Thanks Herman.
···
-----Original Message-----
From: Herman van Beek [mailto:hvanbeek@comcast.net]
Sent: 30 March 2004 14:59
To: Colin Jenkins
Cc: sailwave@yahoogroups.com
Subject: Re: [sailwave] Re: Cox-Sprague
Colin,
The US Sailing Race Management Handbook has this description of "The
Cox-Sprague Scoring System as recommended by the Y.R.A. of Long Island
Sound":
The Cox-Sprague Scoring System
The "Cox-Sprague " scoring system was developed by William S. "Bill" Cox
(New Canaan, CT) and Henry Bancroft "Benny" Sprague (Naples, FL). It is
a curved-line system, and is based on the premise that, for a series,
the scoring system should satisfy at least three conditions:
1. Points for each finishing place should increase or decrease in some
way relative to the variation in the number of starters;
2. The principle of "mathematical weighting" should be built into the
system so that races with more starters will have a greater mathematical
effect upon the series score, and races with fewer starters will have a
lesser mathematical effect upon the series score; and
3. The final step in determining each boat's series score should be to
calculate her "percentage of perfection" (a comparison of actual score
with points which the boat would have scored if she had won every race).
The "percentage-of-perfection" concept is described in more detail below.
The "Cox-Sprague" system takes into account both the number of boats you
beat, and the number of boats that beat you. This can only be
accomplished by using high point systems that are that are adjusted for
a (theoretical) perfect score. Each starter receives the points for her
finishing place indicated in Table 14.1 in the vertical column for the
number of starters in that race. Each boat's "percentage of perfection"
of the final series score is then calculated by dividing her total
points scored by the total points she would have had if she had won
every race in which she started.
In each race each yacht will be credited with the number of points
indicated in the table for its finishing position. The number of
starters will determine which column is to be used for each race. Each
yacht's total score will be divided by the sum of the scores of the
winners of the races in which it starts. The highest resulting score
(percent) wins. Ties in the final standing will be sailed off.
Table 14.1 must be the table you already have for 2 to 20 starters. For
"20 or more" boats, the points for place 13 and higher are (79 - place).
Regards,
Herman
Colin Jenkins wrote:
Bemis says, or at least I think he does, it's a bit vague, that
Cox-Sprague
is "based" on the formula:-
pts = 1311 - 100 * cubedrootof(20*pos + 11)
But there needs to be the number of boats in the race in there
somewhere...!
I think William S. Cox and Henry Bancroft Sprague were involved with the
Star class.
The more I think about scoring the more I think it should be based on 'who
beat who the most'...
CJ
Logarithmic == Austrian == Olympic. Used for Olympics between 1940 and
1960.
-----Original Message-----
From: Ocean Racing Club of Victoria Rudder Cup
[mailto:rudder_cup@orcv.org.au]
Sent: 30 March 2004 11:41
To: sailwave@yahoogroups.com
Subject: [sailwave] Re: Cox-Sprague
I've recently been looking at scoring systems again and found some
notes on Cox-Sprague. The notes are from the forum (I think) in a
post by Geoff Newbury. His stuff quotes a book called "Win More
Sailboat Races" by C. Stanley Ogilvy (WW Norton 1976).
This is the interesting bit:
"Cox-Sprague is not linear, nor quite as non-linear as the Olympic
scoring curve (ORCV - I think this is the Austrian method). More
importantly, the difference in points between boats similarly placed
is the same, whatever the fleet size. What differs is that the
number of points awarded fiffers with fleet size. First always gets
6 points more than second, but first gets 43 in a fleet of four and
100 in a fleet of 20 or more."
So, what this is telling me is that there is a fixed sequence of
differences between the points.
Then the problem is made simpler by only having to work out how many
points first gets - which is a variable dependent on the fleet size.
At this point I can happily hand over to someone else as I don't have
the Cox-Sprague tables to hand - and I have a glass of wine with my
name on it.
Good luck
Ocean Racing Club of Victoria
http://www.orcv.org.au
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____________________________________________________
Herman van Beek email: hvanbeek@comcast.net
2816 Biscayne Drive phone: 972.596.9524
Plano, Texas 75075-7504 fax: 509.692.3503
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