Forum: The Racing Rules of Sailing

Portsmouth Yardstick

Satish Kumar Kanwar
A race for Optimists, ILCAs and 420 needs to be conducted. using Portsmouth Yardstick. I solicit the forum members to guide me with any SIs or NoR instructions which will be helpful in the conduct of the races. What yardstick should be followed as there is no historical record of the boats performance is available in this format of racing. Any other issues which merit attention may also be highlighted.
Created: Today 13:19

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Angelo Guarino
Forum Moderator
Nationality: United States
Satish ... may I ask ... why are you not scoring them within their OD fleets instead of attempting to combine them?
Created: Today 13:54
Satish Kumar Kanwar
Angelo,

The format for the racing is designed in a manner where the different classes are intended to sail together.
Created: Today 13:57
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Angelo Guarino
Forum Moderator
Nationality: United States
PS:  if you wanted to crown a sort of "over all" winner .. an option is as follows. 

  1. Score each fleet individually. 
  2. Record the time separation between 1st and 2nd in each fleet. 
  3. Also record the total time for each first place. 
  4. Calc the Time-on-time delta % by subtracting the 2nd place time from the 1st, and dividing that by the total time of each OD first place. 
  5. Sort the TOT delta % high to low and that is your over all 1, 2, 3
Created: Today 14:00
Satish Kumar Kanwar
Thanks Angelo. 

will we be able to further score the other boats in a similar manner so that all boats have a score in the combined result?
Created: Today 14:05
Mark Townsend
Nationality: United States
The RYA website has information about using Portsmouth Yardstick https://www.rya.org.uk/racing/portsmouth-yardstick/ and some NoR and SI recommendations and a list of ratings.

The Portsmouth Yardstick for the five classes you referenced are.
  • 420 - 1110
  • ILCA 4 - 1218
  • ILCA 6 - 1156
  • ILCA 7 - 1103
  • Optimist - 1629  

Created: Today 15:22
Satish Kumar Kanwar
Thanks Mark. That would be very helpful.
Created: Today 15:33
Richard Jones
You can run a handicap race or a pursuit race.

For handicap race  all start together and finish when the race is long enough. All boats start at zero time. Record finish time and the number of laps completed for each boat.
Useful to record each boats time or position for each lap to guage when to finish the race.

You then calculate their individual PY  amended average lap time and multiply it by the number of laps for the leader to get an amended race time .

For a Pursuit race calculate a starting time for each class. Have a countdown display so they start at the correct time.

After the race duration sound a loud hooter and record each boats finish position on the water.

During the race record their positions after each lap.


Created: Today 18:48
Paul Kimmens
Nationality: United Kingdom
Hi Satish

Ideally race them as separate classes but if they did to race together the main issue is that the three classes have significant speed differences so a handicap race where they all start together is going to be difficult because the 420 will be going so much faster than  the optimist so race duration for the boats will be significantly different.  You could resolve this using ‘average  laps’. The faster boats will  do more laps than the slower boats.  You record times for all boats and for the boats  that do fewer laps you calculate what there time would be if they sailed the same number of laps as other boats. You then calculate the corrected times using the PYs to determine the result.

Alternatively, and possibly a better option, is to run a pursuit race. The duration of the race is set to a fixed  length and the slowest boats start 1st and this is the nominal start time. Faster boats start at set time delays after the nominal start based in their PY. The race runs for the set duration From the nominal start time. A sound signal  is made to indicate the end of the race. The winner is the boat in the lead, 2nd following boat etc etc.  Takes a big of maths to work out the starting delay but not difficult. Benefit is that the start line is less crowded as boats are starting at different times. Limitations are that you can’t have general recalls, only individual and when the finishing hooter sounds some boats may be on different sides of a beat to windward so may be difficult to determine positions.

At my club we use both methods when there is a mix of varying classes and both methods work well. 
Created: Today 19:53
Calum Polwart
Kimmens has highlighted the main issue - you need to use average laptime.

That means your course needs to start and finish in the same place and use laps. People sometimes do hideous things like move the committee boat to finish like they might on a standard race. Don't. You can't. Because you need lap numbers.

Pursuits are great. You can see how it's panning out. BUT...

1. The poor guy in the Oppi is sailing 60% longer than the 420, but in terms of strength is likely the less physical sailor.

2. The finish is handled in a variety of ways. In the perfect world you'd have a helicopter overhead and freeze frame the boats to capture places

3. The start times - sometimes people round them to whole minutes. e.g. the Oppi starts at time 0 and the laser at time 12 minutes later.   The snag is if your ICLA6 and 7 start at say 11 minutes and 13 minutes because 11:25 rounded down and 12:35 rounded up. But in a normal race you'd not accept being told you can start 25 seconds early or must start 25 seconds late. And front runners don't finish with 50 seconds gaps...  So I would do exact second starts... Which makes the start hard work (very doable with the DSRC app)


There are other handicap tables like Great Lakes which could be better if on a big lake rather than sea
Created: Today 20:15
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Angelo Guarino
Forum Moderator
Nationality: United States
Paul ... I agree. Let each fleet race in OD and calc a relative performance within each fleet. 

I hadn't really thought this design out until this thread ... but each boat's performance  can be "normalized" by either the total time of the 1st place boat (or avg-time or last-boat-time).  Formula is ... 

RelativeFinish = (BoatTime - FirstBoatTime)/FirstBoatTime

Then put all the boats in one list and sort. 

One could normalize against the avarage time for each fleet too .. if one thought that fairer. 

So each boat is then scored a relative performance within the fleet and then combined. 

If normalized by the FirstBoatTime, each OD winner would have a score of zero.  That tie is broken by the largest relative gap to 2nd place. 

So the winners of each OD fleet gets 1/2/3 .. then rest are sorted in order. 
Created: Today 21:11
Calum Polwart
Oh and you asked for NoR and SI.

I'd say this is NoR territory - I might not want to Handicap race.

If it's purely handicap - Section 15 should imply have a sentence like "Places will be calcul ted using the RYA Portsmouth Yardstick Scheme, using average lap times."

If you are planning first Oppi, first ILCA 6 etc, you need to be more careful.  A lot of people will simply take the highest ranked Oppi in the overall results table. But you could also filter only the Oppies and take their times as places and use that. It can give different results.  It depends what you want the race to achieve
Created: Today 20:47
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John Allan
Nationality: Australia
PY is designed to do exactly what Satish wants to do: enable dinghies of different classes to race against one another in the same race.  It has done this successfully for over 70 years.

It is a time on time system.  it is unnecessary to use complex average lap calculations.  Merely apply the PY to each boats elapsed time for the course.

Yes, the NOR should state that the PY handicap is being used and should state precisely which 9of the numerous available) PY lists will be used, or if there are only a known limited number of classes racing, could list the PY that will be used for each.
Created: Today 22:56
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