Hi Jon,
I’ve just started using the NHC system to record our Cruiser races, but I fear I must be doing something wrong.
For our recent race, we had six boats racing. Each has a base number and, afterwards, an elapsed time.
I put my data into Sailwave and, as a check, into Hal and the RYA spreadsheet. I get the same corrected times in all, as expected, but the resulting new TCF is different for all three methods. I want to use Sailwave for our results but, due to the three different TCFn/ra, I’m not confident I’m using Sailwave correctly.
Bearing in mind that I’m just trying to make sense of my results, the following three points might be where I’m going wrong.
1) The RYA document sub-titled ‘Results Software Calculations 2014’, paragraphs under ‘NHC - Scoring Programme Specification 2015’ is not totally clear to me. It appears that the ‘current set evaluation is 1 standard deviation for both positive and negative performance ...’, but when I use the Sailwave external view to show the number of standard deviations used, I see 1.5 for over performance and 1.0 for under performance.
2) Similarly, ‘... the current levels for standard adjustment are set at 0.3 and 0.7 and are the same for over and under performance ...’, while Sailwave shows 30% and 15%.
3) Also, for extreme performance the ‘... calculation reduces the amount of adjustment a boat receives by the amount of over/under performance that has been highlighted as extreme based on the standard deviation analysis’. This last sentence results in a variable adjustment for each extreme performer, while Sailwave shows extreme performance adjusted to 15% and 7.5%.
My version of Sailwave (2.28.1) seems to be using the RYA specification for 2014, without the 2015 specification. Am I reading the Sailwave external spreadsheet correctly? Is there another version of Sailwave NHC template that includes the 2015 specification? Or, did the RYA decide the 2015 specification was too complicated to implement and revert to the 2014 specification?
Grateful for your help.
Hi,
Sorry - I’m away at present scoring a series.
Sailwave is capable of scoring to either NHC2014 or NHC2015 using the external mode depending upon which template is used.
Both are supplied with the Sailwave install the default is NHC2014.
NHC2014 is also built into Sailwave for internal calculation without the use of Excel.
The problem with the NHC2015 is that the documentation for the method of calculation and the worked example don’t agree so until that was clarified I’ve never adopted it as the standard.
You can, however, use the NHC2015 template with the external/custom mode and this will calculate to the NHC2015 specification.
The big advantage of using Sailwave with the external mode is that you have a full audit path showing you the calculations and if you wish can create your own variations.
If you don’t have the NHC2015 template you can download it from https://www.dropbox.com/s/9d254seklf2cexe/SWNHC2015.xls?dl=1
If you have any questions please let me know.
Regards
Jon
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Jon Eskdale
07530 112233
Skype “eskdale”
Excellent Jon. Thank you so much. I’ll download the NHC2015 template and play around with that one. I agree with you that the documentation and worked example don’t agree. They are both hopelessly obscure, and not at all user friendly.
Thank you again for all your work on Sailwave, it is really appreciated.
Chris.
Hi Jon,
Just using the default settings on SailWave, i.e. just clicking in RYA NHC and internal mode, I get NewRating values from 1.037 to 0.803 for the six boats that raced.
If I change the ‘RYA NHC Mode’ settings to ‘External/Debug’ I get the Excel Spreadsheet headed ‘National Handicap Cruisers (Club)’ with TCFn/ra values ranging from 1.080 to 0.799. I click on ‘Update All’ and these values are transferred into the ‘NewRating’ column. This Spreadsheet appears to conform to the NHC2014 specification, and manually calculating the new ratings from the RYA spec gives the same values (up to TCFn anyway).
The difference between the resulting new ratings might be quite significant. Is the internal version of NHC2014 different to the corresponding spreadsheet that appears when using External/Debug?
Are you able to say when clubs move to the NHC system whether they tend to use the internal system, the External/Debug spreadsheet, or NHC2015?
Again, grateful for your help.
Chris.
Hi Chris,
The internal and the external in default mode should produce identical results. If they don’t please email me the Sailwave file .blw to Jon@Sailwave.com. And I’ll have a look for you.
To the best of my knowledge the majority using Sailwave with NHC are using NHC2014. But of course they don’t have to tell me they can use either. Or even their own variation. It is possible to modify the constants of the internal which is described in this forum but you have to deliberately create a file to do this so you can’t do it accidentally.
Jon
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Jon Eskdale
07530 112233
Skype “eskdale”
Hi John,
While I was checking that I was still getting different TFCn/ra’s, I noticed that on ‘internal’ the side bar and column headings show NHC1 and give the lower spread in TFCn/ra’s, while on ‘external/debug’ they show NHC3 and give the greater spread in values. That will probably tell you something about what I’m doing wrong here.
Thanks for the reassurance that most are using NHC2014. I’ll do the same for now.
I’ve sent you the .blw file just in case you need it.
Thanks again,
Chris.
Hi Jon,
Many thanks for your help over the weekend, it was really appreciated.
The problem I had stems from my use of Excel 2007 and Microsoft’s change of function name ‘STDEVP’ to ‘STDEV.P’ in later versions of Excel. I changed the function name back to STDEVP in cell S51 of template SWNHC2014, and all is now well.
Thanks again for your patience.
Chris.