KW scoring analysis

The latest version of the Rule Calculator is HPR V4f1 (a small correction of V4f), and is posted now online by clicking here: HPR Calculator V4f1.xls. This version has even more improvements on V4e based on an analysis of results from the fleet at Quantum Key West, as well as several other factors summarized below.

The following gives an overview of the recent evolution of the V4 rule calculators:

Changes in Rule Calculator V4d (Jan 2013)

Prior to Key West Race Week, the following changes were been made to the Rule Calculator creating version V4d:

* The penalty bowls for Beam, Freeboard, Draft, VCG, Crew Factor, and Displacement were replaced with increased slopes, mostly 2X and 4X.

* The slope of the beam performance line was changed to rate beam solely on crew arm with the exception of a very small component for windage.

* The point at which existing boats no longer receive displacement credit has been increased from 20% to 30% of base displacement.

* IG has been increased from a maximum of 0.88 of P+BAS to a maximum of 0.92.

* The requirement to use luff-based mainsail widths for calculating mainsail area has been delayed for one year.

Changes in Rule Calculator Version V4e (mid Feb 2013):

* Removes freeboard penalty for low values on existing boats.

* Re-calibrates the displacement slope using a heavier boat.

* Increases propeller credit for existing boats to the calculated amount.

* Adjusts the TOT curve to give more credit to smaller boats relative to larger ones.

* Increases the age allowance for all boats with an age or series date of 2011 or earlier by 1% of rated length. This is a bonus increase overlaid on top of the existing 0.2% per year of age allowance.

* Qualifies existing production boats for the Economy of Scale credit.

* Provides a penalty for bowsprits whose length exceeds the HPR maximum of 0.4229*L+2.285m as follows: 4 times the excess length shall be added to the asymmetrical spinnaker width in calculating the spinnaker area. 

Changes in Rule Calculator Version V4f (late Feb 2013):

* Additional old age credit given to pre-HPR designs, with large step function from 2011 to 2012, and progressing about 0.2% each year prior to 2011.

Here is a summary of rating changes using V4f for some recently-raced HPR boats, expressed as % change in TCF and in rated sec/mi:

OOAH Flying Jenny Interlodge Spookie Stray Dog Catapult Santa
MC 38 TP 52 IRC 52 Carkeek 40 GP 42 Ker 40 Farr 400
-2.8% TCF +0.8% TCF +0.2% TCF 0.0% -1.9% TCF

-2.0% TCF

-2.1% TCF
+16.8 sec/mi +3.5 sec/mi +0.7 sec/mi 0.0 +10.8 sec/mi +11.6 sec/mi +12.9 sec/mi

Comments on these changes are welcome: please contact Bill Lee at This email address is being protected from spambots. You need JavaScript enabled to view it..

V4f will be used in the upcoming HPR40 Midwinter Regatta in Miami over 5-9 March, with new certificates issued for entries to this event.

Also, please note that while the V4f Calculator is now ready, the HPR Rule book is still under revision to reflect these latest changes.

All previous versions will be deleted from the HPR website so as not to cause confusion with this latest version.