Sail Race Management - Cruiser Phrf and RYA PN correlation
Whilst boat handicapping is only a small part of Sail Race Management, the topic is often the least understood and raises many emotive responses from competitors.
With limited race data available it is very dificult to differentiate between crew and boat performance. Statistically relevant data can be readily gathered for dinghies and 'one design' fleets, however, the range of cruiser types and configurations does create some difficulties. Setting a handicap for an unfamiliar/new boat type without an RYA PN, not using established marine ratio data, adjusting on subsequent races in the prescribed manner, can very easily produce anomalous values until sufficient time has elapsed to enable the RYA to gather and publish definitive data.
The objective is to use scientifically based mathematical
relationships to economically allocate initial boat handicaps
for clubs in an attempt to keep the peace and assure fair play.
Handicap calculation routines are based on the Phrf regression formula
and curve matching to RYA primary/secondary and recorded number
cruiser values, that's PY,SY and RN.
Calculations are offerred free on completion of Phrf
/ PN handicap data sheet.
The regression formula for predicting Phrf ratings from basic hull and rig specifications was developed by Terry "stats-man" Schell (and his university colleagues in the USA) from over 500 boats and their race results. The formula is in current use for 'base' calculations for several major Sailing Organisations in the USA. Thanks Terry for all your excellent work and allowing your research to be used here.
The following indicates the degree of correlation between RHN and established RYA PN handicaps accross the normal range. Calculations are based on 'Displacement Sailing' which would account for certain discrepancies when a boat can exceed its Lwl speed.
Please Note - Clubs may need to adjust a PN/RHN when allocating a club handicap to suit local conditions, of course reasons should be declared. RYA traditional abreviations and variation allowances are used, RHN includes the use of 'standard' spinnaker. Greater confidence is achieved in an RHN value when definitive rig data is available.
Updated: 07/29/04
| PN | Class | RHN | SA/D | Knots | Disp | Lwl | Beam | Draft | SA | I: | J: | K: | P: | E: | |||||
| 994 | Contessa 32 (py) | f | ib2 | 992 | 20.05 | 6.56 | 9500 | 24 | 9.5 | 5.5 | 562 | 37.2 | 12.67 | 18 | 35 | 10 | |||
| 1008 | Hunter F1 (tn) | f | ob | 1008 | 28.26 | 6.03 | 2027 | 20.24 | 7.81 | 4.73 | 24.12 | 7.38 | 11.02 | 27.3 | 10.99 | ||||
| 943 | Hunter Impala (py) | f | ob | 944 | 23.98 | 6.44 | 5554 | 23.08 | 9.17 | 5.58 | 470 | 35 | 10.42 | 14.6 | 37.42 | 11.52 | |||
| 1038 | Hunter Sonata (py) | f | ob | 1038 | 22.31 | 6.17 | 2458 | 21.2 | 8.5 | 4.5 | 23.7 | 8 | 12 | 26.3 | 8.5 | ||||
| 936 | J24 (py) | b | ob | 939 | 27.84 | 5.99 | 3100 | 20 | 8.92 | 4 | 370 | 26.25 | 9.5 | 15.8 | 33 | 9.75 | |||
| 1060 | Sadler 25 (py) | f | ibf | 1063 | 21.13 | 5.87 | 4500 | 19.17 | 8.75 | 4.67 | 360 | 31 | 9.9 | 16 | 25 | 8.5 | |||
| 924 | Sigma 33 (py) | f | ibf | 924 | 21.86 | 6.87 | 9200 | 26.25 | 10.5 | 5.75 | 600 | 37 | 11.75 | 16.7 | 45 | 13 | |||
| 1207 | West Centaur (py) | 2k | ib3 | 1205 | 14.09 | 6.18 | 6700 | 21.3 | 8.4 | 3 | 32.33 | 10.08 | 7 | 34.75 | 11.5 | ||||
| 1014 | West GK 24 (py) | f | ob | 1014 | 20.73 | 6.17 | 1875 | 6.46 | 2.85 | 1.52 | 31 | 8.55 | 2.59 | 3.9 | 9.45 | 3.05 | |||
| 1022 | West GK 24 (py) | f | ibf | 1024 | 20.73 | 6.17 | 1875 | 6.46 | 2.85 | 1.52 | 31 | 8.55 | 2.59 | 3.9 | 9.45 | 3.05 |
Updated: 08/03/2007
The computer handicap calculation routine has been adjusted by 0.1% for 2007 as a result of a comparison exercise against all RYA Primary/Secondary and Recorded number boats (as there are only four 2007 PY boats, this category alone is not statistically relevant, so we needed the larger sample to provide better accuracy for the average sailor and boat), aditional weighting was given to SY boats which statistically have better club handicap returns. The results of this comparison are to be added to this page in due course, ie when time permits, but at least you can follow the link for the updated boat PNs now.
For updated numbers and an
increased number of boats with 2007 handicaps, please
select link Here