I have used the Results Worksheet which is published on the RYA website and build by the Portsmouth Yardstick Advisory Committee. If you like me are interested in statistics it provides fascinating results.
Standard Corrected Handicap (SCH)
The way it works is as follows....
For any given race, there will be an unknown theoretical ‘best possible’ corrected time that could be achieved by a boat sailing perfectly, tacking on the right wind shifts, avoiding adverse currents, etc. In practice boats are not perfect and their crews make mistakes that cause them to sail slower than this optimum. The resultant distribution of corrected times across a fleet will typically be ‘skewed’ since it is easier to make mistakes than to avoid them. A few boats may come close to the theoretical achievable time, some will make an average number of mistakes & there will be a diminishing tail of slower boats making increasing numbers of errors. Performance assessment requires a comparison standard against which to measure each boat. If this standard is simply the average of all corrected times in a skewed distribution, it will be weighted towards the poor performance end and the majority of boats will appear to have sailed better than ‘average’, distorting the assessment. The performance standard is defined instead as the corrected time achieved by the largest group of boats; that is the peak or ‘mode’ of the distribution. Boats that achieved this Standard Corrected Time (SCT) will have sailed ‘to handicap’.
The YR2 procedure allows for the typical 'skewed' distribution in calculating the SCT. The average of corrected times for the top two thirds of the PY, SY & RN boats in the race gives the Average Corrected Time (ACT). ACT+5%, corresponding to the statistically average performer relative to handicap two thirds down the fleet, defines the 'poor performance' limit. The corrected times of all PY, SY & RN boats faster than ACT+5% are then averaged to give the SCT for the race. This new group of boats may be the same as the original two thirds or more or less, depending on the performance distribution in each race. The elapsed time for each boat is divided by the SCT and multiplied by 1000 to give its 'achieved performance'. Corrected times worse than ACT+5% are defined as 'poor' and should be excluded in calculating a boat's average performance for handicap assessment.
PY Handicaps
The handicaps I have used are those published by the RYA. The one assumption I have made in my calculations is that the handicaps of the Wivenhoe Ones are well established and can be included in SCT calculations.
Bostock Cup Results
Handicaps and statistics are very interesting things. The Xenon crossed the finish line second, came 8th out of the club handicaps and 4th in the RYA handicaps (2.3% above par on today's sail).
If you spot any obvious errors let me know.
