Hi Malcolm
As a past member of the RYA PY Group, I have never heard of the 100 minute rule.
If it is correct, it must have been a factor from many many years ago, before the current statistical method was introduced
Without boring you with detail, the PY system is now based upon recommendations from clubs in the annual return.
The basis of these recommendations ranges from statistical analysis to ‘opinion’ of the club Sailing Committee.
The returns are all fed into a computer & a ‘digest’ produced which shows amongst lots of other data, a three year moving average for each class.
A meeting of ‘wise old men’ - of course I was the youngster of the group 
then review the digest & decide if the number should be changed.
To answer your question therefore, if returns are based upon shorter racing then the current numbers reflect this shorter duration.
However, I am not sure about your basic premise that the accuracy of the PY varies with race duration - surely it is not relevant???
If you are considering what might affect PY, you should be looking in more depth at what your local conditions are.
The RYA PY is for average sailing waters, in average winds, for average sailors.
We all know of boats which are better on the sea than a pond, are quicker in stronger winds, or some classes generally sailed by better sailors.
My advice is to follow YR2 in terms of calculating your own local PYs or if this is too boring, continue to go out & enjoy a good sail, then return to the bar & continue the debate re how all the classes that beat you have the wrong PY;-)
Good sailing
Regards
Ralph
···
From: Malcolm Osborne [mailto:malcolmo@telkomsa.net]
Sent: 22 April 2007 23:37
To: sailwave@yahoogroups.com
Subject: [sailwave] Duration of Races
I have some questions regarding handicap racing - not directly SailWave related.
Portsmouth yardstick is based on races about 100 minutes in duration. We generally sail shorter races these days - more like 50 minutes, the idea being to get in more races per day. Often PY is used for such races, despite the recommendation that it is more accurate for 100 min. races.
Do UK clubs normally sail 100 min. races? Or do they sail 100 minute races only when gathering yardstick data for RYA?
If PY was based on shorter races, would the relative ratings differ materially?
regards,
Malcolm Osborne
Sedgefield, South Africa
