Vic Trailable Yacht Division Recommends 'Old' CBH

Published Tue 26 Sep 2023

For season 2023-2024 the Victorian Trailable Yacht Division (V-TYD) of Australian Sailing does not recommend the adoption of the ‘New’ Australian Sailing CBH System in the state of Victoria. It is recommended that clubs/associations continue to use the ‘Old’ CBH ratings.

As per the “Australian Class Based Handicap (CBH) Rating System” the use of the new CBH system is recommended, however clubs/associations and other organising authorities can run racing under any system they feel appropriate.

The primary reason for this is that the V-TYD believes that the new system will hinder rates of participation in the state of Victoria. The drivers for this recommendation are outlined below:

  • The vast majority (~95%) of the Victorian trailable yacht fleet sails in class standard configuration
  • For class standard trailable yachts, the old CBH system has been performance adjusted using over 30 years of race results, meaning in 95% of cases it was a very reliable system
    • In Victoria we have found that under the old CBH system the best crews sailing the best prepared boats won consistently, irrespective of class
  • There are approximately 50 classes of trailable yachts and OAKs that do not have a rating under the new CBH system
  • The V-TYD understands that the new CBH and the old CBH ratings do not correlate and should not be used in side-by-side comparison, however when comparing rating shift between systems:
    • Some classes have seen a CBH reduction of -6.2% (Austral Clubman 8)
    • Some classes have seen a CBH increase of +19.4% (Hartley 21)
    • This means there is up to 25.6% competitive difference between classes under the new system, which equates to wholesale change in ratings and results
    • The median CBH change between systems is +3.7%
    • The mean CBH change between systems is +5.0%
  • The numbers above suggest that either the new CBH system has either:
    • Incomplete or poor-quality input data to allow for the reliable calculation of trailable yacht CBH ratings, or;
    • The mathematical solution of the formula is not refined enough to accurately rate trailable yachts fairly
      • From initial analysis heavier, more powerful boats, appear to be at a rating advantage with weight in general appearing to be a very sensitive input
  • Australian Sailing do not appear to have a feedback mechanism through which to refine the formula or correct erroneous inputs with owners and/or associations being left to fend for themselves with little to no guidance

Whilst we acknowledge the good intent of the new CBH Ratings, from the outset the V-TYD has been consistent in its position that when we requested a review of the old CBH system. Primary messages from V-TYD to AS were:

  • Wholesale change of existing CBH ratings was not required as they were proven and working well for Victorian races
  • The ability to fairly rate one-of-a-kind and new trailable yachts, without necessarily rewarding them was required
  • The new system should make the rule more inclusive and lower the barrier to entry for sailors of one-of-a-kind, new designs, or existing designs that didn’t meet in part the Australian Trailable Yacht and Sports Boat Rule
  • The new system must lead to increased levels of participation

It is the V-TYD’s preferred position that we are in step with AS and the CBH system, but it seems that the needs of Victorian Trailable racers must differ from other states. Through a deep understanding of our community and stakeholders through a wide cross section of clubs and associations being part of the V-TYD, we believe adopting the new CBH rating system will be detrimental to participation.

Finally, it is acknowledged by the V-TYD that the sports boat community has a long history of performance optimisation, modification, and one-of-a-kind build boats. We believe the new CBH system is suitable for these boats and have encouraged Victorian sports boat sailors to adopt.

For reference a copy of the 2019 Australian Trailable Yacht and Sports Boat Rule ratings are attached.

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