Hi - I'm new to the group and new to Sailwave also. I think I have it
somewhat figured out but I cannot seem to make sense of the numbers used for wind
indexing ie: the 650 and 550 numbers that are"popular". Do they corelate to
anything real? Also, the numbers 0-1, 2-3, 4, 5-8 etc. Are those supposed to be
wind strengths? The FAQ's say they can be substituted with "gentle, medium"
etc. If you use descriptions rather than actual wind strengths how do you
know what they corelate too?
We are using TOTPHRF and I'd like to be able to adjust for wind strength but
these numbers seem to be completely arbitrary.
Thanks in advance for any help you guys/girls can offer.
Paul
[Non-text portions of this message have been removed]
Hi Paul,
Hi - I'm new to the group and new to Sailwave also. I think I have it
somewhat figured out but I cannot seem to make sense of the
numbers used for wind
indexing ie: the 650 and 550 numbers that are"popular". Do they
corelate to
anything real? Also, the numbers 0-1, 2-3, 4, 5-8 etc. Are
those supposed to be
wind strengths? The FAQ's say they can be substituted with
"gentle, medium"
etc. If you use descriptions rather than actual wind strengths
how do you
know what they corelate too?
Say your wind strengths are A, B, C, D and your wind indexed handicap values
for a particular class are 100,101,102,103. If you log a wind stregth of C
in a race (start), the handicap value used will be 102. So the descriptive
wind sthrengths can be anything and are just used to find the appropriate
handicap value. An associative index.
We are using TOTPHRF and I'd like to be able to adjust for wind
strength but
these numbers seem to be completely arbitrary.
I don't really know anything about PHRF!, I just looked on the USSA web site
and implemented what I saw. There may be a description of what the numbers
men there... Or perhaps somebody else can exaplins... You can seup you
wind indexed A and B values in the same way as setting up wind indexed
handicap values.
Regards,
Colin J
www.sailwave.com
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The numbers that you refer to in your note "the numbers 0-1, 2-3, 4, 5-8 etc" are references to the Beaufort scale developed in in 1805 by Admiral, Sir Francis Beaufort of England. The Beaufort wind force scale is often thought to be a simple numerical relationship to wind speed based on an observation of the effects of the wind. However it orginal was originally devised to describe the effect of the wind on an 18th-century fighting ship. The Beaufort scale intends that you look at the ship not at the wind. The descriptions for Beaufort numbers 0 through 4 describe the wind in terms of the speed that it may propel the ship; those for 5 through 9 in terms of her mission and her sail carrying ability; and those for 10 through 12 in terms of her survival.
In 1912 the International Commission for Weather Telegraphy sought some agreement on velocity equivalents for the Beaufort scale. A uniform set of equivalents was accepted in 1926 and revised slightly in 1946. By 1955, wind velocities in knots replaced Beaufort numbers on weather maps. But there were still a need for eyeball estimates by seamen to fill the gaps in the global observing network. Thus it became that the Beaufort number was estimated by observing the effects of the wind.
Mark Townsend
s_mark_townsend@hotmail.com
----Original Message Follows----
···
From: pwestla@aol.com
Reply-To: sailwave@yahoogroups.com
To: sailwave@yahoogroups.com
Subject: [sailwave] Wind Index Numbers
Date: Thu, 12 May 2005 13:42:03 EDT
Hi - I'm new to the group and new to Sailwave also. I think I have it
somewhat figured out but I cannot seem to make sense of the numbers used for wind
indexing ie: the 650 and 550 numbers that are"popular". Do they corelate to
anything real? Also, the numbers 0-1, 2-3, 4, 5-8 etc. Are those supposed to be
wind strengths? The FAQ's say they can be substituted with "gentle, medium"
etc. If you use descriptions rather than actual wind strengths how do you
know what they corelate too?
We are using TOTPHRF and I'd like to be able to adjust for wind strength but
these numbers seem to be completely arbitrary.
Thanks in advance for any help you guys/girls can offer.
Paul
[Non-text portions of this message have been removed]