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Portsmouth or SCHRS ???
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#288633 - 02/14/18 04:30 PM Re: Portsmouth or SCHRS ??? [Re: samc99us]  
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Originally Posted by samc99us

I was trying to be idealistic, because our local fleet did as you are suggesting for 2 years and it doesn't result in a 'fair' rating per SCHRS (see the jib vs. spinnaker area issue above). If your fleet is okay with this, then go for it. I just kindly suggest setting up a fleet SCHRS focal point that can generate ratings for the frankenboats given basic input data for future events. That is what we do locally-I run the ratings as I volunteered, it is fast for me, and my number doesn't change (F18's have been 1.000 for a while now). I will kindly generate numbers for other boats if they can provide the input data, or if I am at an event and not fixing the bottom of my daggerboards, I will help measure. I will see what I can do to become an approved measurer.



Sam,

Once you do become an "approved measurer" let me know what needs to be done as this is something I may want to do...

With that, the calculator and the other instructions that are online will work as much of the data has already been done... that is some one with a Prindle or Dart 18 shows up with a new square top all I need to do is go to the rating table, plug in the known data, then the new data for the sails (CM & CJ) and get a number.... easy peasy lemon squezzy right?????? Wrong!!!!!!!

The problem I had last year was that some sailors were not able to get the required measurements from the sail makers.. Even with my new sails for the P18 from Whilewind, Chip almost choked when I sent him the chart below noting that he didn't have the time to do this.. In the case of the Dart 18 sailor he noted the Glasser was not able to do this asw well... which was suspect to me, but that is another story..

[Linked Image]

I am going to try and messure my new sails and will send you the messurements to see if they "jive" with mine..

More to come

-- Have You Seen This? --
#288634 - 02/15/18 06:29 AM Re: Portsmouth or SCHRS ??? [Re: Ventucky Red]  
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bacho Offline
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Originally Posted by Ventucky Red
Originally Posted by samc99us

I was trying to be idealistic, because our local fleet did as you are suggesting for 2 years and it doesn't result in a 'fair' rating per SCHRS (see the jib vs. spinnaker area issue above). If your fleet is okay with this, then go for it. I just kindly suggest setting up a fleet SCHRS focal point that can generate ratings for the frankenboats given basic input data for future events. That is what we do locally-I run the ratings as I volunteered, it is fast for me, and my number doesn't change (F18's have been 1.000 for a while now). I will kindly generate numbers for other boats if they can provide the input data, or if I am at an event and not fixing the bottom of my daggerboards, I will help measure. I will see what I can do to become an approved measurer.



Sam,

Once you do become an "approved measurer" let me know what needs to be done as this is something I may want to do...

With that, the calculator and the other instructions that are online will work as much of the data has already been done... that is some one with a Prindle or Dart 18 shows up with a new square top all I need to do is go to the rating table, plug in the known data, then the new data for the sails (CM & CJ) and get a number.... easy peasy lemon squezzy right?????? Wrong!!!!!!!

The problem I had last year was that some sailors were not able to get the required measurements from the sail makers.. Even with my new sails for the P18 from Whilewind, Chip almost choked when I sent him the chart below noting that he didn't have the time to do this.. In the case of the Dart 18 sailor he noted the Glasser was not able to do this asw well... which was suspect to me, but that is another story..

[Linked Image]

I am going to try and messure my new sails and will send you the messurements to see if they "jive" with mine..

More to come





The computer does not spit out those numbers. Gotta be measured by hand. I am sure they can measure them for the customer. Its just another $75 charge.

#288635 - 02/15/18 07:35 AM Re: Portsmouth or SCHRS ??? [Re: Mark Schneider]  
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That depends on the software Bacho. I don't really see how you can design class legal sails in a software package that doesn't give you sail area. I would bet good money that North, Quantum's and Doyle's in-house software gives you sail area, as does Smart Azure but I could be wrong. All my wing design tools generate area...now, the final product? That could still be different than what you drew for a myriad of reasons that you know waay more about than me.

Why Glaser can't provide this, I don't fully understand. They can measure F18 sails so they definitely can measure other class sails...but they should be providing the area. Its frustrating to me because we are working on a Nacra Inter 20 rules re-write locally that doesn't change the sail area but opens up the builder options, yet Glaser won't tell us the area of the sails they have built for the class (that we would like to make sure fit within the rules).

Ventucky Red, this is a helpful link: http://usf18.com/measurement-tips-and-pics/

I would also download the F18 measurement template. It has all the math built in for the diagram you have.


F18 Infusion
#288636 - 02/15/18 08:40 AM Re: Portsmouth or SCHRS ??? [Re: samc99us]  
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Originally Posted by samc99us



I would also download the F18 measurement template. It has all the math built in for the diagram you have.


Mr. Google is not helping me here.... do you have a link or can you send me the spreadsheet?

#288637 - 02/15/18 12:08 PM Re: Portsmouth or SCHRS ??? [Re: Mark Schneider]  
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F18 Infusion
#288639 - 02/15/18 04:00 PM Re: Portsmouth or SCHRS ??? [Re: samc99us]  
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bacho Offline
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Originally Posted by samc99us
That depends on the software Bacho. I don't really see how you can design class legal sails in a software package that doesn't give you sail area. I would bet good money that North, Quantum's and Doyle's in-house software gives you sail area, as does Smart Azure but I could be wrong. All my wing design tools generate area...now, the final product? That could still be different than what you drew for a myriad of reasons that you know waay more about than me.

Why Glaser can't provide this, I don't fully understand. They can measure F18 sails so they definitely can measure other class sails...but they should be providing the area. Its frustrating to me because we are working on a Nacra Inter 20 rules re-write locally that doesn't change the sail area but opens up the builder options, yet Glaser won't tell us the area of the sails they have built for the class (that we would like to make sure fit within the rules).



The software certainly spits out a SA number, buts its not the same number that you will arrive at measuring by hand as shown above. They can be different for a number of reasons, some of which I do not fully understand yet myself. If they gave you a number from their computer, its not a number likely to be recreated when someone attempts to measure that sail by hand.

Anyways, if you want Glaser or anyone else to fill out that chart, they will need 2 people and half an hour with the sail in their possession to get these numbers. Thats why they charge $75 extra for a "certified" F18 sail. IMO, the certification only says that on X date the sail measured X when measured by approved methods.

Last edited by bacho; 02/15/18 06:00 PM.
#288640 - 02/15/18 07:02 PM Re: Portsmouth or SCHRS ??? [Re: samc99us]  
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Jake Offline
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Originally Posted by samc99us
That depends on the software Bacho. I don't really see how you can design class legal sails in a software package that doesn't give you sail area. I would bet good money that North, Quantum's and Doyle's in-house software gives you sail area, as does Smart Azure but I could be wrong. All my wing design tools generate area...now, the final product? That could still be different than what you drew for a myriad of reasons that you know waay more about than me.

Why Glaser can't provide this, I don't fully understand. They can measure F18 sails so they definitely can measure other class sails...but they should be providing the area. Its frustrating to me because we are working on a Nacra Inter 20 rules re-write locally that doesn't change the sail area but opens up the builder options, yet Glaser won't tell us the area of the sails they have built for the class (that we would like to make sure fit within the rules).

Ventucky Red, this is a helpful link: http://usf18.com/measurement-tips-and-pics/

I would also download the F18 measurement template. It has all the math built in for the diagram you have.



There are several different prescribed sail area measurement systems and some classes had their own that varied. Sails can be designed to work within a particular system to have a little more real world sail area and still measure in. The measurements are all just an approximation of area taken at a few reasonably practical points. The sail area generated from the software used to design a sail will be different from a sail that's measured manually...and to measure in to any rule, the sail needs to be measured per the prescribed method. I seem to remember that F18 originally had a slightly simpler, self prescribed, sail measurement procedure and that they adopted the ISAF method when they become a fully fledged ISAF class. Both systems would come up with a different number for any given sail and neither would match the software number. A sail measurer is usually listed/recognized with the class they're measuring for and some classes require some level of sailing organization certification to be a measurer. You may also be recognized by one class and not another. In order for Glaser to measure a class sail, he has to learn the measurement method (assuming SCHRS is different) and actually perform the measurement...if it's not a system that he (or Pease) will use often enough, I can see why he would have chosen to not offer the service.

That said, the Nacra 20 sails? I can probably guess why nobody would want to get involved with those numbers! Political football that probably has a pattern of variation in a distinct path...but I can only guess.

(BTW, Bacho has been designing sails in various software packages from low budget to high end and I've helped produce a few - I was also an F18 sail measurer for a while).

Last edited by Jake; 02/15/18 07:27 PM.

Jake Kohl
#288642 - 02/16/18 12:54 PM Re: Portsmouth or SCHRS ??? [Re: bacho]  
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Originally Posted by bacho


The software certainly spits out a SA number, buts its not the same number that you will arrive at measuring by hand as shown above. They can be different for a number of reasons, some of which I do not fully understand yet myself. If they gave you a number from their computer, its not a number likely to be recreated when someone attempts to measure that sail by hand.



When my in laws redid their kitchen, the counter guys did the measurements by laser.. I wasn't there, but my FIL (who was an Apollo project rocket surgeon for both Rockwell and Grumman) told me it was pretty slick... they had some pretty odd angles along with an island that had an arched side (leech) and the finished product fit like a glove right down to the mm when they installed it...

I am wondering if this technology could work for us?








Last edited by Ventucky Red; 02/16/18 12:54 PM.
#288643 - 02/17/18 07:46 AM Re: Portsmouth or SCHRS ??? [Re: Mark Schneider]  
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This is a very interesting thread, and brings out a lot of really great points.

As Jake said, there are different levels of regattas, and managing handicaps should be taken as seriously (or not) as the level of regatta. But, you run the risk of alienating anyone who does take it seriously when you start to bend rules. Finding the right balance, and setting the expectation/tone (communication!!!) is the key.

If we move to a new system, or even just start seeing more handicap racing, it will put more emphasis on getting the ratings right before racing. Unless you have a dedicated volunteer (or team), don't expect much to happen on Saturday morning of a weekend regatta, in terms of settling numbers.

But, we've all been to regattas where someone has clearly been allowed to break a class rule, just to get the regatta numbers up. Whether racing OD or handicap, this is not a problem if handled well (communicate well with the legal boat owners, and don't start letting the whole thing turn into frankenboats over time), and as long as the illegal boats don't win.

Mike

#288652 - 02/20/18 11:44 AM Re: Portsmouth or SCHRS ??? [Re: bacho]  
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Originally Posted by bacho
Originally Posted by samc99us
That depends on the software Bacho. I don't really see how you can design class legal sails in a software package that doesn't give you sail area. I would bet good money that North, Quantum's and Doyle's in-house software gives you sail area, as does Smart Azure but I could be wrong. All my wing design tools generate area...now, the final product? That could still be different than what you drew for a myriad of reasons that you know waay more about than me.

Why Glaser can't provide this, I don't fully understand. They can measure F18 sails so they definitely can measure other class sails...but they should be providing the area. Its frustrating to me because we are working on a Nacra Inter 20 rules re-write locally that doesn't change the sail area but opens up the builder options, yet Glaser won't tell us the area of the sails they have built for the class (that we would like to make sure fit within the rules).



The software certainly spits out a SA number, buts its not the same number that you will arrive at measuring by hand as shown above. They can be different for a number of reasons, some of which I do not fully understand yet myself. If they gave you a number from their computer, its not a number likely to be recreated when someone attempts to measure that sail by hand.

Anyways, if you want Glaser or anyone else to fill out that chart, they will need 2 people and half an hour with the sail in their possession to get these numbers. Thats why they charge $75 extra for a "certified" F18 sail. IMO, the certification only says that on X date the sail measured X when measured by approved methods.


That makes a lot more sense Bacho. Not an easy nut to crack given those limitations.


F18 Infusion
#288654 - 02/21/18 06:24 AM Re: Portsmouth or SCHRS ??? [Re: Mark Schneider]  
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Jake Offline
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The reason that sail measurement methods and computer design softwares differ in sail measurement reading is because the software is using advanced math (derivation, etc) and getting a very accurate sail area figure. It is also taking into account the entire surface area that is formed by the 3D shape that you don't get when you lay a sail flat on the ground. Physical sail measurement methods generally use a series of defined triangles to approximate the sail area as well. Also, because sails aren't straight line triangles, but the prescribed measurements are, the result of a physical measurement is only an approximation of sail area - but not the actual sail area. The accuracy of a sail measurement system is correlated to the number of measurement points and since it's impractical to have (for instance) 3,000 measurement points, most systems make a compromise in the number of measured points vs. the accuracy of the result. However, if there isn't enough accuracy with the measurement system, the door opens to sail designs that work around the system and stuff sail area into the sail in ways that the measurement system cannot measure. It's all a balance in practicality, accuracy, and keeping things in check.



Jake Kohl
#288655 - 02/21/18 10:03 AM Re: Portsmouth or SCHRS ??? [Re: Mark Schneider]  
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samc99us Offline
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Jake,

I got all that. The biggest issue is with classes that don't have or use a prescribed sail area measurement system. I recommended the F18 one because it has a reasonable degree of accuracy, there are step by step instructions and a form that does all the math for you once you've done the measuring. Is it the best system? Probably not. Will it get the job done for SCHRS? Most likely.


F18 Infusion
#288656 - Yesterday at 10:30 AM Re: Portsmouth or SCHRS ??? [Re: samc99us]  
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Jake Offline
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I thought F18 had adopted the standard ISAF measurement method when they became a recognized class. I'm pretty sure the A-cat uses that system...would probably need to research a bit. Either way, I agree that the F18 system is pretty thorough with a well thought out form.


Jake Kohl
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