It's been a couple years since I used Sailwave.
How do I get it to score races as "Time on Time" -- I kind of remember I have to go to some "advanced settings" or something like that.
Click on the upper bar “setup”, click “scoring system” in the drop down box, which then opens a box, click the “rating system” tab with in the box, and you can choose the rating system, TOT PHRF is the 8th one down. You will also need your A and B numbers to fill in a box just to the right. Hit “OK” at the bottom and you are finished.
Marty
···
To: sailwave@yahoogroups.com
From: jeffblundell@rogers.com
Date: Sat, 14 Aug 2010 22:05:35 +0000
Subject: [sailwave] scoring Time on Time with PHRF
It’s been a couple years since I used Sailwave.
How do I get it to score races as “Time on Time” – I kind of remember I have to go to some “advanced settings” or something like that.
The Sailwave user guide at http://www.abyc.org/upload/Sailwave_ABYC_User_Guide.pdf
provides an explanation of how to use PHRF TOT on page 60, which is attached below.
How Do I Use PHRF Time-On-Time (TOT)?
Select PHRF (TOT) as the rating system from the Rating System tab of the Scoring System window (Edit+ScoringSystem).
Sailwave uses a conversion formula to convert the standard PHRF TOD handicap into a PHRF TOT Time Correction Factor (TCF). The formula used is:-
A
TCF = ------------------
B + PHRF
Sailwave allows you to enter the values for A and B. For example 650 and 550 are popular.
There are no hard and fast rules for selecting the B coefficient. Basically, the lower you select it, the more favorable it will be to the slower boats. The denominator, B + PHRF, can be the number of seconds it takes to sail a nautical mile in the expected conditions. Another way to look at it is that the denominator divided into 3600 is the average rhumb line boat speed in knots. If you have not been provided with a B factor by the Organizing Authority or wish to set your own, do some testing with previous race results to make sure that the number you select provides reasonable looking results.
Several clubs in Southern California use a Time Correction Factor of 650 / (625 + PHRF), this was tested against previous results and was found to provide the fairest TCF given the SoCal PHRF ratings and the mix of boats that were being handicapped.
US Sailing suggests using the following B factors:
** B Factor **
** When Used**
480
** Heavy Air or all off the wind**
550
** Average conditions**
600
** Light air or all windward work **
The numerator, A, is merely a coefficient that makes a nice looking TCF. Select it so that the TCF for the middle of the fleet is about 1.000. The A coefficient has absolutely no effect on the corrected finish order. Changing it will only affect the various margins. Thus if your middle handicap is about 100 and your conditions are average, then the TCF formula would look like the following:
TCF = 650 / (550 + PHRF Rating)
To calculate the corrected time, Sailwave multiplies the elapsed time by the TCF.
TOT scoring usually does not affect the top boats. It usually moves the boats in the middle around a little. If the handicap spread in a class is large, it will tend to tighten things up a bit.
Mark Townsend
s_mark_townsend@hotmail.com
···
From: jeffblundell@rogers.com
Sent: Saturday, August 14, 2010 3:05 PM
Subject: [sailwave] scoring Time on Time with PHRF
It’s been a couple years since I used Sailwave.
How do I get it to score races as “Time on Time” – I kind of remember I have to go to some “advanced settings” or something like that.
Thanks Mark.
Jeff Blundell
FBYC
···
----- Original Message -----
From:
S. Mark Townsend
Sent: Sunday, August 15, 2010 12:12 PM
Subject: Re: [sailwave] scoring Time on Time with PHRF
The Sailwave user guide at http://www.abyc.org/upload/Sailwave_ABYC_User_Guide.pdf
provides an explanation of how to use PHRF TOT on page 60, which is attached below.
How Do I Use PHRF Time-On-Time (TOT)?
Select PHRF (TOT) as the rating system from the ** Rating System** tab of the Scoring System window (Edit+ScoringSystem).
Sailwave uses a conversion formula to convert the standard PHRF TOD handicap into a PHRF TOT Time Correction Factor (TCF). The formula used is:-
A TCF = ------------------ B + PHRF
Sailwave allows you to enter the values for A and B. For example 650 and 550 are popular.
There are no hard and fast rules for selecting the B coefficient. Basically, the lower you select it, the more favorable it will be to the slower boats. The denominator, B + PHRF, can be the number of seconds it takes to sail a nautical mile in the expected conditions. Another way to look at it is that the denominator divided into 3600 is the average rhumb line boat speed in knots. If you have not been provided with a B factor by the Organizing Authority or wish to set your own, do some testing with previous race results to make sure that the number you select provides reasonable looking results.
Several clubs in Southern California use a Time Correction Factor of 650 / (625 + PHRF), this was tested against previous results and was found to provide the fairest TCF given the SoCal PHRF ratings and the mix of boats that were being handicapped.
US Sailing suggests using the following B factors:
** B Factor **
** When Used**
480
Heavy Air or all off the wind
550
Average conditions
600
** Light air or all windward work **
The numerator, A, is merely a coefficient that makes a nice looking TCF. Select it so that the TCF for the middle of the fleet is about 1.000. The A coefficient has absolutely no effect on the corrected finish order. Changing it will only affect the various margins. Thus if your middle handicap is about 100 and your conditions are average, then the TCF formula would look like the following:
TCF = 650 / (550 + PHRF Rating)
To calculate the corrected time, Sailwave multiplies the elapsed time by the TCF.
TOT scoring usually does not affect the top boats. It usually moves the boats in the middle around a little. If the handicap spread in a class is large, it will tend to tighten things up a bit.
Mark Townsend
s_mark_townsend@hotmail.com
From: jeffblundell@rogers.com
Sent: Saturday, August 14, 2010 3:05 PM
Subject: [sailwave] scoring Time on Time with PHRF
It’s been a couple years since I used Sailwave.
How do I get it to score races as “Time on Time” – I kind of remember I have to go to some “advanced settings” or something like that.
Sailwave can automatically convert your Time-on-Distance PHRF ratings into ToT Time Correction Factors. That is what the A and B numbers do for you. If you aren't sure what A and B numbers to use, here are some guidelines:
1. The denominator (B + PHRF ToD Rating) is intended to be the average number of seconds for each boat to sail around a 1-mile course. Hence, B is intended to be the average time for a boat with a 0 ToD rating. [Formula is: TCF = A / (B+ToDRating)]
2. Normally, you want A and B to be the same - that will mean a boat with a 0 ToD rating will have a ToT TCF of 1.000. Under either system the corrected time will be equal to the elapsed time for a boat with a 0 ToD rating (remember, with ToD you can correct finish times but with ToT you MUST use elapsed times although you can input finish times and a start time to Sailwave and it will automatically calculate the elapsed times before applying the TCF).
3. The A factor has no impact on the order of corrected times for boats. It only impacts the total number of seconds between corrected times for boats, which is why the recommendation is to make your A and B factors the same so the "base" boat is the same.
4. Your A and B factors are set once for every race held. They should NOT be adjusted from race to race or regatta to regatta. They are based on the average wind and course conditions upon which the ToD ratings are based. If your ToD ratings are optimized for 10-14 knots and buoy racing then a number in the range 625 to 650 is a good number. If your ToD ratings reflect point to point racing as well then a lower (i.e., faster) number is probably warranted. With 10-14 knots and random leg courses 550 is often recommended. If your courses are all random leg and your winds are typically much stronger (18+) you might even go as low (i.e., fast) as 450 sec/mi for your A and B factors.
Hope that is helpful.
Art Engel
Marty Bower wrote:
Click on the upper bar "setup", click "scoring system" in the drop
down box, which then opens a box, click the "rating system" tab with in
the box, and you can choose the rating system, TOT PHRF is the 8th one
down. You will also need your A and B numbers to fill in a box just to
the right. Hit "OK" at the bottom and you are finished.
···
Marty
To: sailwave@yahoogroups.com
From: jeffblundell@rogers.com
Date: Sat, 14 Aug 2010 22:05:35 +0000
Subject: [sailwave] scoring Time on Time with PHRFHow do I get it to score races as "Time on Time" -- I kind of remember I have to go to some "advanced settings" or something like that.
I wrote:
> 4. Your A and B factors are set once for every race held.
But, I should have written:
"Your A and B factors are set once for your location."
I think the intend was clear anyway. Sorry for the slip.
Art
Art Engel wrote:
···
Sailwave can automatically convert your Time-on-Distance PHRF ratings into ToT Time Correction Factors. That is what the A and B numbers do for you. If you aren't sure what A and B numbers to use, here are some guidelines:
1. The denominator (B + PHRF ToD Rating) is intended to be the average number of seconds for each boat to sail around a 1-mile course. Hence, B is intended to be the average time for a boat with a 0 ToD rating. [Formula is: TCF = A / (B+ToDRating)]
2. Normally, you want A and B to be the same - that will mean a boat with a 0 ToD rating will have a ToT TCF of 1.000. Under either system the corrected time will be equal to the elapsed time for a boat with a 0 ToD rating (remember, with ToD you can correct finish times but with ToT you MUST use elapsed times although you can input finish times and a start time to Sailwave and it will automatically calculate the elapsed times before applying the TCF).
3. The A factor has no impact on the order of corrected times for boats. It only impacts the total number of seconds between corrected times for boats, which is why the recommendation is to make your A and B factors the same so the "base" boat is the same.
4. Your A and B factors are set once for every race held. They should NOT be adjusted from race to race or regatta to regatta. They are based on the average wind and course conditions upon which the ToD ratings are based. If your ToD ratings are optimized for 10-14 knots and buoy racing then a number in the range 625 to 650 is a good number. If your ToD ratings reflect point to point racing as well then a lower (i.e., faster) number is probably warranted. With 10-14 knots and random leg courses 550 is often recommended. If your courses are all random leg and your winds are typically much stronger (18+) you might even go as low (i.e., fast) as 450 sec/mi for your A and B factors.
Hope that is helpful.
Art Engel
Marty Bower wrote:
Click on the upper bar "setup", click "scoring system" in the drop
down box, which then opens a box, click the "rating system" tab with in
the box, and you can choose the rating system, TOT PHRF is the 8th one
down. You will also need your A and B numbers to fill in a box just to
the right. Hit "OK" at the bottom and you are finished.Marty
To: sailwave@yahoogroups.com
From: jeffblundell@rogers.com
Date: Sat, 14 Aug 2010 22:05:35 +0000
Subject: [sailwave] scoring Time on Time with PHRFHow do I get it to score races as "Time on Time" -- I kind of remember I have to go to some "advanced settings" or something like that.
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