Analysis of the LOG file: wind alerts and mark creation

The raw data which is available from the pebble app on your is pasted below. It shows the the Wind alerts and Mark creations. I recorded the whole journey with the normal raceQs app as well and the link to that journey is also listed below. Attached are snapshots of the mark creations.

Mark creations
In general, the mark creations work quite well. Only WM-12:56 and LM-12:44 are way off for which I don’t have an explanations, the wind didn’t change that much in that upwind leg.

The windward marks (WM) are mostly pinnend between the TOP mark and offset mark. I think the app just caclucates the Highest point sailed according to the wind. I think this is accurate enough since offset marks are  100 meters away at most. In an outerloop course, this method could fail however.

The use of mark creations is to give automatic calls for layline. However I haven’t seen any lay-line notification on my pebble. It is possible that i Missed all of them or they never showed.

Then there are the Pin-POS and RCB Pos. It is only showing the last recorded position, however for replay purposes i would appreciate if the previous positions are logged as well. For replay purposes it would also be nice to show exactly when the start was.

Wind alerts
I have copied the wind alerts to excel and did some analysis. I removed those wind alerts which occured while we were not racing. Te starts took place at 12:04, 13:24, 14:18 and 15:17. I had to remove a lot of windalerts. Next time I will reset the timer so the apps isn’t in race mode. I think the app isn’t recording windalerts when not in race mode.

The wind direction was varying between 22 and 340. Since the wind angle was varying of the north, I adjust the wind angle. So -20 degreees means wind angle of 340. The graphs are display the wind angle and changes.

Things noticed:

• Well. The log says wind Adjust by +5 from 1 to 9. But 9-1=8. I recalculated the wind alterations. The calculated wind alternations only seem to match on 11 of  66 wind alerts.
• The peak at 15:22 is realy strange. Though it was the first tack of a new race, the wind direction isn’t calculated correctly.
• According to the log, the wind was very shifty, however in reality we had a very stable wind.

My opinion on the windalerts is that they are too unstable. They are not accurate enough to base your tactics on.

Replay of races:

http://raceqs.com/tv-beta/tv.htm#userId=1018650&divisionId=40671&updatedAt=2016-05-28T16:03:22Z&dt=2016-05-28T11:18:47+02:00..2016-05-28T18:03:27+02:00&boat=DG%20press&model=F18

Log from phone

version: Not yet retrieved from watch.

platform: aplite

model: pebble_orange

language: en_US

firmware: 3.12.1.

pebbleGuid: 6b13997627959792f040fe4aa3bead07

boatLength: 12

bowOffset: 8

windAlerts:

11:50:33 Manual set to 339

11:53:08 Manual set to 3

11:53:20 Manual set to 360

12:06:15 H (S) of -5 to 355

12:06:46 L (S) of 5 to 1

12:08:26 L (P) of -8 to 357

12:08:55 H (P) of 5 to 1

12:12:46 H (P) of 5 to 9

12:12:55 L (P) of -5 to 4

12:25:29 L (S) of 10 to 4

12:25:53 H (S) of -13 to 351

12:26:34 L (S) of 7 to 359

12:27:40 L (S) of 6 to 9

12:28:02 H (S) of -7 to 1

12:30:15 H (P) of 8 to 13

12:30:47 L (P) of -5 to 3

12:33:48 H (P) of 11 to 10

12:34:34 H (S) of -6 to 4

12:35:15 L (S) of 7 to 7

12:35:28 H (S) of -5 to 360

12:45:38 H (S) of -7 to 0

12:45:39 L (S) of 6 to 6

12:50:33 L (P) of -14 to 356

12:50:33 H (P) of 9 to 5

13:05:08 L (P) of -6 to 5

13:07:34 H (P) of 17 to 25

13:07:58 L (P) of -9 to 16

13:08:58 H (P) of 16 to 29

13:09:13 L (P) of -9 to 22

13:09:46 H (P) of 10 to 26

13:10:14 L (P) of -10 to 16

13:10:25 H (P) of 6 to 22

13:11:08 H (P) of 5 to 31

13:12:09 H (P) of 5 to 31

13:29:08 L (P) of -29 to 0

13:29:23 L (P) of -5 to 358

13:29:56 H (P) of 7 to 5

13:37:24 H (S) of -13 to 356

13:37:25 L (S) of 6 to 2

13:37:55 L (S) of 5 to 4

13:40:21 L (S) of 6 to 7

13:41:05 L (P) of -17 to 353

13:41:13 H (P) of 13 to 5

13:51:45 L (S) of 6 to 9

13:52:33 L (S) of 8 to 16

13:52:52 H (S) of -9 to 7

13:53:30 L (P) of -5 to 6

14:08:03 H (P) of 21 to 28

14:09:51 L (P) of -5 to 28

14:10:23 L (P) of -7 to 24

14:23:26 L (P) of -19 to 5

14:34:25 H (S) of -5 to 357

14:35:58 L (S) of 7 to 5

14:36:09 L (S) of 5 to 9

14:46:33 H (S) of -6 to 351

14:47:12 L (S) of 6 to 357

14:47:45 L (S) of 5 to 359

14:52:21 H (P) of 5 to 359

14:59:59 H (P) of 17 to 12

15:01:57 H (P) of 17 to 24

15:02:06 H (P) of 6 to 30

15:04:20 H (P) of 5 to 31

15:05:15 L (P) of -10 to 21

15:06:39 H (P) of 5 to 33

15:07:11 L (P) of -19 to 18

15:08:01 H (P) of 15 to 33

15:08:15 L (P) of -6 to 28

15:09:41 L (P) of -10 to 18

15:10:46 H (S) of -64 to 314

15:10:46 L (P) of -88 to 226

15:10:58 H (P) of 7 to 233

15:11:01 L (P) of -5 to 226

15:11:40 L (S) of 31 to 257

15:11:41 H (S) of -15 to 242

15:12:56 Manual set to 12

15:18:20 H (S) of -30 to 342

15:19:13 H (S) of -6 to 340

15:22:02 H (P) of 37 to 21

15:22:03 L (P) of -19 to 2

15:31:31 L (S) of 6 to 5

15:32:50 H (S) of -6 to 359

15:35:10 L (P) of -7 to 359

15:38:42 H (S) of -7 to 357

15:46:27 L (S) of 5 to 3

15:50:47 L (P) of -5 to 346

15:59:03 L (S) of 11 to 358

15:59:23 H (S) of -5 to 355

16:01:45 H (S) of -5 to 357

16:01:50 L (S) of 7 to 4

16:02:04 H (S) of -5 to 356

16:02:46 H (S) of -5 to 352

16:03:40 H (P) of 14 to 6

16:03:41 L (P) of -6 to 0

16:04:47 L (P) of -7 to 357

16:07:58 H (P) of 8 to 358

16:08:40 L (S) of 5 to 5

16:15:27 L (S) of 5 to 7

16:16:18 L (S) of 9 to 15

16:16:45 H (S) of -7 to 8

16:17:13 L (S) of 7 to 20

17:46:52 L (P) of -31 to 343

17:46:52 H (P) of 15 to 358

17:50:12 L (S) of 35 to 33

17:54:28 H (P) of 23 to 57

17:54:28 L (P) of -12 to 45

17:55:05 L (S) of 41 to 86

17:55:05 H (S) of -20 to 65

17:55:16 H (S) of -7 to 60

RCBPos: 51.74422,3.90379

PINPos: 51.74412,3.90029

Pinged_Marks:

WM-15:52: 51.76021,3.89865

LM-15:43: 51.74489,3.90155

WM-15:39: 51.75995,3.89879

LM-15:31: 51.74486,3.90163

WM-15:25: 51.75992,3.89991

LM-14:58: 51.7429,3.90389

WM-14:53: 51.7599,3.89891

LM-14:45: 51.74471,3.90144

WM-14:40: 51.75993,3.89893

WM-14:26: 51.75993,3.89894

WM-14:10: 51.74473,3.90912

WM-13:56: 51.75778,3.89842

LM-13:48: 51.74484,3.90163

WM-13:44: 51.75778,3.89849

LM-13:36: 51.74494,3.90182

WM-13:32: 51.75776,3.89821

WM-13:12: 51.74456,3.90996

LM-13:04: 51.7425,3.90294

WM-12:56: 51.76458,3.90825

LM-12:44: 51.74553,3.90236

WM-12:37: 51.76491,3.90889

LM-12:25: 51.74497,3.90144

WM-12:17: 51.76486,3.90858

Attachments:

You must be logged in to view attached files.

Topic

[Alan Smith]

I need a week to review this report! It’s amazingly complete, thanks.

A couple of comments off the top.

You are correct, it doesn’t generate wind alerts when not racing.

“The log says wind Adjust by +5 from 1 to 9. But 9-1=8.” The log only reports wind shifts of 5 degrees or more, it could change by 1 or 2 degrees without generating a report. 

I’ll try to do a fuller reply to your post over the next few days.

 

[Alan Smith]

 

In general, the mark creations work quite well. Only WM-12:56 and LM-12:44 are way off for which I don’t have an explanations, the wind didn’t change that much in that upwind leg.

I have re-plotted LM-12:44  at   51.74553 , 3.90236, pretty close to the stbd gate. I think you plotted its position incorrectly.

WM 12:56 is indeed a bit off-course. I will see if I can find an explanation.

[Alan Smith]

Further on the position of LM-12:44, it’s a bit upwind from the actual mark. It calculates the mark position as halfway between the point of losing the groove approaching the mark to regaining the groove after the mark. In the case of LM 12:44, analyzing the raceQs track, you lost the groove around 12:43:45 before putting in three jibes approaching the mark You next regained the groove 12:45:40, so it determined the mark at your position halfway between, at 12:44:45. 

There’s always room for improvement in the algorithm and I will bear in mind this scenario in the next iteration. It doesn’t look for the most upwind or downwind position, as it’s a bit tricky, but might be worth the effort.

[Author]

Replies