BMYC Pennant
Brighton Marina Yacht Club
home > racing > handicaps > PY Handicaps methodology

PY Handicaps methodology

For those who are interested and have the time to read it - this is a summary of the methodology used for the last few years.

This methodology is due to be reviewed again in the next few months.

  1. This methodology has been derived from race results at BMYC since 2002, except for a section of 2003 from which results are missing.

  2. PY handicaps that were in existence at the beginning of 2002 were used as a starting handicap.  In practice the starting handicap appears not to matter for boats that have raced a lot – because it has been modified so much. But it is crucial for boats that have only recently started racing.

  3. For boats that joined since then, we used the first handicap they were given as their starting point – except where that starting point has been modified as below.  We discovered that there was not a linear relationship between IRC handicap and final PY handicap as calculated.  Boats with larger IRC handicaps had disproportionately better results that those with small IRC handicaps. So it is not appropriate to use uncorrected IRC handicaps as a guide to starting PY handicap. We drew a graph relating IRC and final PY handicap that described a curve. We have used this to determine initial handicap for boats with IRC handicaps that have started racing recently. But for other boats we use any appropriate sources such as Open PY Handicaps as determined by the Sussex Combined Handicaps Committee.

  4. For each race, a decision was made as to whether the results could be used for handicapping. Speciality and fun races were excluded.

  5. Each fleet in each of these races is treated separately as they may have had different courses.  Only fleets with more than three boats are used for calculations.

  6. For every boat in each race’s fleet a number of parameters are calculated as follows:

    • Tally (T) of the number of times each boat had raced so far. Increases by one each race.

    • Last Proposed TCF (LTCF) = Proposed TCF (see below) from the last race that boat was in – after the PY calculations have been done.  The LTCF changes progressively each race in accordance with that boat’s performance. If no previous race it was estimated (see below).

    • Proposed corrected time (PCT) = elapsed time / LTCF

    • Ideal TCF (ITCF)= LTCF x PCT / ACT

    • TCF Difference (TCFD) = ITCF – LTCF

    • TallyTCFDifference = TCFD / 10
      This means only a 10th of a recommended change happens each race. So that if a boat has an exceptionally bad race it does not have to much of a change.
    • Proposed TCF (PropTCF) = (LTCF + TallyTCFDifference)

  7. For each race's fleet the following parameter is calculated:
    • Average Proposed Corrected Time (ACT)=Σ(PCT x T)/ΣT
      This value is calculated in a way that gives more weight to boats that have raced more times.

  8. Initially the real PY Handicap would only change to the Proposed TCF if the change was greater than a value of 0.015.  But since February 2010, changes have only been made at the end of each Sunday series – by whatever value that is required.