Art,
The problem is that handicaps of one system are used in another one.
Handicaps for PHRF are related to a virtual reference boat, and are showing how many seconds per mile a boat is faster or slower.
Handicaps of ORC Club (normally NOT used as ToD except at club level) are expressed in seconds per mile. Then you can use the PHRF formula if you define a reference boat, and the size of the reference boat has NO EFFECT on the final result..
There may be two different questions:
* the fleet is mixed PHRF / ORC Club
* the fleet is ORC Club only (this is the case in Cyprus)
In the first case, you should use the conversion formulas as proposed.
In the second one, you can use PHRF with any reference boat size. Corrected times expressed as + or - are no race times. If you choose any value for the reference boat, the results will be obvious.
Even if this is of little use, the calculation of IMS / ORC Club regattas on GHP ToD is almost the same as PHRF, you have just to define the reference boat, or let the system choose one...
Anyway, the fact that SW doesn't rank properly when there are negative values should be corrected...
Phil
···
----- Original Message ----- From: "Art Engel" <artengel123@earthlink.net>
To: <sailwave@yahoogroups.com>
Sent: Sunday, March 28, 2010 11:54 PM
Subject: Re: [sailwave] Re: problems in scoring offshore races
I think you may have missed the point of the discussion. Both PHRF and
ORC Club use Time on Distance type scoring. Sailwave apparently cannot
score ORC Club although it can score PHRF.The reason is that PHRF ToD scoring is standard - like IRC and every
other rating system I've ever heard of. It converts everyone's time into
an equivalent time for some base boat. So if the average boats sail the
course in 1 hour everyone's time will be converted to look like a boat
that would typically sail the course in say 50 minutes. In other words,
if you sail around the course at the speed predicted for your boat
(which is say one hour) then your corrected time will be say 50 minutes.ORC Club is different and unique. If you sail around the course in the
speed predicted for your boat then your corrected "time" will be zero
(00:00:00). That means about half the boats should have negative
corrected time. In the real world we would describe that as time travel
- finishing a race before you have started it!I wouldn't try to actually and really "convert" ORC ratings into PHRF
ratings as that is a subtle and sophisticated process. Instead, I would
treat ORC Club ratings like PHRF ratings for scoring only and then score
using Sailwave's PHRF ToD scoring. The way to do that is subtract some
constant number from every GPH, say 600. Then every boat will have a
positive corrected time that is close at least close to the actual time
for the race.Art Los Angeles
PS - I am guessing that ORC ToD was developed by some marketing people
who don't actually sail as the concept of negative corrected times will
NOT be understood by the sailors.phinnros wrote:
I may be way off here but there seems to be a lot of discussion that is interchanging PHRF and ORC. They are 2 different handicap systems. If one is using PHRF use the conversion formulas to get a PHRF rating and then score using PHRF.
Here is a link to the conversion formula at PHRFNE
http://www.phrfne.org/page/570Ross
RKYC Saint John--- In sailwave@yahoogroups.com, Huw Pearce <huw.pearce@...> wrote:
Yiannis & Jamie,
Caveat to the following - this is the first time I have looked at ToD
handicapping, so I may be completely of beam. Apologies in advance if so.I have had a look at the ORC web site (www.orc.org) and the rating
values look plausible (http://www.orc.org/clubcert.htm). I also followed
the link (http://www.orc.org/clubscoring.htm) to their scoring options
and using the information on their web site the calculations Sailwave is
doing appear correct. The ORC web site does not say in what units the
distance is measured, but are they nautical miles or statute miles! I
would assume nautical.What Sailwave seems to be doing when sorting corrected times is taking
the value of the corrected time ignoring any plus (+) or minus (-) sign.
I would have expected that all corrected times would be a positive value
and therefore no problem with sorting on corrected times, but when
negative times occur it has highlighted a boundary condition that was
possibly not anticipated.------------------------------------
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