Hi
Newbie here
My club uses sailwave to calculate the results for Average Lap
Racing. Recently we have had situations where a slower boat in a
particular class has completed fewer laps than the fastest boat in
the same class. With a significant drop in wind for the last lap,
when calculated, the average lap time of the slower boat, over fewer
laps, resulted in the slower boat winning the faster boat.
The guidelines for average lap racing make provisions for this by
applying a Multiplier thereby increasing the times of the boats
sailing fewer laps. The Multiplier is only applied to boats with the
same PN.
There is a PDF file in the Technical Section of the RYA site.
http://www.rya.org.uk/NR/rdonlyres/CCC3B823-0FA6-466D-AA98-
805479B9C07C/0/20075AverageLapRacing.pdf
Is it possible to use sailwave to apply the Multiplier or can it only
be done manually.
Thanks
Glynn
This is a very frequent situation when races on a fixed time are sailed with a finish time some time after the evening wind is expected to drop. I had sometimes identical boats, at some minutes from each other during the whole race, and ranked in reverse order, because the first one had to sail another full lap in a vanishing wind.
There is a solution… but Sailwave is not the problem, only the method of calculation as described in the SI, to be implemented in Sailwave if there are interested users.
Principles :
- The boats are sailing a number of FULL laps N in an elapsed time Tn, smaller then the reference time.
- They are trying to sail a further lap before a defined time limit, usually two times the expected time for a normal lap, and a second finish time Tn+1 is recorded (I use to declare the finish line open 20 minutes after the start and record all finishing times till the latest for each boat after the reference time).
- The boat is ranked on elapsed time on a number of laps Ne = N + (RefTime - Tn) / (Tn+1 - Tn)
- Optionally, if the length of a lap L is known, the distance on the target time De = Ne * L
- On handicap, depending on the system used (TMF or Yardstick), Nc = Ne * TMF or Nc = Ne * Ybase / Y, and Dc = De * TMF or Dc = De * Ybase / Y
The philosophy is that a boat is given her number of full laps before reference time, plus a part of the last lap, at here average time of this lap, until the reference time has expired.
A wrong method could be to finish the race at any buoy. Some legs are slow, others are fast and all boats should have the same amount of slow and fast legs.
There could be still unlogical results, as two similar boats could pass N laps together, thar the first one leads until the reference time has expired, further the other one takes the lead and finishes ahead, he wins, even if he did not on the water at reference time. However, they could be at reference time on both sides of the racing area, halfway between marks, difficult to give them a right place at that level…
What if… before going round the buoys there is a first single leg upwind? Probably a bad idea, but if the length D0 of this first leg is known, and this distance should be as short as possible, compared to the length of a lap (1 NM for a 10 NM lap to be sailed 12 to 15 times in 24 hours), the effect is limited. This initial distance could simply be added to the distance sailed De before applying handicaps.
Phil DE TROY
Webmaster Federation Francophone Belge du Yachting
···
----- Original Message -----
From:
glynn_fox
To: sailwave@yahoogroups.com
Sent: Friday, March 09, 2007 2:24 PM
Subject: [sailwave] Average Lap Racing - Multiplier
Hi
Newbie here
My club uses sailwave to calculate the results for Average Lap
Racing. Recently we have had situations where a slower boat in a
particular class has completed fewer laps than the fastest boat in
the same class. With a significant drop in wind for the last lap,
when calculated, the average lap time of the slower boat, over fewer
laps, resulted in the slower boat winning the faster boat.
The guidelines for average lap racing make provisions for this by
applying a Multiplier thereby increasing the times of the boats
sailing fewer laps. The Multiplier is only applied to boats with the
same PN.
There is a PDF file in the Technical Section of the RYA site.
http://www.rya.org.uk/NR/rdonlyres/CCC3B823-0FA6-466D-AA98-
805479B9C07C/0/20075AverageLapRacing.pdf
Is it possible to use sailwave to apply the Multiplier or can it only
be done manually.
Thanks
Glynn
Hi Glyn, it's something that I will do at some point. But for now it's
manual hack if necessary.
CJ
···
-----Original Message-----
From: sailwave@yahoogroups.com [mailto:sailwave@yahoogroups.com]On
Behalf Of glynn_fox
Sent: 09 March 2007 13:25
To: sailwave@yahoogroups.com
Subject: [sailwave] Average Lap Racing - Multiplier
Hi
Newbie here
My club uses sailwave to calculate the results for Average Lap
Racing. Recently we have had situations where a slower boat in a
particular class has completed fewer laps than the fastest boat in
the same class. With a significant drop in wind for the last lap,
when calculated, the average lap time of the slower boat, over fewer
laps, resulted in the slower boat winning the faster boat.
The guidelines for average lap racing make provisions for this by
applying a Multiplier thereby increasing the times of the boats
sailing fewer laps. The Multiplier is only applied to boats with the
same PN.
There is a PDF file in the Technical Section of the RYA site.
http://www.rya.org.uk/NR/rdonlyres/CCC3B823-0FA6-466D-AA98-
805479B9C07C/0/20075AverageLapRacing.pdf
Is it possible to use sailwave to apply the Multiplier or can it only
be done manually.
Thanks
Glynn
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