ORC presentation at LYC 1/27

[Bob H]

GBCA received this recently and if you have an interest in other handicapping systems, you may find it worthwhile to attend.
-Bob H.


To: All Sailors and PHRF Certificate Holders


The Galveston Bay PHRF Committee invites you to a discussion of rating rule options and a presentation of the Offshore Racing Congress'  "ORC Club Rule"

We are pleased to have Mr. Dobbs Davis of Annapolis Md. make the presentation and lead any discussion of various rules.

Dobbs, who is the head of ORC's promotion and development, is a well known professional sailor, having participated in virtually all  of the worlds major races. He is an International Measurer for multiple rules;  a prominent journalist, and a popular  panel moderator.

The purpose of this gathering is not to replace PHRF, as there will always be a PHRF fleet on Galveston Bay, but to offer information providing options for a scientific and more precise method of handicapping and scoring races for those who so desire.

U.S. Sailing has recently reached an agreement with ORC to administer their rules in the US, and issue their Certificates upon receiving the minimal confirming measurements done locally.

Please plan to join us on:

Wednesday  January 27                         Lakewood Yacht Club
Refreshments beginning at 6 PM           Presentation at 6:30 PM
       

[Bee]

This was tried by Andrea Todaro beginning, I believe, in 2005. I based this on the fact that Stinger's first ORC Club certificate that I can find is dated 2005.  ORC is quite a bit different from PHRF because it uses a two number system.  One multiples elapsed time like PHRF TOT,  the other distance.  The numbers are based on what I assume is an EXCEL style Velocity Prediction Program.  I have one of those but I could never get the numbers it gave me to match ORC. Unlike ORC there is little cost for ORC CLUB and not much in the way of measurement requirements to get the numbers.  If I remember correctly you can have as many certificates as you would like.  For example, Stinger could have a class sail version and a full PHRF version.  One does have to provide the mast measurements as well as sail complement.

When Andrea came up with this, I initially thought it would be a good idea.  It was the mathematician in me. After a bit more thought I realized that it would not go over well because of the fact that it could be difficult to  estimate finish position relative to competitors.  With modern smart phones, this would probably no longer be much of an issue. I also realized that politically it might be a disaster.  Unlike PHRF, one cannot easily argue with the rating authority to get your rating changed. It is all  based on "rock solid" measurements.  If you are unhappy with your numbers tough luck.  The numbers I received did changed each year.  Moreover, two J105's with different weights but identical sail complements can actually have different numbers.  Doesn't seem right but then 105's are not necessarily identical.

The system was tested in at least a couple of HMR's. In one of those, Stinger finished 4th in ORC.  I used the finish times of the top ten boats and calculated where they would have finished.  Not much changed.   A couple boats swapped positions but that was about it.  Stinger finished 4th in PHRF and 4th in ORC.

I made quite a few comparisons of the two systems and ultimately concluded that I had insufficient statistics in order to really analyze the difference.  My first question to Dobbs would focus on that.  Just how big of a difference is there.  My simple comparisons said "not much."  He should have much more info now

I attached a copy of the 2005 ORC Club Certificate.

[dc1sail]

The ORC is indeed based on a sophisticated Velocity Prediction Program (VPP) which is continually being updated.   

Quoting from the ORC web site:
   
As a result of having the complete matrix of predicted boat speed at various wind strengths and directions, ORC rating systems can therefore provide a variety of methods to calculate corrected time.

Scoring options offered include the most sophisticated, where the boat's performance is taken in consideration depending on the wind conditions, but also simple scoring options using single number scoring coefficients in either Time on Time or Time 0n Distance formats. Simple scoring options also include Performance line as a combination of Time on Time (ToT) and Time on Distance (ToD). There is also the Triple number system that uses three different Time on Time coefficients to be used in light, medium and heavy breezes. All simple scoring options are also given for either Inshore (windward-leeward) or Offshore races.
This wide variety of scoring options may look complex, but it is actually one of the strength of the ORC rating systems to offer race managers a variety to choose from that best suits their fleet, their race type and their race conditions.

The factors race managers should consider when choosing which scoring type to use include:
•   type and level of the fleet - better to use simple systems for club-level racing
•   type of race- windward/leeward or an offshore race
•   the difference between fastest and slowest boat - important to know how to divide classes and to combine entries for overall prizes
•   prevailing weather condition- are they steady or variable during the race
•   tradition of particular type for eg, Time on Time or Time on Distance
•   is there current in the area, and can it be predicted - if not, then ToT is better than ToD

Because the ORC VPP can predict the performance potential of different boat types, it can rate them fairly against each other in any range of wind conditions and course types. In this way Performance Curve Scoring can make handicap yacht scoring significantly more fair than any single number scoring approach.


The ORC database contains over 70,000 boats.  Many production boats are included such as S2's, Melges, J Boats, etc.....it is easy and inexpensive to create a certificate, just copy the data for an existing boat of your type and then make any changes to reflect your sail inventory, rig or crew weight. You typically do not have to get boat measured unless you modified it.  I created a test ORC certificate for my J/109 just to get the polar curves - the ORC VPP can handle code zero's and reaching kites and gives the cross over points between jibs, CO and running kites for each wind speed.  We have found the VPP Target boat speeds/ angles very accurate except for deep running.

If you find a single point rating system frustrating for handicap racing then you might find the ORC presentation interesting.  Will it solve all the handicap problems - I doubt it !! ...... but it might make handicap racing a bit more fair?   A big question is how the various race committee's will deal with this.  It may add to their work load?

Dave Christensen
S/V Airborne

[Bee]

I am not sure ORC Club's VPP is as you say, "very sophisticated."  I'm not saying its bad, but predicting how a hull moves through the water is extremely complicated.  Even with a several thousand core super computer and potentially months of commute time,  its not clear how well one can fit a two parameter curve to the process.  What VPP's use are empirically derived (statistical fits hopefully) formulas to convert multiple measured values into parameters that can be used to predict any given boat's polars.  They do revise the program every year, so the numbers can change on a yearly basis. 

What's good about ORC is, at least in my opinion and unlike PHRF, the result is a more mathematical and more accurate prediction of boat speed under various wind conditions.  It is why there are different numbers for different style races.  Most of the boat polars one uses are the result of a VPP.  The polars I have for Stinger seem fairly accurate until the winds exceed 20.  All bets are off then.  It would be very interesting to test ORC CLUB in all the W/L, as well as Icicles and Rum Races.  I certainly would have no trouble getting a new ORC certificate for that purpose.  I don't recall it being all that expensive. If we had enough boats we could run side-by-side comparisons to see just how much difference ORC makes.  Might be interesting to find out if ORC CLUB has done this and actually compared results.  I bet they have.

I think Andrea's goal in trying ORC CLUB was an attempt to find a system that did a better job of leveling the playing field then PHRF did. Early on, I had hoped that Andrea's experiment in the HMR would result in enough information to say that we should at least try ORC Club in a variety of race conditions.  Unfortunately, ORC CLUB for the HMR was not popular and she dropped it after a couple tries.  I hate to say it but I was probably one of the bigger complainers.

[Bee]

Early this afternoon, I had a short conservation with John Barnett about ORC.  I surmise that he knows a lot  about this and I conclude that the discussion will be very interesting.

[JayZ]

I thought i would bring this to the top as a reminder of the ORC presentation and the PHRF annual meeting tomorrow which will simply be a Q&A after the ORC presentation.



"The Executive Committee of the Performance Handicap Racing Fleet of Galveston Bay (PHRF-GB) invites you to the Annual Meeting of the fleet members to be held on Wednesday, January 27, 2016, at Lakewood Yacht Club. A social time with refreshments will begin at 6:30 PM, and the meeting will begin at 7:00 PM.

The official Annual Membership Meeting will begin immediately following the previously announced Offshore Racing Congress presentation on the "ORC Club Rule". The PHRF-GB agenda will include a review of recent revisions to the adjustment factors for headsails and asymmetrical spinnakers. Additionally, committee members will be available to answer questions about the new rating procedures, rating adjustments or other rating issues.

We hope that you will be able to attend."