The RYA Portsmouth Yardstick guide to running races provides a calculation for generating and applying a modifier to boats in a class that sail fewer laps than other boats in the same class in order to adjust results where originally faster boats are judged to have been disadvantaged on their last lap due to changes in wind and/ or tide.
“If a boat ends with a corrected time greater than a boat which completed less laps but has the same PN, a modifying calculation should be applied as follows:
Modified time = Corrected time x multiplier
Multiplier = (slowest x (fastest laps – 1)) / (about to finish time x fastest laps)
Where:
Fastest Laps is Actual Laps completed by the fastest boat in the group. Slowest is the Elapsed Time of
the slowest boat in the group[*, to complete Fastest Laps[1]]. NB. This is only applied to a group of boats with the same PN where one or more have been effected by sailing differing number of laps and the corrected times do not reflect a fair outcome.”
The modifier is then used to adjust the corrected time calculated for the boats that completed fewer laps.
Based on my review of other forum posts it seems that SailWave is not able to calculate and apply the modifier. Is this correct?
If SailWave can apply this modifier could you please point me to the method for entering the required ‘about to finish time value’.
If SailWave does not apply the modifier are there any plans to implement this feature?
Thank you.
(I appreciate this topic has come up before but, I just need to check nothing has changed.)
Thank you for the incredibly swift response that confirms the answer to my main question .
In relation to the possibility of future development:
I certainly see the challenge with recording the individual lap times. But, I believe this is recognised by the formula provided by the RYA which makes it unnecessary.
The formula calculates an adjustment based on the difference in elapsed time between the fastest boat to complete the additional lap and the slowest boat that completed the additonal lap.
That is then used to adjust the elasped time of boats that completed one less lap.
The time of the about to finish signal is used as a proxy for the time the fastest boat crossed the line at the start of it’s last lap becuase it is recognised that that actual time is likely not recorded, or easy to record.
All that is missing from the current data collected by SailWave is the time for the about to finish signal.
SailWave has Fastest Laps recorded as the most laps sailed in the race by a boat with that PN.
SailWave has Slowest recorded as the elapsed time for the slowest boat with that PN that sailed laps equal to Fastest Laps.
Multiplier = (slowest x (fastest laps – 1)) / (about to finish time x fastest laps)
Would this understanding make this more practical as a future development?
Hi Ben, We have a very simple manual adjustment at our club, If a boat of the same class sails more laps then it will not be scored after a boat that sailed an extra lap. (as at the time the slower boat was finished it was behind the other boat) This only occasionally happens and we just manual adjust finish time or points so slower boat finishes directly behind the other boat. I would not go down the route of calculating adjusted time for one PY (class) in relation to changing conditions as that scenario applies to all boats in all class where average lap times are used. Keith
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