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Board » Flag Officers » Race proposals » A new race with a new boat.

Posted by JB Posts 305 Registered at 2013-03-07 08:54:34	2015-07-07 16:22:19 - A new race with a new boat.
	The new race proposal: Bermuda TR/SPRT. It’s a new race that can be run on TR mode or on SPRT one (TR - Timed Race; SPRT (Sprint). After some wisdom words from Piero (thank you, again) I thought that #3 different race paths would give enough flexibility to choose, function of the prevailing winds, namely, the type of race to be run. Pls load/see the attached files: 1 - “Bermuda Map with marks.JPG”; 2 - “Bermuda TR.kmz”. The “KMZ” file type is to be opened with GoogleEarth. Race configuration 1. Turning Marks: BM1 to BM11. Max. Distance: 47,6 nm. Race configuration 2. Turning Marks: BM1, BM3 to BM7, BM9 to BM11 (excluded BM2 and BM8). Race configuration 3. Turning Marks: BM1, BM3 to BM5, BM7, BM9 to BM11 (excluded BM2, BM6 and BM8). The new proposed SOL boat. Since Sydney Olympic games, where she was introduced the 49er is a little and vicious speed monster. Pls load/see the attached file: 3 - “boat_49er.txt” (in qTVlm TWA/TWS column style). Shall we have a try? Up to you and our dear SOL committees to agree. A Big Hug to all. Sail Fair. Attachments boat_49er.txt (12.4 KB) Bermuda_TR.kmz (27.2 KB) Bermuda_Map_with_marks.JPG (200.8 KB)
Posted by kroppyer Posts 346 Registered at 2010-02-05 15:25:55	2015-07-07 17:59:04 - Re: A new race with a new boat.
	The 49er polar you posted seems to be based on datapoints from only 3 angles (at various windspeeds): max VMG, min VMG and twa=90 (not counting twa=0 and twa=180). The (bi)linear interpolation is used to generate more datapoints. (Correct me if I'm wrong) Could you share the original data, or remove the datapoints generated using (bi)linear interpolation. Sol's splining algorithm will probably do a better job estimating the boatspeeds between datapoints. --- Last Edited by kroppyer at 2015-07-07 18:01:28 ---
Posted by JB Posts 305 Registered at 2013-03-07 08:54:34	2015-07-07 18:17:11 - Re: A new race with a new boat.
	Viva Huib. Thank you for your comments. The steps I took to extract and generate the 40er Polar data were basically as follows: 1 - Graphic data extraction from aprox. 1.500 points in #7 TWS curves; 2 - Data Outliers cleaning; 3 - Cubic spline interpolations (only) on the collected data points for the TWA/TWS qTVlm range, and two (only) hand adjustments. I’ll send you a DropBox link with the relevant files for you (please see your e-mail) and wait in this chat for your further comments, please. A Big Hug! Sail Fair.
Posted by kroppyer Posts 346 Registered at 2010-02-05 15:25:55	2015-07-07 20:11:41 - Re: A new race with a new boat.
	The graph from which you extracted about 1500 points seems to be based on about 21 points (not counting twa=0 and twa=180). As sol aims to be realistic, I think we should check the reliability of the source before we present this polar as representing a 49er.
Posted by JB Posts 305 Registered at 2013-03-07 08:54:34	2015-07-09 12:17:24 - Re: A new race with a new boat.
	Viva Huib. Clearing out some aspects by appearance order: 1 - The source for obtaining this new SOL boat Polar data - 49er - was already sent to you and, previously to SRC (e-mails); 2 - The options I’ve took for choosing a particular 49er Polar data were also explained (e-mail). 2 - If during your check you find/found out I’ve used an unreliable data source, let’s hear your fundaments, and please I’ll appreciate your help; 3 - None of the curves used for data points extraction are “VMG” ones (EXCEL file). 4 - Those particular curves were generated - only - after obtaining the original data points (EXCEL file). 5 - As I’ve explained previously, namely here, and reiterate in the present, the number of data points used for extracting the Polar weren’t “#21” but, aprox. #1.5000 data points from #7 different TWS curves (EXCEL file). 6 - The average number of TWA angles per TWS curve used was #106, not “#3” (EXCEL files). 7 - I didn’t use “linear interpolation” (EXCEL file). 8 - Exception made to #2 particular data points (hand corrections applied), every interpolation was made by means of cubic spline process (EXCEL file). A Big Hug from J. Sail Fair.

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