New Posts New Posts RSS Feed: py failing
  FAQ FAQ  Forum Search   Register Register  Login Login

py failing

 Post Reply Post Reply Page  <1 45678>
Author
Merlinboy View Drop Down
Really should get out more
Really should get out more


Joined: 03 Jul 06
Location: United Kingdom
Online Status: Offline
Posts: 3169
Post Options Post Options   Quote Merlinboy Quote  Post ReplyReply Direct Link To This Post Topic: py failing
    Posted: 24 Mar 07 at 8:22am

Originally posted by JimC

Originally posted by Merlinboy

Jim i think you are wrong


I base my opinion on having talked to the people who run the system, on having seen some of the data they use, and on having done a great deal of manipulation of handicap results, what ifs and the like. Oh and a science education that finished up at Imperial College, London. What do you base your opinion on?

well done on your degree in science but i see little relevance to the Py systm, i would of thought that Math's and statistics is more relevant, but anyway jim i was questioning your intellegance or experience, i just stated that i thought you were wrong.  I'm not really interested in entering a "my Dad is bigger then your Dad" style of debate with you.

But i do refer to one of my previous posts, if you look at the total number of Phantoms made (i think approx 1200) and the total number of Merlins made (approaching 3700)  The percentage of late boats with epoxy/ carbon rigs hulls, etc etc. are very very small compaired to the whole class, therefore it ould be wrong for the RYA to change the handicaps for those few cheque book sailors meaning that the people who are still club racing in 20 year old boats are completly out class and hence losing interest.  I have also heard that the RYA ignore the top 5 and bottom 5% of results which also makes sence as to the small changes we see, generally an older phantom/merlin would be a mid fleet sailor sailing somewhere near handicap, hence the small change!

 

Back to Top
Merlinboy View Drop Down
Really should get out more
Really should get out more


Joined: 03 Jul 06
Location: United Kingdom
Online Status: Offline
Posts: 3169
Post Options Post Options   Quote Merlinboy Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 8:25am

Originally posted by Lukepiewalker

It seems a bit unfair to call Jim useless...
But i'm with him. If the data supported it the change would be made. But for most classes where dramatic changes might be expected (usually smaller in numbers), it probably takes longer for the difference to be quantified as there are less of them around.

 

Luke at no point have i called Jim useless ! Please read my post again !  I just expressed that i didnt agree with him this time.  I find jim points of view on technical issues very interesting and dont doubt his intellegance and knowlege BUT on this occasion i think he is wrong hence my post!  So please retract that Slap dash, childish, spiking remark

Back to Top
Scooby_simon View Drop Down
Really should get out more
Really should get out more


Joined: 02 Apr 04
Location: United Kingdom
Online Status: Offline
Posts: 2415
Post Options Post Options   Quote Scooby_simon Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 11:02am

could someone get me the following measurements for a 49er and FF (and maybe merlin, laser, RS800, cherub) etc.  If I have time, I'll plug them into a SCHRS mono version adn see what I get. (I'll need to revise the RM calc as it's not the same for a mono).

  • WS - Minimum sailing weight.
  • CM - Maximum mainsail area.
  • VLM - Maximum VLM. (vertical luff mainsail and for the 49er the luff to the boom)
  • CJ - Maximum Jib Area.
  • VLJ - Maximum VLJ.
  • CSPI - Maximum Spinnaker area.
  • CB - Maximum Board area.
  • VLB - Maximum Board depth below hulls.
  • BEAM - The maximum beam of the boat.
  • NUMTRAP - The number of crew using trapeze.
  •  

    Wanna learn to Ski - PM me..
    Back to Top
    Guests View Drop Down
    Guest Group
    Guest Group
    Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 11:53am
    Originally posted by Merlinboy

    Originally posted by Lukepiewalker

    It seems a bit unfair to call Jim useless...

    Luke at no point have i called Jim useless ! Please read my post again ! 



    In actual fact merlin boy, it's you who should read your own post again.  Dont worry you didnt call him useless, however a correction of your miss spelling of unless would more than likely solve the predicament. 

    Back to Top
    mike ellis View Drop Down
    Really should get out more
    Really should get out more
    Avatar

    Joined: 30 Dec 05
    Location: United Kingdom
    Online Status: Offline
    Posts: 2339
    Post Options Post Options   Quote mike ellis Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 12:14pm
    Originally posted by Scooby_simon

    could someone get me the following measurements for a 49er and FF (and maybe merlin, laser, RS800, cherub) etc.  If I have time, I'll plug them into a SCHRS mono version adn see what I get. (I'll need to revise the RM calc as it's not the same for a mono).

  • WS - Minimum sailing weight.
  • CM - Maximum mainsail area.
  • VLM - Maximum VLM. (vertical luff mainsail and for the 49er the luff to the boom)
  • CJ - Maximum Jib Area.
  • VLJ - Maximum VLJ.
  • CSPI - Maximum Spinnaker area.
  • CB - Maximum Board area.
  • VLB - Maximum Board depth below hulls.
  • BEAM - The maximum beam of the boat.
  • NUMTRAP - The number of crew using trapeze.

     

  • does a laser have any vertical luff? if you could clarify what you mean by vertical luff length i could go and measure my laser right now for you.

    600 732, will call it Sticks and Stones when i get round to it.
    Also International 14, 1318
    Back to Top
    CurlyBen View Drop Down
    Really should get out more
    Really should get out more
    Avatar

    Joined: 17 Aug 05
    Location: Southampton
    Online Status: Offline
    Posts: 539
    Post Options Post Options   Quote CurlyBen Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 12:36pm
    I think the VLM is literally the length of the luff on the Laser (and most other boats). I'm guessing VLJ is Vertical Luff Jib, as opposed to the actual luff length. Presumably CB is area below the hull as well Scooby?
    RS800 GBR848
    Weston SC
    Back to Top
    Stefan Lloyd View Drop Down
    Really should get out more
    Really should get out more


    Joined: 03 Aug 04
    Online Status: Offline
    Posts: 1599
    Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 1:57pm

    Originally posted by Scooby_simon

    The major problem in using measurement for mono dinghy's is that (as I see it)you (somehow) have to factor in the fact boats plane at differet wind speeds and on different points of sail.

    Yes. Predicting keelboat performance from measurement is much easier than predicting dinghy performance because they aren't planing most of the time, plus keelboats are less diverse than dinghies. Huge amounts of money and intellectual effort have been thrown at creating measurement-based rating systems for keelboats, yet none have succeeded in working better than OK-ish for rating boats with very similar characteristics. The idea than a measurement-based system for dinghies would be more successful than PY seems very optimistic to me. 

     

    Back to Top
    Scooby_simon View Drop Down
    Really should get out more
    Really should get out more


    Joined: 02 Apr 04
    Location: United Kingdom
    Online Status: Offline
    Posts: 2415
    Post Options Post Options   Quote Scooby_simon Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 2:07pm

    Originally posted by CurlyBen

    I think the VLM is literally the length of the luff on the Laser (and most other boats). I'm guessing VLJ is Vertical Luff Jib, as opposed to the actual luff length. Presumably CB is area below the hull as well Scooby?

     

    yes to all and for this exercise luff length will do.



    Edited by Scooby_simon
    Wanna learn to Ski - PM me..
    Back to Top
    Stefan Lloyd View Drop Down
    Really should get out more
    Really should get out more


    Joined: 03 Aug 04
    Online Status: Offline
    Posts: 1599
    Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 2:09pm

    Originally posted by Merlinboy

     the total number of Merlins made (approaching 3700)  The percentage of late boats with epoxy/ carbon rigs hulls, etc etc. are very very small compaired to the whole class, therefore it ould be wrong for the RYA to change the handicaps for those few cheque book sailors meaning that the people who are still club racing in 20 year old boats are completly out class and hence losing interest.

    Oh come on, if you are a "Merlinboy" you know that is very misleading. Only around 300 of those boats have been built in the last 20 years and relatively few boats older than, say, 3400 are still racing regularly. Yes there are some but not many. Plenty of 10-20 year old hulls have been updated with carbon rigs.

    Back to Top
    Hector View Drop Down
    Really should get out more
    Really should get out more
    Avatar

    Joined: 10 May 04
    Location: Otley, Yorkshire
    Online Status: Offline
    Posts: 750
    Post Options Post Options   Quote Hector Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 07 at 3:07pm

    We've had this debate before and  I doubt we (or the RYA) will ever come up with a system that pleases everyone.

    That said, it's very important that we have confidence in the PY system to produce fair results and it's clear that confidence is lacking.

    Why? Well it's very noticable that the same boats are mentioned time after time - and from clubs spread throughout the country. Is this just sour grapes or does it indicate that some classes have (on average) better yardsticks than most others? I'd suggest that the system favours certain types of boat and disadvantages others.

    I can't agree with the argument that some classes do well because the best sailors are in that class. It shouldn't make any difference. The PY number is a Yardstick - based on performance. So even if the best 50 helms in the country all happened to be in one class their performance should result in a much lower yardstick for that class. But it doesn't. Why?

    Well, imagine if you ran the PY system at one 'mega' club with lots of different classes, Of course, boats sailed at this mystical club would all sail in the same variety of wind, tide, and wave conditions as each other so the system should work, and eventually the yardstick system should mean that over a long series giving a large variety of conditions,  every class should have an equal chance.  So at that club, let's say that amongst all the others, there are fleets of say 10Fireflys, 10Merlins, 10Lasers and 10Fireballs - each having equally good sailors but a range of boats from brand new to 20 years old - which classes would win and fill the top ten of our fictional long series? I suggest we all know it's the Merlin and Fireball. But why?  I think it's because the top Fireballs and Merlins will benefit from having a higher 'average' yardstick whereas the top Firfly and Laser will suffer because their fleets 'average' will be closer to their own performance as the difference between a new and old boat isn't as significant, I mean that the 'spread' between the front and back of the Lasers and Fireflys is likely to be much less than the 'spread' in the Merlins and Fireballs where the difference in boats is more significant. That's not their fault, it's the system that 'averages' classes and takes no account of the relatively big differences in speed between the front / middle / back of  each fleet.

    In other words, classes that are virtually static in terms of development suffer while classes that have made signiicant changes can (and usually do) benefit.

    So, wouldn't a fairer 'handicap'  include some factor to take into account the likely 'spread' of relative boat.speed within a class?

    I have other concerns - one is transparency - I know a process / formula is available, but why can't the RYA publish other important details. This would include details of the returns - and minutes of their meeting- (as I understand it they 'tinker' with the results). Another is new or radically altered classes - so no change to the I14 when they introduced Tfoil rudders, no official reccomended PY for the RS500, Int moths have a new h'cap for foilers based on what - doubt they do much club racing but Vortex asymmetric still not there despite a good number of returns, etc etc

    Back to Top
     Post Reply Post Reply Page  <1 45678>

    Forum Jump Forum Permissions View Drop Down

    Bulletin Board Software by Web Wiz Forums® version 9.665y
    Copyright ©2001-2010 Web Wiz
    Change your personal settings, or read our privacy policy