VMC Predictor

After couple of years practically unchanged, I have recently made some changes to the functionality of my sollog site. The predictor so far has had two functions, COG and TWA which reflect the two steering modes Sailonline has, continue same course or continue same wind angle. Now there is a third function, VMC - Velocity Made Course.

About VMC itself, there are explanations in SOL-related blogs by the legendary 76Trombones and more recently in the solfans blog. In the predictor view it means that you can set the VMC direction in the degrees-box (or leave it empty for VMC to the next mark). Predictor view will then calculate your course using the best VMC to the given direction (or position in the case of mark).

Technically I have chosen the course to be straight (COG steering) between the reported intervals, i.e. for 6 hour predictor the course is calculated to be 15 minutes COG to the best VMC at the starting point, then a new best VMC course is calculated and next 15 minutes will be to that direction and so on. For longer predictors the straight parts are naturally longer.

Other possibility would be to calculate best VMC for each calculation the predictor does but initially I have thought this is a better compromise for possibly using the result for setting DC's (delayed commands) and judging tacks, gybes or polar hops. The VMC predictor can be thought as a "poor mans router". If you have ideas how it could be improved I am interested to hear them as I am not sure if the current implementation is the best possible.

The other change to the site is not about adding functionality but choosing to restrict some features only for boats which are SYC members. As the site doesn't require any login there is no way to know who the user is. However, boats which are not SYC members can't be used as reference boats in the real time statistics and neither is the predictor view available for non-members.

To clarify this change is completely my own idea to encourage people to join SYC and it has nothing to do with SOL management. I personally don't get any money from the SYC membership fees.


Year 2015 statistics

To write at least one blog post per year here's again some statistics from last year, just like I did year ago.. I have chosen to use the race start time to decide which year races belong, so the Christmas to Christmas race which finished this year is included in last years statistics.

Note that these include only fleet races.

The largest winning margins in 2015

In absolute time the largest margins were:
  1. aner59 by 02:02:41 in Christmas to Christmas 2015 after sailing 16 days 09:26:04
  2. karriv by 01:24:10 in Beru to Bora Bora after sailing 8 days 19:26:37
  3. rumskib by 00:53:27 in SWR2014-2015 Leg 3 - Abu Dhabi to Sanya after sailing 24 days 09:59:59
That's right, only two races from all races run last year were won by over 1 hour margin. 

The largest winning margins in percentages were:
  1. A2 by 1.13% in Pacific NW Inshore Race - WX Test 2 after sailing 1 day 16:04:54
  2. karriv by 0.66% in Beru to Bora Bora after sailing 8 days 19:26:37
  3. kenza by 0.59% in Brisbane to Keppel Tropical Yacht Race 2015 after sailing 2 days 03:26:58

As these numbers compare the winners margin to second place, I additionally looked how tight the top-10 was. These races have the biggest margin between 1st and 10th in absolute time or in percetages:

The tightest finishes in 2015

In absolute time:
  1. WINSTON_4 by 0.023s after sailing 12:08:26 in AGage 50
  2. karaoke by 0.073s after sailing 09:41:10 in SSANZ Safety at Sea Two-Handed Triple Series 2015 - Race 2
  3. robert1 by 0.212s after sailing 04:33:56 in Canna to Eigg RTI SPRINT 2015
Overall, 5 races were won by margin less than one second and 21 races with margin less than 10 seconds.

In percentages:
  1. WINSTON_4 by 0.000052% after sailing 12:08:26 in AGage 50 (winning margin 0.023s)
  2. karaoke by 0.000208% after sailing 09:41:10 in SSANZ Safety at Sea Two-Handed Triple Series 2015 - Race 2 (winning margin 0.073s)
  3. Exmeromotu by 0.001009% after sailing 20 days 14:40:57 in SWR2014-2015 Leg 4 - Sanya to Auckland (winning margin 18 seconds)
Comparing to last year competition in sprint races has become more tight if possible.

The tightest fleet top-10's were:

Longest and shortest races in 2015

  1. Koshiki PYOC 2015 took 02:24:18
  2. Tiree to Coll PYOC Sprint 2015 took 02:59:22
  3. Tomidake RTI Sprint 2015 took 03:12:37