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Re: Portsmouth DP-N [Re: Bob_Curry] #282362
04/07/16 11:31 AM
04/07/16 11:31 AM
Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Mark Schneider Offline
Carpal Tunnel
Mark Schneider  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Dave and all

I agree with Bob here
Quote


Posts: 741
"Maybe playing nice isn't all it's cracked up to be?"

It took awhile but you finally figured it out! D-PN is dead


It is UP TO EACH REGATTA CHAIR and Open Class fleet to pick something else.

A) Continue with the flawed and dated USPN portsmouth

or Change to....

B) ISAF run SCHRS measurement system.

C) Texel round the island measurment System.

D) Britsh RYA portsmouth system.

E) Australian VIC system.

IF US Sailing and the MHC were to run a handicap regatta they would have to choose a system from the ones above or make up something new. Otherwise, they have nothing to do with this choice.

Now, are you actually asking that US sailing pick one and recommend it?


crac.sailregattas.com
-- Have You Seen This? --
Re: Portsmouth DP-N [Re: Mark Schneider] #282363
04/07/16 02:55 PM
04/07/16 02:55 PM
Joined: Dec 2001
Posts: 5,590
Naples, FL
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,590
Naples, FL
which one is best suited for factory boats on a windward/leeward course?

Which one is best suited for distance course which may NOT involve all points of sail equally?

Which one is best suited for "ratings beater" modifications?


Jay

Re: Portsmouth DP-N [Re: waterbug_wpb] #282366
04/07/16 08:40 PM
04/07/16 08:40 PM
Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Mark Schneider Offline
Carpal Tunnel
Mark Schneider  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Hmm.... what game do you want to play....

Do you want to stand at the bar and say
"I won the race with exactly the right rating system which favors my boat?"




crac.sailregattas.com
Re: Portsmouth DP-N [Re: Mark Schneider] #282367
04/08/16 05:05 AM
04/08/16 05:05 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by Mark Schneider
Hmm.... what game do you want to play....

Do you want to stand at the bar and say
"I won the race with exactly the right rating system which favors my boat?"




Sadly, there are quite a few of those.


Jake Kohl
Re: Portsmouth DP-N [Re: Ventucky Red] #282369
04/08/16 10:46 AM
04/08/16 10:46 AM
Joined: Nov 2011
Posts: 381
SE MI / NE IN
rehmbo Offline
enthusiast
rehmbo  Offline
enthusiast

Joined: Nov 2011
Posts: 381
SE MI / NE IN
FWIW, CRAM will be evaluating SCHRS this summer for our Portsmouth fleet races. Official results will remain with DPN but will be scored via both methods. We'll review the impact and make a decision at the end of the season whether to adopt for 2017.

Of course our scoring officer sails an older Nacra F17 with a sweet DPN number so he might be a bit reluctant laugh


Jeff R

H18, C2 USA1193
cramsailing.com
crescentsail.com
Re: Portsmouth DP-N [Re: rehmbo] #282370
04/08/16 12:26 PM
04/08/16 12:26 PM
Joined: Jun 2001
Posts: 3,116
Annapolis, MD
Mark Schneider Offline
Carpal Tunnel
Mark Schneider  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 3,116
Annapolis, MD
So the assumptions NECESSARY for portsmouth to work..

There is a FLEET of Nacra F17s..
So... is there a fleet... was there a fleet and how big of a fleet of F17s was there ever?


This Fleet of F17s races against a fleet of Yardstick boats... (Hobie 16s, Nacra 5.8's Prindle 19s and now F18s..) So... lets be generous and say... that a fleet is 3 to 5 boats.... Show us race results for 20 races of nacra F17s... racing a fleet of one of these yardsticks. (That is 1/5th the number used to determine a PN rating by portsmouth.... for a wind range.... eg B2 / B3.

Otherwise... you are making an educated guess. In that case, the Portsmouth/PHRF board should meet yearly and guestimate a new rating table that the board believes is "fair".

The pitfall in saying... you will evaluate the handicap system by comparing the results at the end of the year is that you wind up goring somebody's ox with the choice ...based on their season results.

It would be wiser to agree on some criteria before hand and then measure the season against your essential factors.

Another thing you might consider is take the times on your one design classes and then use Sailwave to calculate the rating each boat in the one design fleet sailed to. It will give you some valuable perspective in evaluating ratings tables.

It really sucks when you realize that you just turned in a 4 th place performance on your nacra F17 that equals what a well sailed Hobie 16 would have done. (Bottom line... its the sailor... not the rating that matters)

Perspective on the numbers matters.

Good luck


crac.sailregattas.com
Re: Portsmouth DP-N [Re: Ventucky Red] #282371
04/08/16 12:29 PM
04/08/16 12:29 PM
Joined: Aug 2007
Posts: 3,969
B
brucat Offline
Carpal Tunnel
brucat  Offline
Carpal Tunnel
B

Joined: Aug 2007
Posts: 3,969
In a way, Jay hit the nail on the head. I think the most valuable thing the MHC can do is provide a list of the systems, the pros and cons of each (for OAs and competitors), some helpful tips to use them, and publish that.

We don't own, and cannot force, these systems to change. We can help our constituents navigate the existing systems, and provide feedback to the system owners for future consideration.

Mike

Re: Portsmouth DP-N [Re: Mark Schneider] #282374
04/08/16 02:58 PM
04/08/16 02:58 PM
Joined: Nov 2011
Posts: 381
SE MI / NE IN
rehmbo Offline
enthusiast
rehmbo  Offline
enthusiast

Joined: Nov 2011
Posts: 381
SE MI / NE IN
Originally Posted by Mark Schneider
It would be wiser to agree on some criteria before hand and then measure the season against your essential factors.


Good Point. As we primarily do W/L races, I wonder what those factors would be... Gonna have to think about this a bit more.

I think we have a general consensus (at least in our CRAM officers discussion) that hanging on to a system that is no longer properly maintained is a bad direction. I only see SCHRS or Texel as the legitimate options. Its a least of evils situation I suppose.

Anyway, looking forward to hearing opinions on the pluses and minuses of each.


Jeff R

H18, C2 USA1193
cramsailing.com
crescentsail.com
Re: Portsmouth DP-N [Re: Mark Schneider] #282392
04/11/16 08:16 AM
04/11/16 08:16 AM
Joined: Dec 2001
Posts: 5,590
Naples, FL
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,590
Naples, FL
Originally Posted by Mark Schneider

Do you want to stand at the bar and say
"I won the race with exactly the right rating system which favors my boat?"




Well it seems there are plenty who say the opposite:

"I LOST the race today because the rating system favors (insert name) boat"

So I wouldn't enter my 1984 Yugo beater into NASCAR event and expect them to come up with a handicap number to allow me to win.

It only makes sense to me that I figure out which rating system favors (or at least doesn't penalize) my particular boat's nuances (off-wind beast, downwind sled, pinching machine, etc) if I wish to stay near the top of the finishers, right?

Because learning to sail better, paying for coaching, and maintaining my equipment certainly won't put me up near the podium, right?

Would we see gravitation by sailors to events using this thinking if different rating systems were used by different events? So one class of boats may prefer DPN, another PHRF, a third SCHRS.. and only attend those functions?


Jay

Re: Portsmouth DP-N [Re: waterbug_wpb] #282438
04/13/16 10:10 AM
04/13/16 10:10 AM
Joined: Jun 2001
Posts: 733
Home is where the harness is.....
Will_R Offline
old hand
Will_R  Offline
old hand

Joined: Jun 2001
Posts: 733
Home is where the harness is.....
I was asked to be part of the SCHRS Technical Committee near the end of 2015 and agreed to help. Since I'm new to the process, I still have a lot to learn about what goes into the model and how ratings are produced and adjusted; however there were a couple of items that I think are useful in this discussion.

- SCHRS is actively managed, a lot of data is gathered, compiled and analyzed in order to validate current ratings and develop changes
- The process to update ratings is very methodical; both the reasons for, and the impact of changes are analyzed and reviewed by the committee prior to being finalized
- When changes occur, they are done via small, incremental steps so as to avoid "knee jerk" reactions and over corrections while continuing to move everyone closer to the middle

The document that I reviewed was very thorough in its analysis, explanations of changes, reasons for the proposed changes and contained plenty of supporting documentation. I would argue that they are doing a very good job of fairly rating boats in such a way as to provide the most level playing field possible. They have a model and are using statistical analysis of race data to validate the model and make minor changes as necessary... Are there outliers? Probably, but you're going to find that anywhere.

At the end of the day though, I think this is a more sound approach than the 100% statistical analysis approach of DPN. There would likely be little for the USSA to do in order to adopt SCHRS; heck, it might save some time and money to adopt this system as there would no longer be a need for the effort which is currently put into DPN. Additionally, from a statistical perspective, you now have a larger data set to work against; by increasing the width and depth of the data, the confidence goes up and the model gets better.

Re: Portsmouth DP-N [Re: Will_R] #282439
04/13/16 10:26 AM
04/13/16 10:26 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by Will_R
I was asked to be part of the SCHRS Technical Committee near the end of 2015 and agreed to help. Since I'm new to the process, I still have a lot to learn about what goes into the model and how ratings are produced and adjusted; however there were a couple of items that I think are useful in this discussion.

- SCHRS is actively managed, a lot of data is gathered, compiled and analyzed in order to validate current ratings and develop changes
- The process to update ratings is very methodical; both the reasons for, and the impact of changes are analyzed and reviewed by the committee prior to being finalized
- When changes occur, they are done via small, incremental steps so as to avoid "knee jerk" reactions and over corrections while continuing to move everyone closer to the middle

The document that I reviewed was very thorough in its analysis, explanations of changes, reasons for the proposed changes and contained plenty of supporting documentation. I would argue that they are doing a very good job of fairly rating boats in such a way as to provide the most level playing field possible. They have a model and are using statistical analysis of race data to validate the model and make minor changes as necessary... Are there outliers? Probably, but you're going to find that anywhere.

At the end of the day though, I think this is a more sound approach than the 100% statistical analysis approach of DPN. There would likely be little for the USSA to do in order to adopt SCHRS; heck, it might save some time and money to adopt this system as there would no longer be a need for the effort which is currently put into DPN. Additionally, from a statistical perspective, you now have a larger data set to work against; by increasing the width and depth of the data, the confidence goes up and the model gets better.


Portsmouth also handles dingy racing in the US so it would be a situation where a system is put in place along side portsmouth in the US. SCHRS is strictly catamaran handicaps. There is an english portsmouth system that is maintained (RYA), I believe that also handles dingies.

This isn't necessarily a problem - just pointing that aspect of Portsmouth out.


Jake Kohl
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