RYA Portsmouth Yardstick Scheme

Club Racing at YDSC includes many different craft, so we need to use a Handicap System.

Several decades ago, the RYA adopted a scheme to allow boats of different classes to race ‘on handicap’ against each other and that scheme is still used today. It’s based on Portsmouth Numbers (PNs) where every boat is assigned a PN based on its comparative performance. So if a boat with a PN of 1000 takes 1000 seconds to complete a course, then a boat with a PN of 1200 should take 1200 seconds.

Handicap racing is never fair in the same way as class racing can be. What the RYA and the club are striving to achieve is the fairest system possible so that sailors of equal talent have a reasonably equal chance of winning over a series in any class.

The RYA publishes updated National PNs (NPN) annually through the Portsmouth Yardstick Scheme together with a method for amending handicaps to suit the conditions and type of racing of a particular club.

Clubs have always been asked to calculate, use, and then return these amended handicaps to the RYA. Those re-worked numbers were then consolidated into the update for the following year. However these returns were difficult to calculate and returns to the RYA have historically been sparse. In fact the vast majority of clubs made no return or made zero changes even though it was generally accepted changes were needed. This made the data UNRELIABLE. As a result there was virtually no movement of handicaps for year after year. An entirely unsatisfactory situation that led to some classes having extremely challenging handicaps while others were very advantageous.

In 2012 the RYA provided an on line system through which clubs can return their actual race data for the RYA to include directly in their analysis and YDSC participates in this.

There are several reasons why using the ‘standard’ RYA PN handicaps is unsatisfactory and why the RYA recommends the use of ‘Club Specific’ PNs including:

  • The RYA PN handicaps are an average of often UNRELIABLE data returns from all venue types including rivers, gravel pits, tidal waters and lots of small lakes but very few large Inland water sites. Being numerically biased towards small lakes etc., they do not properly reflect conditions at Grimwith.
  • The wind is often stronger and much steadier than at 90% of other venues – making YDSC an almost unique venue – not at all comparable to most smaller lakes and gravel pits etc.
  • It’s long been recognised that for some Development classes there is a massive lag between any increase in performance and the necessary change in National PN – potentially giving them an unfair advantage
  • New classes are often recommended a generous handicap by the manufacturer or class association, (not the RYA), as it is usually in their interest to get the class noticed through results – albeit unfairly gained.
The RYA recommended handicapping method at YDSC

Race data from our various handicap series has been input to the RYA website and their systems have analysed the data – producing recommended PNs for YDSC.

Basically, they compute the average corrected time for a race and then for each class within it. This shows what change in each class handicap would be needed for their average corrected times to all be the same. Only the front / middle performers are used and the others are automatically excluded before class handicaps are computed by the RYA. That’s intended to prevent undue influence from those who were late to the start, having a really bad day or simply new to the sport or the boat. So to expand on that:

  • Only the top 66% of finishers are used + Of the top 66% only those that finish within 105% of the standard mean corrected time are counted

Movements in class handicaps are weighted so that as the number of results for any class reduces so the small amounts of data do not have an undue influence.

After inputting all the data available, for all the series over nearly 5 years, the RYA system has produced a list of Yorkshire Dales specific Portsmouth Numbers – for all those classes with sufficient data available.

They also give a confidence level. ‘Confidence’ refers to the stability of the number – not its accuracy.

Confidence in the stability of PNs clearly rises as more race data is input. We decided to recognise the likelihood of increasing confidence over time, and so the Sailing Committee has agreed that the changes recommended by the RYA for YDSC will be implemented in full for the most stable Numbers / classes. However where confidence in stability is reduced or very low we will ‘moderate’ by applying % adjustments – decreasing the % of Club PN and increasing the % of NPN and/or GL as confidence reduces.

Depending on the confidence level, the % of any change applied will be as shown below. The table shows calculations for PN based on data and degree of ‘Confidence’

Confidence (max 1) CLUB % NPN % GL %
0.75 > 100
0.5 > 75 25
0.25 > 50 50
up to 0.24 25 50 25
0 75 25

This is designed to reflect the degree of confidence that the data is a reliable and stable indication of relative performance of the various classes at the club.

Other factors and data used

Yorkshire Dales is part of a grouping of clubs based on larger lakes such as Queen Mary, Grafham, Rutland, Northampton, Draycote, etc. known as The Great Lakes Group. For classes where there are currently no boats at YDSC and hence no data, we (partially) include the PN numbers produced using data from these big clubs (The Great Lakes numbers). The experience of the relative performance for the classes that we do have in decent numbers is fairly similar and so the GL numbers are a useful additional ‘damping factor’ to ensure we use good data from the best available source.

For any brand new classes a cautious approach will be taken to handicap assignment. Get it wrong and one sailor may be happy but 100 will not be. Class provided handicaps are likely to be reduced by a sufficient factor to make it challenging for new classes to get into the prizes in their first season. Once we have race data from our own experience and from other venues, then the handicap will be adjusted in subsequent years.

Club class handicaps are usually adjusted annually based on adding the completed season’s results to the existing data and running it all through the RYA analysis site. They are then reviewed again before the new season to include any national PN handicap adjustments. These handicaps are then used for Club handicap racing.

The Sailing Committee is responsible for the handicap review and application of RYA recommended adjustments.

The New PN numbers for YDSC are here.

Do feel free to ask for more information and let the committee know how you think the race handicapping is working.