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Profile for jakob



Name jakob
Email Address jakob@sailport.se
AvatarUsers avatar
Posts364
Board Signature
...one of the guys behind the game...
  • 2011-06-06 06:56:28
    Re: IMSYC 2011
    Board » General Discussion
    You people are fantastic! What enthusiasm and engagement!!! I will try to get some students to this thread. :-)
    ...one of the guys behind the game...
  • 2011-05-02 06:35:10
    Re: IMSYC / SOLstice Cup
    Board » General Discussion
    You find them in Homework set 5 and 6.
    ...one of the guys behind the game...
  • 2011-05-02 06:08:28
    Re: IMSYC / SOLstice Cup
    Board » General Discussion
    ...and if you want to play around with hull shapes etc to investigate effects on CP, trim, stability etc you might want to try the msy_hydrostatics-code that I put on the same web-page. The code lets you import hull shapes and then stretch them in various ways :-)
    ...one of the guys behind the game...
  • 2011-05-01 18:35:20
    Re: IMSYC / SOLstice Cup
    Board » General Discussion
    Regarding IMSYC: If you are interested in the rule for the IMSYC race 2011 you can find it here http://www.kth.se/polopoly_fs/1.47075!IMSYC-66%20rule.pdf
    I have about ten students designing boats for the race :-))

    /Jakob
    ...one of the guys behind the game...
  • 2011-01-15 12:33:46
    Re: Leg 2 IMOCA Global
    Board » Flag Officers » Races
    Hi

    As always in SOL: Changing course, maps etc in the middle of a race is generally a bad idea. Main reasons are:
    1) the communication problem. How do we make sure that we reach all boats with the info?
    2) We have very little control over when the changes become visible in the clients. Often, a clear-cache is needed (or long time).

    I vote for not changing courses etc unless absolutely vital.

    /Jakob
    ...one of the guys behind the game...
  • 2010-12-06 19:48:24
    Re: NOAA vs SOL weather
    Board » Technical Support
    ...well you should be careful with those softwares... especially when there is a Sailplanner available for free ;-)
    ...one of the guys behind the game...
  • 2010-12-05 20:58:26
    Re: NOAA vs SOL weather
    Board » Technical Support
    Hi all,

    You are basically all correct :-) I am the first to admit that there are many ways of doing this and that we did not spend weeks of thinking when choosing algorithm - but it works. Also (Hubert) the game winds will only correspond exactly with the GFS-forecasts when the time is exactly the time of a certain forecast frame and the point of the "observation" is exactly that of a forecast nodal point. Thus, colour coding would not be of any use at all...

    Why this attention? Is it just curiosity or weather-rounting ?

    Regards
    Jakob
    ...one of the guys behind the game...
  • 2010-12-03 16:17:40
    Re: NOAA vs SOL weather
    Board » Technical Support
    Hi

    So, about the interpolation of weather in time and space :-) Maybe some out there is longing for a short one-liner as explanation but I am afraid there is a little more to it… Here is in short the steps we take to get an "observation" (as we call it) at an arbitrary time (called t) and location based on forecasts.

    1) Find the two forecast time steps (here called t1 and t2) surrounding the time t.
    2) In space we simply use linear interpolation (in the 2 dimensions lat/long) of the forecast-data in the 4 closest forecast-nodes in the grib-file. Since the forecast has separate fields, one for northerly wind and one for easily wind we need to treat these entities separately, in our case by using complex notation. We also need to do this for both frames t1 and t2 from step 1 which thus gives us a set of two complex-valued space-interpolated wind speeds, one at t1 and one at t2.
    3) Now we need to interpolate in time as smoothly as we can. We chose to do this using simple shape functions ensuring continuous wind speed and actually in our case continuous time derivatives.

    Now, there are naturally many ways of doing this. One draw-back of this kind of interpolation is that we loose energy. Imagine the situation with constant wind speed but rotating wind direction so that at t1 the wind is due easily and at t2 it is due westly. In our interpolation we would (falsely) get that the wind speed at the time (t1+t2)/2 would be zero.

    Also note that we do not always use the GFS model from NOAA. In particular around Sweden we have more detailed forecasts.

    Hope this helped a little.

    Regards
    Jakob
    ...one of the guys behind the game...
  • 2010-09-19 15:00:56
    Re: OCTOBER 2010 - draft calendar
    Board » Flag Officers » Race Calendar
    Hi.

    We all remember the Irish-rock episode. The problem that time was the unauthorized use of protected brand names. From that point in time SOL has been, and will continue to be, careful and considerate in terms of naming races. However SOL is not by any means scared of racing between locations in the geography where others, IRL or virtually, also race. Until proven wrong SOL is of the opinion that it is totally ok for anyone to race "similar time-similar route" as IRL-races. No-one has ever raised any legal aspects regarding this. However I do want to point out that if SOL administrators (Godesses etc) do not see that a certain race fits the calendar it is up to the community to argue and be sugary :-)) Happy sailing /Jakob
    ...one of the guys behind the game...
  • 2010-06-28 14:46:05
    Re: Rename boat
    Board » Technical Support
    Done :-)
    ...one of the guys behind the game...

Races

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Lake Victoria TIMED Race 2026

This month’s TIMED race takes us inland to Lake Victoria in the heart of Africa. Starting at Rosebery Channel in Uganda sail the AC72v2 on a 196nm course around Bugala Island on the way to the finish line in Tanzania’s Speke Gulf. This is a TIMEDrace so you may RE-REGISTER HEREto try again after finishing a run. You will have 13 days and 11 hours to test your skill and decision making after the race opens.
Race #2018
INFOby brainaid.de
AC72v2 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
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RACE CLOSE: Saturday,
28 March at 23:00 UTC
Race starts: Mar 15th 12:00 Registration will open soon
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SSANZ Round North Island Race 2026 - Leg 4

The final challenge awaits in Leg Four of the Round North Island Series! From Napier, the fleet sets off on a 354 nautical mile run back to Auckland, completing the full circumnavigation where the journey began. Fatigue may be setting in, but this last leg could decide the overall standings. Sailing the fast and responsive Sun Fast 3600, our skippers will need sharp tactics and steady focus to finish the series strong and claim victory!

The start time for this race may change at short notice to align with the real race. The confirmed start date and time will be announced via an in-race “L” flag message — Please monitor race communications closely.
Race #2014
INFO by brainaid.de
Sun Fast 3600 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RNI - SUPBUD - SYC
Race starts: Mar 12th 22:00 Registration Open!
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SSANZ Round North Island Race 2026 - Leg 3

Leg Three of our Round North Island Series, in partnership with SSANZ, keeps the pressure on! From Cook Strait, the fleet turns north for a 187 nautical mile passage up the east coast to Napier. It may look like a quick overnighter, but shifting coastal winds and the ever-lively Cook Strait demand sharp focus. In our responsive Sun Fast 3600s, a proven short-handed racer and powerful downwind performer, tactical decisions and precise timing will make all the difference!

The start time for this race may change at short notice to align with the real race. The confirmed start date and time will be announced via an in-race “L” flag message — Please monitor race communications closely.
Race #2013
INFO by brainaid.de
Sun Fast 3600 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RNI - SUPBUD - SYC
Race starts: Mar 08th 22:00 Registration Closed
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Iceland to the Falklands 2026

Welcome to an all-new route, the first of three Round the 'Old World' of Europe, Africa, Australia and Asia. To give each leg of the ROW a bit of length we'll try to hug the coasts as little as possible, so starting in Iceland our first leg of the series, which will also be the final leg of our Quarter 1 Ocean Championships takes us 7200nm to the Falklands, the full length of the Atlantic end to end. To make sure we'll get it done within the month we'll be sailing our Maxi Trimaran.
Race #2010
INFO by brainaid.de
Maxi Trimaran PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ1 - ROW - OCCH - SYC
Race starts: Mar 02nd 11:00 Registration Closed
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