There is a lot of confusion about the difference in the Portsmouth and the Texel handicapping system. Some people seem to think that their boat ratings are very different and that the Order of Finish of a race would always change if the other was used.
Some people believe in the Texel system because it is strictly a mathematical formula which does not consider “on the water” results, but this is not correct. In October , 2001 Texel “adjusted” the formula for single-handed boats because REAL WORLD RESULTS had shown that singles were not finishing high enough in handicap races. Some adjustments were made in March 2002 also.
Some people believe that the Portsmouth number is a guesstimate which changes radically every time races are reported. This is not correct either. As numbers are reported they are added to the database and help to refine the number.
These two handicap systems simply use a multiplier to arrive at an adjusted elapsed time. Assuming two perfectly accurate, linear rating systems, if boat A is rated 10% faster than boat B in one system, it should be 10% faster in another system. Therefore the ratio of one system HC multiplier to another, should be a constant.
In an attempt to compare the relative accuracy of the two systems, I decided to compare the ratio of the Texel number to the dPN (Texel/dPN) of all the cats I could find which were apparently identical in the US and EU and had been sailed enough in the US to get a valid dPN. The lower the ratio, the bigger the advantage for a given boat to sail under Portsmouth instead of Texel.
This would hopefully provide a multiplier that could be used to convert a Texel rating to a Portsmouth handicap and vice-versa.
11 Single handed boats
1.52 - Dart 18(1), Prindle 15s, Supercat 15
1.53 - A-class
1.54 - Hobie 14u
1.55 - Nacra Inter 17R
1.56 - Nacra 5.5 uni, Paper Tiger, Seaspray 15
1.57 - Nacra Inter 17, Hobie 17u
1.54545 average
Anomalies not used for calculations:
1.44 - Nacra 450
1.45 - Formula 16hp (Taipan 4.9 w/spi. modification)
1.47 - Hobie 14s, Taipan 4.9 unirig
29 Double-handed boats:
1.52 - G-cat 5.0, Prindle 18, Trac 16
1.53 - Formula 16hp, Hobie 18, Nacra 5.0, Nacra 5.2, Trac 18
1.54 - Dart 18(2), Hobie 16, Mystere 6.0, Nacra 5.8, Nacra 6.0, Prindle 16, Tornado Sport
1.55 - Mystere 5.5, Nacra 5.5 sl, Prindle 18-2, Prindle 19, Shearwater, Supercat 19
1.56 - Hobie 20, Nacra 6.0se, Taipan 4.9
1.57 - Formula 18HT, iFormula18, Supercat 20
1.58 - Tornado classic, Ventilo 20
1.54621 average
Anomalies not used:
1.39 – Shark
1.45 - Nacra 570
1.70 - Tapan 5.7 w/spi.
Composite average (uni and double): 1.5458
Summary:
The numbers and their results turned out much closer than I had expected. With the exception of the various anomalies, the range and average for the two categories was almost identical. The anonomalies were either very old boats which were no longer raced by the “hard core” but still made it to a few races, or new boats which had aparently been given an erroneous dPN in the beginning.
The smaller, older, less raced boats generally made up the low end of the two groups. They are usually raced by the more casual sailor in a less than pristine condition (sails, rigging, etc.). This would very slowly drive down the dPN.
The high end of the ratios was generally the bigger, more high tech boats that are usually raced by the hard core. I would expect those boats to be in serious racing tune.
The center of the unis was anchored by the Hobie 14, the most widely sailed and raced uni in NA. The Hobie 16 is squarely in the middle of the doubles.
Conclusions:
The concept of a single value, 1.5458, which can be used to convert a Texel rating to a dPN number, or vice-versa, appears valid.
This study shows the weaknesses of the Portsmouth system when a boat is either very new or very old. These flaws can be to the skippers advantage, such as the Shark or Taipan 4.9 or disadvantage, such as the Taipan 5.7. Racing under Portsmouth, in a one hour race, a uni Taipan 4.9 w/spi sailor would get a five minute “head start” over the Hobie 17, compared to Texel. That explains some of this years results. A Taipan 5.7 w/spi. sailor would give the average boat (1.546) a five minute head start. No wonder Rick is selling his.
This study also shows that the Portsmouth system, with enough data, is as accurate as the Texel system for establishing a handicap baseline.
I hope this will encourage people to forward their HC race results to Darlene at US Sailing so she can keep the numbers as accurate as possible.
P.S.
Anybody got a good Shark for sale? I might be able to win some races with one of those.
