09 03:27 PM
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Posts: 12,310
South Carolina
Jake Offline
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Originally Posted by David Ingram
For the record the Area D South data I can get my hands on is given to Darline in SailWave format with wind corrector mods used.


As have ours too. This is conjecture - but I suspect that most of the results that the Portsmouth Committee receives from multihulls come from the Alter Cup Qualifiers since they have to submit them and they have to use the wind correction factors.


Jake Kohl
Re: Rating rant [Re: TeamChums] #165602
01/21/09 03:41 PM
01/21/09 03:41 PM

S
Scarecrow
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S



Originally Posted by TeamChums

If your area rep is on an F18 and the gripe is the difference in the numbers between F18's and N20's, do you think it would allways be effective to let them know? Not complaining about our rep, but wtf? The F18 sail plan has evolved quite a bit while the N20 is gathering dust for the past 7 years and the numbers don't seem to reflect this.


I think you'll find none of the evolution of F18 sails would result in a change to the SCHRS rating, as I believe its already based upone the extremes of the box rule. So you more likely to get an adjustment under PY than under a measurement system.

Re: Rating rant [Re: Todd_Sails] #165607
01/21/09 03:56 PM
01/21/09 03:56 PM
Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Mark Schneider Offline
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Mark Schneider  Offline
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Todd

the fact that the RC did not use wind adjusted numbers to determine your finish position is irrelevant to calculating the rating for the boat.

All that was needed was for them to turn in the elapsed times and the wind speed for each race. They don't even care about the second boat in the class finish time.

TikPete... its called a yardstick for a reason.

The Primary yardstick is a thistle. the rating will never ever change for a thistle... its the standard which all other boats are compared with. Other boats are designated as secondary yardsticks .... their ratings change very very slowly.

If a rating is not changing... then the boat is being optimally sailed relative to the yardsticks.

Or... the actual speed improvement can not be measured with the amount and quality of the data collected.

the Mid atlantic region could only turn in two or three regattas worth of weekend buoys race data in 2008 because most of the racing is now one design and times were not recorded.

Jake's proposal that statistics will fine tune a measurement rating is merely a dream because the amount of data needed is just not out there to resolve small performance differences.

Even if the new Hobie F18 is a bit faster... Handicap racing will never measure the speed improvement due to the noise of boat racing against a Nacra 20 or a Blade F16.

He presumes that the measurement rating table is not accurate and requires some fine tuning with statisitcs.
To support this notion, he should at least identify boats in the measurement ratings that need some fine tuning with the performance data relative to each other. The sailors who use Texel or SCHRS are not out their complaining.

My view, is that the rating systems are about as accurate as you are likely to get. The differences are how they deal with changes and new designs in time. Measurement rules have a clear advantage.

There is a reason the ratings don't use several decimal places in the tables.

Most of the big boat ratings experts don't think you will be able to do better then 2.5%.... simply based on the nature of racing and the time of the race. Eg... if you don't get a lane on the first beat... you are slotted to a poor rounding round A mark... no matter how fast you are you can't use it on the first 1/4 of the race .... and the clock keeps on ticking.

It's a lot easier to get the data on a boat class measurments once then continually collect race results. If you get creative and change your sail ... then pay the 20 bucks and get it independently measured for your personal rating certificate.

The latest design by Ashy may be faster... but won't be measured using Portsmouth ratings of different class boats.

Last edited by Mark Schneider; 01/21/09 04:13 PM.

crac.sailregattas.com
Re: Rating rant [Re: Mark Schneider] #165610
01/21/09 04:07 PM
01/21/09 04:07 PM
Joined: Feb 2006
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fin. Offline
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"the actual speed improvement can not be measured with the amount and quality of the data collected."

I suspect this is the case.

"Other boats are designated as secondary yardsticks .... their ratings change very very slowly." I'd like to know more about that if you have the time.

Thanks.


Re: Rating rant [Re: fin.] #165612
01/21/09 04:21 PM
01/21/09 04:21 PM
Joined: Jul 2001
Posts: 2,844
42.904444 N; 88.008586 W
Todd_Sails Offline
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As I saild, it usually works pretty well, and I wasn't complaining.

I never blamed the numbers when I raced in portsmouth class. You have to have some kind of handicapping system, this one works well. Nothing is perfect, not even the perfect stranger.- Crissy Hines (spelling?)


F-18 Infusion
#626- SOLD it!

'Long Live the Legend of Chris Kyle'
Re: Rating rant [Re: Todd_Sails] #165613
01/21/09 04:24 PM
01/21/09 04:24 PM
Joined: Jul 2001
Posts: 2,844
42.904444 N; 88.008586 W
Todd_Sails Offline
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'All that was needed was for them to turn in the elapsed times and the wind speed for each race. They don't even care about the second boat in the class finish time.'

My point was that, using different numbers at different wind speeds on different boats, could affect the portsmouth outcome, in a very close race.

For now, my vote, (as if I had one), is to stay with this measurement system.


F-18 Infusion
#626- SOLD it!

'Long Live the Legend of Chris Kyle'
Re: Rating rant [Re: Todd_Sails] #165625
01/21/09 04:54 PM
01/21/09 04:54 PM
Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Mark Schneider Offline
Carpal Tunnel
Mark Schneider  Offline
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Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Sorry, did not understand your point.

Yes, The windspeed ratings do a better job then a single number and the final result could change if they were used.

USPN is statisitical and not measurement based.

The issue is moving forward for the next 5 or 10 years... Would a measurement rule serve the USA better then a statistical rule. Times are taken for both systems and the PN System would not be starved for data and still could be used for clubs who did not want to switch.


crac.sailregattas.com
Re: Rating rant [Re: Mark Schneider] #165630
01/21/09 05:10 PM
01/21/09 05:10 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
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South Carolina
Originally Posted by Mark Schneider
Todd

the fact that the RC did not use wind adjusted numbers to determine your finish position is irrelevant to calculating the rating for the boat.

All that was needed was for them to turn in the elapsed times and the wind speed for each race. They don't even care about the second boat in the class finish time.

TikPete... its called a yardstick for a reason.

The Primary yardstick is a thistle. the rating will never ever change for a thistle... its the standard which all other boats are compared with. Other boats are designated as secondary yardsticks .... their ratings change very very slowly.

If a rating is not changing... then the boat is being optimally sailed relative to the yardsticks.

Or... the actual speed improvement can not be measured with the amount and quality of the data collected.

the Mid atlantic region could only turn in two or three regattas worth of weekend buoys race data in 2008 because most of the racing is now one design and times were not recorded.

Jake's proposal that statistics will fine tune a measurement rating is merely a dream because the amount of data needed is just not out there to resolve small performance differences.

Even if the new Hobie F18 is a bit faster... Handicap racing will never measure the speed improvement due to the noise of boat racing against a Nacra 20 or a Blade F16.

He presumes that the measurement rating table is not accurate and requires some fine tuning with statisitcs.
To support this notion, he should at least identify boats in the measurement ratings that need some fine tuning with the performance data relative to each other. The sailors who use Texel or SCHRS are not out their complaining.

My view, is that the rating systems are about as accurate as you are likely to get. The differences are how they deal with changes and new designs in time. Measurement rules have a clear advantage.

There is a reason the ratings don't use several decimal places in the tables.

Most of the big boat ratings experts don't think you will be able to do better then 2.5%.... simply based on the nature of racing and the time of the race. Eg... if you don't get a lane on the first beat... you are slotted to a poor rounding round A mark... no matter how fast you are you can't use it on the first 1/4 of the race .... and the clock keeps on ticking.

It's a lot easier to get the data on a boat class measurments once then continually collect race results. If you get creative and change your sail ... then pay the 20 bucks and get it independently measured for your personal rating certificate.

The latest design by Ashy may be faster... but won't be measured using Portsmouth ratings of different class boats.


Geesh - I'm standing right here...no need to refer to me in the 3rd person. I don't have time to digest why you believe I'm misguided here but will try to do so tonight.


Jake Kohl
Re: Rating rant [Re: _flatlander_] #165658
01/21/09 07:09 PM
01/21/09 07:09 PM
Joined: Feb 2004
Posts: 3,528
Looking for a Job, I got credi...
scooby_simon Offline
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Originally Posted by flatlander18
Scooby,

Forgive me if this has been explained before...

Why, in SCHRS ratings, are all one-up boats listed with 75kg crew and all two-up boats listed with 150kg crew weight? Or, without regard to class minimum crew weights?


SCHRS uses the average weight for a person worldwide as the defiined crew weight.

Class rules are exactly that; class rules. SCHRS does not impose any rules on the classes. If they wish to impose rules on their sailors, that is up to them.

There are no current plans for changes to the SCHRS rating engine at present; we are still waiting for a number of measurement certificates from some classes to be able to confirm their ratings, the Nacra F17 being the most pressing.



F16 - GBR 553 - SOLD

I also talk sport here
Re: Rating rant [Re: Jake] #165661
01/21/09 07:27 PM
01/21/09 07:27 PM
Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Mark Schneider Offline
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Mark Schneider  Offline
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Joined: Jun 2001
Posts: 3,116
Annapolis, MD
The variance in the finish times of the top 5 finishers of a one design class is about 2.5 to 5 %. This has to do with sailing skill and luck. It's the intrinsic variance in the game.

So performance based handicap ratings between different classes will have a limited precision as well and won't resolve the subtle changes in design that develop over time. It will take a lot of data to get this level of precision around an accurate rating. If a game changing innovation shows up while you could detect it in the results quickly, the PN system would adjust for that change over three years by the standing policy. Also... you would need a lot of data to measure a significant difference.

You suggestion to combine the two methods presumes that something is wrong with the current measurement rating set that must be fixed. I don't see that example in SCHRS or TEXEL You argue that design will lead to game changes and I don't see any game changers in the formula classes... In fact the curved A class boards proved not to change the game as far as the top guys in the class are concerned. Nobody is talking about the new Hobie F18 as a game changer.

Why change?
Sailors don't care about the race results being fair next year... they care about the race they just completed. If it's not fair... it's not fun and they won't be around in three years when the fair result could be calculated. For a new racer starting with an old design... it is tough enough to get up to speed to sail to their rating. If they think the ratings for the hot new boat are unfair.... its another barrier to keeping them in the game.

An alter Qualifer event is very difficult to handicap with a Hobie 14 racing against a Tornado or supercat 22 by design. Throw in rarely raced designs like the CFR 20 and the Marstrom 20 and its really tough to do this job fairly.

IMO a measurment rating would be fairer. I have come 180 on this one and Carl Roberts and Wouter Hinjck should have a quiet giggle here. Dave Inham and I disagree on the basic premise of handicap racing so he can't giggle. he doesn't like the whole idea. (grin)


crac.sailregattas.com
Re: Rating rant [Re: Mark Schneider] #165665
01/21/09 11:17 PM
01/21/09 11:17 PM
Joined: Oct 2005
Posts: 951
Brisbane, Queensland, Australi...
ncik Offline
old hand
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Joined: Oct 2005
Posts: 951
Brisbane, Queensland, Australi...
The average weight for persons used for commercial vessel stability calculations in Australia is being increased from 75kg to 80kg. This is due to social changes affecting engineering rather than due to a safety margin being added.

A measurement system may/does work well for catamaran classes but they would be more inaccurate for monohulls. More measurement data would certainly be required for a dinghy because hull shape is more influential on dinghies than cats. Also, crew weight is anecdotally a more significant influence on performance for a dinghy than a cat so this would have to be accounted for.

Re: Rating rant [Re: Mark Schneider] #165672
01/22/09 05:00 AM
01/22/09 05:00 AM
Joined: Feb 2006
Posts: 3,348
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"Sailors don't care about the race results being fair next year... they care about the race they just completed. If it's not fair... it's not fun and they won't be around in three years when the fair result could be calculated."

Agreed.

Re: Rating rant [Re: fin.] #165674
01/22/09 05:32 AM
01/22/09 05:32 AM
Joined: Nov 2005
Posts: 64
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wirebound Offline OP
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Why donít we have just one rule? Itís a simple question, why does every nation need to have their own rule? If we all got behind one system and not diluting the pool of resources then the measurement rule will get sharper. At the moment there is holes in every rule, PY lack of results, SCHRS has boards aspect ratio, weight etc. We work off one set of racing rules why not one measurement rule? The current set of rating rules are flawed and donít react fast enough to the market, we are talking years to react, in keel boats there is a big adjustment if a boat is seen as a rule bandit. We (I) have been on talking about this for years and still we get small to no movements. I think that is why most people like PY because it reacts much faster to the market than the measurement systems, it might not be perfect but at least it tries to keep all the boats in the centre, unlike the measurement rules that cannot see the difference between stock sails and custom sails etc, okay I'm ready to get flamed

Re: Rating rant [Re: wirebound] #165678
01/22/09 08:02 AM
01/22/09 08:02 AM
Joined: Jun 2001
Posts: 3,906
Clermont, FL, USA
David Ingram Offline
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David Ingram  Offline
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flip flopper


David Ingram
F18 USA 242
http://www.solarwind.solar

"Do or do not. There is no try." - Yoda
"Excuses are the tools of the weak and incompetent" - Two sista's I overheard in the hall
"You don't have to be a brain surgeon to be a complete idiot, but it helps"
Re: Rating rant [Re: David Ingram] #165679
01/22/09 08:38 AM
01/22/09 08:38 AM
Joined: Feb 2004
Posts: 3,528
Looking for a Job, I got credi...
scooby_simon Offline
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Originally Posted by ncik
The average weight for persons used for commercial vessel stability calculations in Australia is being increased from 75kg to 80kg. This is due to social changes affecting engineering rather than due to a safety margin being added.

A measurement system may/does work well for catamaran classes but they would be more inaccurate for monohulls. More measurement data would certainly be required for a dinghy because hull shape is more influential on dinghies than cats. Also, crew weight is anecdotally a more significant influence on performance for a dinghy than a cat so this would have to be accounted for.


Mono's also plane and have symetric Spi's this also makes a massive difference (I know the Shearwater Cat has a Sym).

Originally Posted by wirebound
SCHRS has boards aspect ratio, weight etc.


What is wrong with aspcet ratio is is the most dominant factor in "normal boards".

Very thin boards do not perform at low speeds (I'm talking about aspect ratio > 6)

Very fat boards do OK in low speeds but suffer in fast.


Someone could choose to design very short and thin boards that get hit quite hard unser SCHRS, but why do it? Why would someone choose to design someting that will perform badly?


F16 - GBR 553 - SOLD

I also talk sport here
Re: Rating rant [Re: David Ingram] #165722
01/22/09 01:47 PM
01/22/09 01:47 PM
Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Mark Schneider Offline
Carpal Tunnel
Mark Schneider  Offline
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Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Quote
flip flopper
_________________________
David Ingram
F18 #672
http://www.naf18.com


So True.... but better to be on the right side of history eventually.... (see Bush v Gore)


crac.sailregattas.com
Re: Rating rant [Re: David Ingram] #165759
01/22/09 04:18 PM
01/22/09 04:18 PM
Joined: Nov 2005
Posts: 64
W
wirebound Offline OP
journeyman
wirebound  Offline OP
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Posts: 64
I'm so touched to be called a Flip Flopper I feel as if I've made it, Wow! did you come up with that all by yourself or did your baby brother help you? What a wingnut! ( Sorry David Ingram)

Last edited by wirebound; 01/23/09 03:59 AM.
Re: Rating rant [Re: wirebound] #165802
01/22/09 10:21 PM
01/22/09 10:21 PM
Joined: Sep 2002
Posts: 3,222
Roanoke Island ,N.C.
Team_Cat_Fever Offline
Carpal Tunnel
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Roanoke Island ,N.C.
Originally Posted by wirebound
I'm so touched to be called a Flip Flopper I feel as if I've made it, Wow! did you come up with that all by yourself or did your baby brother help you? What a wingnut!


I don't think he was talking to you. Read a few posts before yours, then apologize.

"IMO a measurment rating would be fairer. I have come 180 on this one and Carl Roberts and Wouter Hinjck should have a quiet giggle here. Dave Inham and I disagree on the basic premise of handicap racing so he can't giggle. he doesn't like the whole idea. (grin)" Mark Schneider


"I said, now, I said ,pay attention boy!"

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