Introduction to performance handicaps
How does the YV Performance Handicap System work?
Some recent discussion of performance handicap changes on Wednesday evening races prompted me to offer some explanation of the YV Performance Handicap System and how handicaps are recalculated.
All boats at RYCV have a performance handicap.
By definition this performance handicap indicates the performance of each boat in the Club relative to other boats in the Club.
Please do not confuse a measurement rating (such as AMS or IRC) with a performance handicap. Ratings are calculated from measurements of the boats hull, rig and sails, and once calculated will not change unless changes are made to the boat, whilst a boats performance handicap will probably change after each race.
Performance handicaps are generated and recalculated in accordance with the Yachting Victoria Performance Handicap Rules.
A copy of these Rules are always on the YV website at http://www.clubmarineseries.com.au/assoc_page.cgi?c=0-10084-0-0-0&sID=308906
Since September 2014, Royals has been using a software package called TopYacht. This has replaced the system we have used for many years, namely PAT. TopYacht calculates the results of each race and also recalculates the handicap for each boat for the next race.
When a boat enters a club race, it will be allocated a performance handicap for that race, called its Allocated Handicap (AH). This AH will be taken from the TopYacht database or will be supplied by the Club Handicapper).
This performance handicap is a single figure Time Correction Factor (TCF) and is used to convert a boats elapsed race time to a corrected time. Thus if a boat takes 100 minutes to complete the race and its Performance Handicap (or TCF) was 0.75 the its corrected time (CT) will be 75 minutes (100 x 0.75).
The boat with the lowest corrected time (CT) is the race winner.
After each Club race the TopYacht programme will calculate data for each boat, namely
1. The corrected time (the boat with the lowest CT being the winner).
2. The back calculated handicap (BHC).
This is the handicap that each boat actually achieved in the race.
Boats in the top half of the results list will have BCH values above their AH
and boats at the bottom half below their AH.
3. The Calculated Handicap (CHC) for each boat.
This is the handicap for each boat in its next race.
The CHC is calculated as follows
CHC = 2/3AH+1/3 BCH
Thus for example if the AH was 0.800 and the BCH was 0.815, then
However if you read the YV Handicap Rules, you will note terms such a LBCH, LBCHU, LBCHL and LBCHD.
|LBCH||Limited Back Calculated Handicap||4%|
|LBCHU||Limited Back Calculated Handicap Upper||4%|
|LBCHL||Limited Back Calculated Handicap Lower||4%|
|LBCHD||Limited Back Calculated Handicap Discard||8%|
The YV Rules have recognised that on some occasions other factors come into race results. There could be a drop in wind soon after part of the fleet finishes or same boats could have a problem on the water but choose to finish. Thus we use "clamps". Clamps limit the change of the Back Calculated Handicap (BCH) and produce a Limited Back Calculated Handicap (LBCH).
Currently the clamps are 4% on handicaps and 8% on a discard. Thus if the BCH is greater than 104% or between 96% and 92% the BCH is limited to 104% and 96% respectively (clamping the BCH to 4%). However if the BCH is less than 92% of the AH then the result is discarded for handicap recalculation purposes and the CHC remains unchanged.
To illustrate how the recalculation system works I have calculated the results for the Wednesday evening race of 2nd February 2013
|SAMPLE CALCULATON OF HANDICAPS|
|(Wednesday evening race 2nd February 2013)|
|R650||THE STIGS AUDI ETC||862||823||95||LBCHL||96%||828||851|
This sample calculation illustrates all the workings of the YV Performance handicap calculations, namely
a. Galaxy, Duckmobile and Mainstay all had BCH values greater than 104%, thus their BCH was clamped at 104%.
b. Moneypenny, The Bookmaker, Circe, Mika, Just Quietly, Top Gun, Eneseay, Next Moment, Alien and Paragon all had BCH values between 96% and 104% and thus their actual BCH was used.
c. The Stigs Audi, Ikon, Cousin It, Merlion, and Laurelle all had BCH values between 96% and 92% and thus their BCH was clamped at 96%.
d Executive Decision had a bad race and the result was discarded because the BCH was less than 92% (note, although his CHC was noted as 870 in the results, this was corrected at a later date).
This is how the YV Performance System works and how results are recalculated.
On a historical note, performance handicap calculations have changed over the years. In the 1960's boats that came first, second or third had their handicap increased by a fixed %, this later changed to recording the boats last 8 BCH's, discarding the best and two worst results and averaging the remaining 5. The change to the current method (as described above) has been used for about 4 years.
The current recalculation method is more immediately responsive to changes in the boats performance and requires fewer results for a boat to have a valid handicap.
If you have any issues, please contact the author in the first instance and I can usually answer them. The Performance Handicap System has been operating in its current form for about 60 years.
It is not perfect, if it were we would have all boats tied for first place each race.
I always welcome constructive comment and/or criticism, and particularly if you can see a way we might improve what we have.John DuffinClub Handicapper RYCVChair YV Performance Handicap Committee.