No changes to the formula this year, but once again we have done a thorough statistical review which is published in the Downloads section of the website. It is vital to keep monitoring race results to see that the formula is working properly.
SCHRS is taking a positive approach to the coming year and looking forward to a growing number of events in the sailing calender. We have re-formed both the World Council and Technical Committee around the most active members. And we welcome Yorick Klipfel from Switzerland to strengthen our technical committee.
We have also been through a full statistical review of results to check the formula is working correctly.
Finally we have made one change to the formula: we have sharpened the spinnaker penalty which will make non-spinnaker catamarans very slightly more competitive. We will continue to keep this under review, and may make further changes in the same direction in future years.
The 2020 SCHRS numbers will remain in place for 2021. Due to regatta cancellations we have no further data to analyse and no further problems to address.
Progress has been made in one important area. On 1st July 2020 SCHRS signed a Protocol d'Accord with the FFV (Federation Fancaise de Voile) which regularised our use of their excellent performance database. Within the framework of this agreement, the FFVoile makes available to the SCHRS, on the basis of an appropriate and automated exchange format, all the data intended to feed the SCHRS statistical software. This will have the great advantage of saving us considerable time in collecting data and securing our sources. This agreement is subject to confidentiality and non-competition rules which preserve the interests of both parties in a balanced manner.
We also continue to collaborate with the UK's RYA (Royal Yachting Association). The relationship with SCHRS enhances the scope of the RYA's Portsmouth Numbers system: PN can only include the 10 catamaran classes for which there is sufficient performance data, but the SCHRS formula can safely extend this to some 250 catamaran classes and variants.
The 2020 Round Texel race was cancelled so our cordial collaboration with the Dutch Texel Committee has missed a year. We hope to meet in 2021, continuing to use the same core formula and to compare notes on the detailed adjustments.
Collaboration with other authorities is more important than ever during a period of lockdowns. More racing is done using handicaps at club level because sailors can travel less. The handicaps within the catamaran world are optimised by SCHRS: and the handicap relationships between catamarans and monohulls, which will never be perfect, are supported by the statistical work done by the RYA’s PN committee. We are always looking for more usable data to support the formula.
We have one change to the formula for 2020: we have increased the spinnaker penalty from .11 to .12, thus improving the rating of non spinnaker boats. For more details, please refer to the downloadable 2020 Review paper.
This year we are trying to improve the way data is made available to race organisers. We have therefore included the data, in CSV format, on our downloads page.
We try to only update the data once a year - very occasionally an obvious error is corrected mid season. The idea is that users need only download once a year, preferably just after our adjustments are published in late January.
We have also clarified the terms on which our data is used - see the terms and conditions page of the updated website. Our main concern is that there is only one set of SCHRS figures in circulation - to achieve this we need to assert ownership of our formula and data. If you want to use the data in a non-standard way please contact us.
This year we are replacing the LTM penalty for square top mainsails with a simpler 0,1,2 system. For more details, please refer to the downloadable 2019 Review paper.
Updated the site for 2018 including the Calculator, Rating Request forms, Annual Review and the Ratings for 2018, please refer to the in the downloadable 2018 Review paper.
In 2017 we simplified the core formula to:
1.111 x W0.3
L0.325 x A0.41
where W is all up sailing weight, L is length and A is sail area. This has had little effect on the ratings but makes the formula easier to manage, the details are explained further in the downloadable 2017 Review paper.
The 2016 review includes a major overhaul of the data. Wherever possible it is now in line with class rules. It also includes some minor changes to the formula which are explained in the downloadable 2016 Review paper.
Inclusion of a Downloads page, replacing the original "Calculator" link and page. This now inlcudes the latest Calculator, Individual rating request form and the latest World Council review paper.
The SCHRS ratings have been reviewed for 2015. A full description of the changes are given in the downloadable downloadable 2015 Review paper.
The appointment of Jean-Claude Rouves as Chairman of SCHRS has been approved.
Nick Dewhirst Chairman of the World Council of SCHRS sadly died in July 2013. This was a great loss to the world of catamarans where his experience and his persuasive quality were appreciated by all.
Following extensive discussions the Committee has appointed M. Jean-Claude Rouves as its new Chairman. According to the constitution we have applied for ratification from the World Sailing Equipment Committee, something that we expect to receive shortly.
The SCHRS ratings have been reviewed for 2014. A full description of the changes are given in the downloadable 2014 Review paper. Included are some provisional ratings for some foiling boats. So far data on the performance of these boats is scarce, and it may be necessary to review the figures during the season.
Amended ratings for Nacra 16 and Nacra 17 following receipt of measurement data for production boats. Previous ratings were based on measurements on the prototypes.
Correction to Sprint 15 DX, re-instatement of the application of the Rated Length adjustment.
Additional data for Formula 16 classes added at the request of the International Formula 16 Association.
2013 Formula updates
Minor changes to the formula approved by the World Council for the 2013 sailing season including:
- Adjustment to the crew weight assumption to recognise that smaller catamarans can be sailed by lighter people
- Softening of the board correction penalty for long boards
- Introduction of a formula for gennakers - headsails that can't be used upwind, but breach the 75% SMG/SF limit
- Minor adjustment to the power factor calculation
- Jib area diagram changed to conform with the method used by Texel
A full description of the changes are given in the downloadable 2013 Review paper.
Hurricane 5.9 update
Review of Hurricane variants in the UK, incorporating up to date weights and the square top mains on the Hurricane SX.
2012 Formula updates
Formula changed to address anomalies raised by the FFV, the Texel rating team and the F16 class. A full description of the issues and changes are given in the downloadable 2012 Review paper.
Revised Board Correction
A new board correction (BC) formulation has been created to fix an anomaly in the previous formula, which has only become a problem now that very high aspect ratio boards are being used on some boats. The previous BC correction started reducing again for a board aspect ratio greater than 5, due to its quadratic nature. The new formulation is asymptotic such that it continues to increase and tend toward a final value for very high aspect ratio boards. The new formulation has very little effect except for boards with aspect ratios of 5 or more. The proposed formula is BC=15-15/(XB^0.1045)+2. XB is the aspect ratio of the board, there is no penalty for larger boards, just for the aspect ratio, which reflects efficiency.
A new method for measuring the length of the board (VLB) has been created this will give a very small penalty for curved boards, where depth will be measured around the circumference. It will also give a small penalty for T foils, as the length of the horizontal section will be included in VLB. This is an interim measure. A full review will be needed when and if curved boards and T foils start to show a significant and consistent advantage.