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#61 native

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Posted 31 October 2018 - 12:20 PM

Nice
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#62 markm

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Posted 31 October 2018 - 12:35 PM

Mr Around the house, Designer as it happens is likely the least conflicted person on the committee, all of us race so we all have conflicts.

Where practical anyone with a conflict isn't included in a decision.  Where not, They still of course won't be making a decision but may be asked for factual information or be asked to give an opinion with us knowing a conflict exists.

I'm likely the most significant issue as I'm providing a lot of the information on which decisions are based.  If Fun-n-Games comes up for PHRF, I'll pass a report to whoever is handling the revalidation and that's pretty much it for my involvement.

YNZ are in the process of putting in a new system and one outcome will be to eliminate even that much involvement.

Establishing a base PHRF is very dependent on information available. 

The easiest of course is class boats, if we have the design already, well decisions become very easy.

Quite a few now are imports, either production boats or second hand import.  One of our approaches for these is hunting out existing ratings, adjusting what we find to align with NZ PHRF and also adjusting based on our view of how the rating system handles a particular design or design characteristic versus how we do.  For example, IRC can be pretty brutal to smaller high performance boats so we try to factor that in.

Similar but different approach, if the owner has polar information, that we can certainly use.  Helps to know the source of the polars as not all polars are equal but definitely of potential interest to us if available.

We will often do some comparison work with boats in the existing PHRF database.  Quite a few of our designs we're pretty confident of our base PHRF numbers.  With a comparative approach you try to identify a design that's reasonably similar and where your confidence in the base PHRF is high and assess the differences.

As mentioned earlier in this thread, there are a couple of performance calculators around which we can put measurements into to get a guide.  They have limitations but if you keep within them or work around them, again you can get a pretty reasonable idea.

If we're really struggling with our approach at this stage, may do the comparison approach but using another rating system (ORC is pretty good for this) finding a similar design and adjusting for the differences.

There's also looking at existing results.  For this, it helps a lot to be familiar with the crew because they are such a big influence on the result, far more than most realise.

Usually from that something has worked for us, often a couple have and we'll compare the differing outcomes.


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#63 Knot Me... maybe

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Posted 31 October 2018 - 03:40 PM

Thanks Mark.

Good to have someone explaining it in a bit more detail, it helps understand what it's about far better.


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#64 Fish

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Posted 01 November 2018 - 10:16 AM

I think its time to drop Phrf and run racetrack as that's a true PHRF Mark gathers all the information from published or distributed Results and its pretty accurate PHRF as run by YNZ is a joke . 

Just a note on using racetrack. Prior to the Coastal, SNS had done 6 races. The average racetrack rating of those 6 races was 0.786 - that is higher than the PHRF rating applied for the Coastal of 0.768 (Passage).

 

SNS's racetrack rating is now 0.736 (after 9 races), clearly heavily affected by a 0.606 for the Coastal. So for a new boat with no racing history, the racetrack rating can jump around like a crazy woman - it isn't reliable for using to handicap events with.

 

I was a little surprised SNS was put into Div 3 for the Coastal, and on seeing the complaint about PHRF here sussed the rating. Based on the rig being ex Ross 930, compared the rating to those of Ross 930's. There is some variance on the base ratings, I'm assuming for those with turbo'd keels, bowsprits and extra fruity sails (FRO's and the like).

 

SNS has a slightly longer LWL, and a slightly lighter displacement than a Ross 930, but is very similar in a lot of other aspects, especially rig and sail dimensions. SNS's base handicap is within the range of the Ross 930's, and is basically the same as those with a new keel (i.e. similar keel to SNS). I can't see a major disparity on the base rating when compared to similar boats.

 

What I did notice is SNS's LP is fairly short at 3.6 m (compared to a J of 3.3 m). Given the Coastal was an upwind affair with a light breeze dieing off, having a small headsail and no Zero is going to be really punishing. I'd think if the Coastal was a classic downwind 20 knts, the result and this thread would be entirely different.

 

I've always thought it takes a while to tune in a new boat and really get it to boogie (possibly even a whole season, depending on how sharp the crew is). Not even pro boats would expect a blinder in their first major event for a new boat. Likewise, it takes time / races to get a consistent picture of a boats rating, as shown by the racetrack number being higher than the PHRF ahead of the Coastal. I can't see a major issue with PHRF here, and given suitable conditions SNS will be able to smoke that, and others may be criticising PHRF for being too soft here.

 

The handicappers jobs is thank-less, so I just wanted to put in my 2 cents and thank the handicappers, both at YNZ and all the local club handicappers around the country, for running the numbers and putting up with the criticism when someone isn't happy with their number. I get the vague impression handicappers aren't inundated with people saying the handicapper is great, their rating is way too low.....


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#65 Knot Me... maybe

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Posted 01 November 2018 - 10:31 AM

 I get the vague impression handicappers aren't inundated with people saying the handicapper is great, their rating is way too low.....

 

3 weeks ago I had a prominent Akl yachtie come to me and loudly proclaimed in the grumpy tone he can do so well 'My handicap is too low, I am very insulted'.

 

I looked around for cameras, Alan Funt, TV1/3 logos and things like that. Nothing seen. Weird I thought, what's the angle being played here???

 

There was none, he was genuinely pissed off his handicap was lower than he expected. So I said no worries I'll make sure next time you get hammered. I told those who needed to know and I quote "X is bitching about his H/C being too low, slaughter him next race", they did and and said yachtie is now a happy camper.

 

Not quite a X File but still in the 'weird sh*t that happens' category.


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#66 Fish

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Posted 01 November 2018 - 10:35 AM

Exactly KM, especially in club fleets, people can get offended when their rating puts them in the 'slow division'.

 

Its a minefield out there for volunteers who run the data for racing...


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#67 native

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Posted 01 November 2018 - 10:41 AM

Most of the fun is had fighting for line with similar performing boats, ultimately its up to the club to arrange divisions that are reasonably close in the same conditions.


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#68 Knot Me... maybe

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Posted 01 November 2018 - 11:14 AM


The handicappers jobs is thank-less,

 

I've been pushing my people to not fiddle in our Top Yacht system. 2 seasons ago I sat and fiddled all the H/c's into a tidy place. Since then we have let TY run the handicaps and it is getting it sh*t together very well with corrected times now often only seconds apart.

 

I have made the odd very small tweak to the odd boat for the odd unusual thing but otherwise just let it run, within the parameters we set it up with. I have also 'created' a couple of boats in the system to allow for the assorted crews each boat often has. As mentioned earlier we do have 'Boat Name', same 'Boat Name CC' and a few same 'Boat Name LR'. That allows the system to work for all the configurations those boats sail in. Most configuration differences are crew related as in same boat but totally different crews doing quite different races. When we only had the one listing per boat some configurations ended up with a ridiculously good H/C but others were pushed out in looony tunes land.

 

But now the system has been left pretty much to it's own devices for 2 seasons it is doing a great job of handicapping and getting tighter each day. One of the best bits with using that is when someone bitches you can say 'Don't bitch at me, speak to the handicapper' and then point at the laptop :)


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#69 Fish

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Posted 01 November 2018 - 11:20 AM

Just to clarify KM, does Top Yacht run automatic handicapping?

Is it a purely performance based adjustment?

Can the club set or influence policy around it, like percentage change, weighting for key events etc?

 

I can see a boat used for ladies racing, rum racing, short handed racing, fully crewed series racing and big event races would need more than one handicap in the system, especially if completely different crews and skippers are involved.


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#70 Knot Me... maybe

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Posted 01 November 2018 - 11:32 AM

Yeap, all performance based.

 

We set the parameters we want, mostly limits on how much a boat can change at once, upwards or downwards, and a few things like how many races make a series and after how many do drops kick in and how many. Lots of things like that.

 

As boats finish we tap the keyboard and bingo the finish time is locked in. When all boats are done push the process button and a second or 2 later you are presented with the results all done. I usually can see all the finished results before the last boat has managed to undo it's halyard to drop it's main.

 

On the H/C results it has a green line thru one boat. That boat is the one that sailed closest to it's handicap, so if you are above that line you beat the handicapper, below that line you need to pull finger as the handicapper reckons your faster.

 

On that it lists boat name, H/C used in the race, finish time, elapsed time plus some bonus bits. Those being the handicap the boat sailed needed to have in that race for it to equal the datum boat. It also shows us what the handicap will change to next race, 1 and 2 move up, second to and DFL down a bit. There is some good info there and it often gives me plenty to give some boats sh*t with at the prize giving :)

 

 


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