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Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: waynemarlow] #219242
09/11/10 04:54 AM
09/11/10 04:54 AM
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couldn't resist it
Codblow Offline
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I believe this could be the way ahead.
Saiwave and programms like Hal can report data direct to RYA uks PY compterised system , which will in turn can send back suggested ratings for racing , honed to your conditions at your club, regionally national ,class specific or even the "dreaded" personal level, the more data rec'd the better it gets .

Takes the best of a measurement system and the fine tunes to your requirements.

At the begining of the season I spoke to Bas Edmunds of RYA who runs the system and he has/is set up system to deal with schrs formatt ratings , texcel wouldnt be a prob either .

This system can butts data to YOUR requirements and report back , it is automated once set up and not a bunch of dudes sitting behind closed doors dreaming up numbers.

At my club we are setting up to do this , unfortunately the wheels of progress are slow , but once the IT dudes get their act together (unfortunately another story ) it should be in place for next season with a years historical data to be assessed and provide ratings for next year.

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Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: _flatlander_] #219269
09/12/10 03:25 PM
09/12/10 03:25 PM
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Originally Posted by _flatlander_
Originally Posted by HMurphey
But he has a very valid point .... as I try to compete on a P19MX that has a "DPN" rating set by Mr Randy Smythe's finishes. Do you think I could ever sail a P19MX anywhere near close to Randy's ability???? I would like to see a handicap system based on physical measurements of the boat .... not on a few races w/ one of the best sailors in the world setting the pace ...

Harry
Ditto here, David Webb, of Wichita, ruined the P15 number (76.2). You try sailing one two tenths off a Hobie 16! (76.0) Texel numbers look much better.


so you are saying that you want a handicap system based on your potential and not the potential of the boat? That doesn't make sense.


Jake Kohl
Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: Jake] #219274
09/12/10 04:22 PM
09/12/10 04:22 PM
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Mark Schneider Offline OP
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No.... What they are saying is that for their small class (P15 or P19MX) Classes which rarely get one design starts or hold NA's, the data are skewed by one rock star

One Rock star individual represents the majority of data points (first place boat in class) and that they are racing against yardstick boats (first place boat in class) that were not sailed by some one equally skilled.

They argue that the P15's performance is unrealistic. So, they believe that they are saddled with a rating that is an error.

This perception exists because the USPN system simply can't identify enough races of MANY higly skilled P15's against yardstick boats that are equally well sailed.

In rock star dominated ratings... Ratings (where the rock star competes against mortal sailors on yardstick boats) are set and then are VERY slow to change because of the two policies of USPN. (Results from races that are deemed outliers never make the database for the class AND a change in the PN rating will only change by 25% OF THE DIFFERENCE)

Portsmouth yardstick ratings work well when you have a strong one design fleet (No rock star domination of the fleet) which then race in Portsmouth races against other strong one design classes. Thus the results accumulated indeed reflect the assumption of Portsmouth Yardstick... ( a perfect race ready boat sailed perfectly with flawless strategy against yardstick boats sailed the same way) You can subtract the skippers out of the rating when this happens.

The P15 and P19mx sailors don't believe the skipper performance was extracted from the ratings.

The US Marstrom 20's... (Two boats) The CFR 20 (one boat) and the Nacra F20 (1 boat) will never be able to get ratings where the skippers performance can be extracted leaving just the boat.


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Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: Mark Schneider] #219275
09/12/10 05:07 PM
09/12/10 05:07 PM
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+1


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'When you have a lot of things to do, it's best to get your nap out of the way first.

Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: pgp] #219355
09/13/10 10:54 AM
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Regardless of which system is used (Portsmouth or measurement), the rating SHOULD be about the potential of the boat.

Just like in OD racing, if you're not sailing your boat to its full potential, you won't win, unless the guys on the other boats are less up to the task than you.

Someone learns a new (RRS-legal) technique to make the boat faster? OK, so they just got closer to sailing it to its potential. You can't master that trick? OK, you lose.

Simple is good...

Mike

Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: brucat] #219360
09/13/10 11:32 AM
09/13/10 11:32 AM
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Originally Posted by brucat
Regardless of which system is used (Portsmouth or measurement), the rating SHOULD be about the potential of the boat.

Just like in OD racing, if you're not sailing your boat to its full potential, you won't win, unless the guys on the other boats are less up to the task than you.

Someone learns a new (RRS-legal) technique to make the boat faster? OK, so they just got closer to sailing it to its potential. You can't master that trick? OK, you lose.

Simple is good...

Mike


Tten you HAVE to use TEXEL or SCHRS as PY will always factor in crew skill.


F16 - GBR 553 - SOLD

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Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: brucat] #219362
09/13/10 11:58 AM
09/13/10 11:58 AM
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Originally Posted by brucat
Regardless of which system is used (Portsmouth or measurement), the rating SHOULD be about the potential of the boat.

Just like in OD racing, if you're not sailing your boat to its full potential, you won't win, unless the guys on the other boats are less up to the task than you.

Someone learns a new (RRS-legal) technique to make the boat faster? OK, so they just got closer to sailing it to its potential. You can't master that trick? OK, you lose.

Simple is good...

Mike


You can look forward to complaining that the formula isn't "fair" under Texel or another measurement based system...which is my point - it's all an approximation.


Jake Kohl
Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: Jake] #219363
09/13/10 12:35 PM
09/13/10 12:35 PM
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I will say I have learned an awful lot of stuff from reading this thread.

Being a neophyte to this, as an observation wouldn't it be smart to use what ever system the championship organizers are using. I seem to remember there were two different governing bodies for the Triathlons a while back and one organization got little snippy about the athletes that were from the other organization and made the qualify under their system.



Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: erikcole] #219378
09/13/10 04:09 PM
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Jake - I agree, and have already mentioned that, every system has its pluses and minuses.

Erik - Just to clarify, the championship finals are run as one-design, on provided boats. The qualifiers (only) are the topic of discussion here.

Mike

TEXEL & SCHRS ratings: configuration declared (none?) [Re: SurfCityRacing] #220136
09/23/10 02:29 PM
09/23/10 02:29 PM
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Originally Posted by SurfCityRacing
Originally Posted by DennisMe

When it comes to organizing a race, Texel spends a lot of time and effort actually physically measuring freaky boats that show up.


To me, the best system would be one that would use fewer volunteer hours to implement. Let's face it, we don't have the enthusiastic volunteer pool that we once had. No one wants to measure boats when they could be drinking rum in the club.

Luckily for us here in Area G, most boats race in their one-design configuration.


I thank all boats that race One-Design.

2010 Jazz Cup the Hobie Miracle 20's were assumed to be be racing with spins (like Delta Ditch). Nemesis showed up on course without a spin, wrong rating, ... oh well, some at least report the config, ... S-->

Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: scooby_simon] #220137
09/23/10 02:36 PM
09/23/10 02:36 PM
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Originally Posted by scooby_simon

Tten you HAVE to use TEXEL or SCHRS as PY will always factor in crew skill.


Agree.

Reference: One-Design TCF-to-First

Fortunately, the One-Design gentlemen in Europe report Elapsed Times under Texel and SCHRS. More F18 data will be added if some U.S.-based races are found. Large fleets ~may increase teh difference between First, 1st, and mid-fleet. Small fleets do not always reduce the finish time delta.

Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: DennisMe] #220138
09/23/10 02:58 PM
09/23/10 02:58 PM
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Originally Posted by DennisMe
The only drawback I know of to Texel is that cruising cats have no chance against beach cats.


ref:
2010 Rated Weight (RW): catamarans <= 20ft = rw^0.300, multihulls >; 20ft = rw^0.325
2010 Rated Length (RL): catamarans <= 20ft = 1.15*RL, multihulls > 20ft = 1.0*RL
2010 Rated Sail Area (RSA): larger multihull RSA changes (see RSA.items )

There is compensation on Rated WEgiht (RW), Rated Length (RL) and Rated Sail Area (RSA) using Texel.2010. The compensation is useful for Corsair Trimarans some of the time. "Crusing Cats" ahve a challenge: Rated Weight (RW). Few Big Cats get on a a load cell, other than in Australia under texel.AUS/THAI.2010.

Last edited by slackwater_sf; 09/23/10 03:21 PM.
SCHRS & TEXEL: Rated Length, Crew Weight Calculations [Re: Codblow] #220139
09/23/10 03:17 PM
09/23/10 03:17 PM
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Originally Posted by Codblow
Texcel of the two - SCHRS has anomolies and a two tier system that biases boats MEASURED before a certain date with an advantageous rating against those built before that date but not rated ,2007 I think is said date (basically schrs assumes all boats MEASURED after "2007" have their waterline equal to overall length !!!-

TEXCEL MEASURES ALL BOATS THE SAME WAY .

Both systems are inheritantly flawed in the assumption that all cat sailers weigh 75 kgs .

yes you guessed it I'm a 118kgs solo sailor , with a boat built built pre 2007 with a significantly shorter waterline , but not MEASURED pre 2007 , that gets humped on hcap regularily !!I'll dig my hole now and batten down for flak .



No worries about getting in a hole, just volunteer to rate boats.

SCHRS uses a Rated Length adjustment (rating credit) for boats before 2007, when plumb bows became normal. Measuring for RL under Texel, similar issue, boats without plumb bows get a rating credit in the Rated Length. I take digital pics with a metric tape for Microsoft Visio scaling (no wetsuit in-water measurements)

Crew Weight:
The SCHRS calculator uses a whole crew person, rounding up/down when I put in 1.2 crew (I think).

The Texel.XLS uses a similar assumption on standard crew weight. However, the Texel.XLS allows WCD (?) Weight Crew Declared in Kilograms.

The WCD variable will change the TCF and corrected finish order results.

What's Normal?
One boat in the last two (2) years asked to use WCD. I said sure, suggesting show up the day of the race and you and your wife have to be in bathing suits to be measured on my scale. They declined as the "declared weight" difference was ~10 kg over the assumed/calculated WCD.

Same with weighing a boat: show up and get on the load cell.

Last edited by slackwater_sf; 09/23/10 03:34 PM.
Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: slackwater_sf] #220148
09/23/10 06:37 PM
09/23/10 06:37 PM
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Mark Schneider Offline OP
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EXACTLY!

Consider a professional one design race of Farr 40’s. In a 10 boat race… the perfectly sailed boat coming into the port tack lay line at the first mark and the equally well sailed boat in first place on the starboard lay line have the same rating.…. Port is tied for first in performance … However, this perfectly sailed boat will be 10th around the mark as the 9 starboard takers line up head to tail forcing him to sail to the end of the line. The variance in the portsmouth measurement rating is a function of a "sailboat race conducted according to the RRS. The nature of fleet sailboat racing is such that differences of 6 secs per mile or about 15 sec’s per hour can be expected simply do to sailboat racing variables. Slackwater provides some real world examples of time delta's in one design races where the time differences between first and the fleet or first and second are attributed to both the sail boat racing noise, plus sailing factor noise. Since these are one design data... they do not include differences caused by the boat design
So the variance is greater then 30 seconds per hour

In order to reliably detect a performance difference between two classes of boats or a design advantage within a class, you must have a real difference of double this noise value.

What this all means is that statements saying Portsmouth handicapping will be more accurate (when and if we get it right) then measurement ratings are simply wrong.

If both systems are working properly ... they are equally accurate and the precision is about the same.

The issue is that Portsmouth handicapping is simply broken.

SCHRS or Texel ratings are not broken plus they are transparent and timely.


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Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: Mark Schneider] #220149
09/23/10 06:53 PM
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Jake Offline
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All you're proposing is trading one system that has a weakness for the group of sailors that are sailing the boats for one that has a weakness accounting for the design nuances between boats.

Which doesn't matter unless someone actually ponies up with a proposal to the multihull council to be voted on.


Jake Kohl
Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: Jake] #220152
09/23/10 07:59 PM
09/23/10 07:59 PM
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Mark Schneider Offline OP
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First ... Proposal submitted... Draft report submitted... waiting for feedback from two readers.

Quote
All you're proposing is trading one system that has a weakness for the group of sailors that are sailing the boats for one that has a weakness accounting for the design nuances between boats


WHAT..

Ugh.... the sailors using Texel or SCHRS have not come forward with .... "weakness accounting for the design nuances between boats:

You are the only one asserting an equivalence between SCHRS (broken) and Portsmouth (broken) as a fact..

You assert that PN is potentially more accurate... (can't be) You haven't jumped up and said... SCHRS or TEXEL is too hard on XXX. They get the formula wrong. Finally, We don't see any of the sailors who are actually using texel or SCHRS jumping up and saying... Yeah... the system really is wrong for XXX class of boats.

Saying SCHRS ss flawed doesn't cut it. Stating a false equivalence is a good debate tactic... but that does not make it true.

The only critique so far is... ... yeah... texel can't rate big cats and beach cats fairly. But I don't care... The area qualifiers are open to cats 22 feet and under. The other critique was... well fat boys don't get fairly rated on Texel or SCHRS. Again.... irrelevant to this debate.

I have detailed all the systemic problems with portsmouth.
Stop equating the two systems as if they are equal. One is broken... the other one is not. Provide some testimonials that SCHRS or Texel is broken and then we can weigh the two systems... (I looked... I can't find any good critiques).

A better way to describe the current state of US beach cat handicapping is .. that it is now a PHRF like committee which takes the SCHRS rating for new boats and scales it for the USPN ranking.... and summarily corrects the ratings of other classes when they get out of whack after using bad data.
The data is just not there...... therefore the system is broken.

Fundamentally, this is a question of integrity... using a broken system is a joke.

Look you could take the point of view that we should just invent a Beach Cat PHRF to correct for US water density and light US breezes.

PHRF for beach cats could work... PHRF is very successful and it's cheap to administer ...It's integrity is based on the credentials of the PHRF rating committee which sits in each area. I race under it every Wed night.. I just don't pretend that my race results are averaged into a rating.



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Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: Mark Schneider] #220153
09/23/10 08:05 PM
09/23/10 08:05 PM
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Quote
PHRF is very successful and it's cheap to administer


Depends on your point of view. I know the skipper of the boat I sailed on thought that politiking his local PHRF board to get either his rating buffed or his competition's rating nerfed was as much a part of the wednesday night series as the actual races.

"its part of the game".

Not something I'd like to see in the beachcat world.

Re: Should Area Championships use SCHRS or TEXEL ratings? [Re: ThunderMuffin] #220155
09/23/10 08:29 PM
09/23/10 08:29 PM
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Mark Schneider Offline OP
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As I said... PHRF integrity depends on the people on the committee. sounds like a weak group.

Would I want Beachcat PHRF... no way!... SCHRS or Texel are transparant, timely and THEY WORK without emergency ad hoc fixes.

The last two of the three new US classes... CFR 20 and F16's had ratings SNAFU's... THE USPN committee acted like a PHRF group and fixed things.... I was part of the loop...

Now it's time to change over.

Last edited by Mark Schneider; 09/23/10 08:31 PM.

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Area Championships: Portsmouth, Texel, SCHRS [Re: Jake] #220160
09/23/10 11:07 PM
09/23/10 11:07 PM
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Originally Posted by ITEM.1
First ... Proposal submitted... Draft report submitted... waiting for feedback from two readers.
Good, trust it will get good reviews.

Originally Posted by ITEM.2
They get the formula wrong.

The concepts for rating formulas are similar ( link Rated Length, Rated Sail Area, Rated Weight). SCHRS is somewhat published, but not in Excel (?).

Originally Posted by ITEM.3
The area qualifiers are open to cats 22 feet and under.

Big cats might be a non-issue if defined by 22 ft LOA; weigh the crews & boats. Early Nacra F20.Carbon results were mush under SCHRS. Later, the F20's started correcting towards the front. The debate item might be big cats as defined by F18s vs. Prosail.40's and D-Class cats.

Originally Posted by ITEM.4
fat boys don't get fairly rated on Texel or SCHRS.

The sailors have to think it is fair: Weigh the Crews, it makes a difference. Normative arguments are about light air, can't have a light enough crew, heavy air gives an advantage to those with high Declared Crew Weights.


Originally Posted by ITEM.5
PHRF for beach cats could work..

Uhh, suggest use standard TCF's from Texel or SCHRS. PHRF TOD numbers get converted by local Race Organizers with Many Variants of conversion factors, from Monohull Assumptions, to a TCF that is non-aligned with SCHRS or Texel.

There will be conditions that favor one boat over another, suggest:
Heavy air, long boats with little Sail Area will generally do well, all things being equal.
Light air, never enough sail area on short boats will do well.
There are balanced courses for the races under discussion, non-balanced courses (long-distance) may cause an issue.

Curved boards will be a debate item to rate, suggest: a possible benefit in a breeze, a possible liability in lightish winds. The early Nacra F20.Carbon races in Europe were not pretty; corrected times improved with time in the boat (sound like a one-design?) from my limited view of the data.

Re: Area Championships: Portsmouth, Texel, SCHRS [Re: slackwater_sf] #220184
09/24/10 09:15 AM
09/24/10 09:15 AM
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Mike Hill Offline
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look at the history of IMS. I would hate for beachcats to go down that road. Creating expensive rule-beaters is a big problem that I don't see a solution for in Texel or SCHRS.

Here is a brief history of IMS.
http://en.wikipedia.org/wiki/International_Measurement_System



Mike Hill
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