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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...
  • 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...
  • Re: IMSYC / SOLstice Cup
    Board » General Discussion
    You find them in Homework set 5 and 6.
    ...one of the guys behind the game...
  • 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...
  • 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...
  • 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...
  • 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...
  • 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...
  • 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...
  • 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...
  • Re: Rename boat
    Board » Technical Support
    Done :-)
    ...one of the guys behind the game...

Races

Next Race: 00d 00h 00m


Current Races:

Flight of the Godwit - Wellington to Hegura 2024


Bar-tailed godwits can fly about 6500 nm without resting - further than any other known bird. They fly at about 32 knots, which means this 5000 nm leg would be done in a week. We won't be able to accomplish that, although we will sail our fast Maxi trimaran. This race is the first of three legs reflecting the migration routes of the bird, and the third leg of the 2024 Ocean Race Championship. The voyage promises to be not only a test of skill and strategy but an immersive experience in the beauty of the archipelagos of the western Pacific. Join us as we push the boundaries of seafaring prowess on this epic adventure. Let's fly like a godwit!
PRIZE: SMPF
Race #1763
INFOby brainaid.de
Maxi Trimaran PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ1 - GWT - OCCH - SUPSOL - SYC
Race starts: Mar 04th 11:00 Registration Open!
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Sea of Cortez 2024

Welcome to the breathtaking Sea of Cortez, a UNESCO World Heritage site! Prepare for an unforgettable 700nm journey starting from Cabo San Lucas and culminating in the serene Baia de la Paz. The ever-so-popular Xp-55, crafted by Denmark's Niels Jeppesen, will be our trusty companion in this exciting adventure. Don't miss out on the opportunity to witness the stunning sights along the way—be sure to bring your binoculars and cameras for an extra dose of awe and wonder!
Race #1786
INFO by brainaid.de
Xp-55 PARTICULARS
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC
Race starts: Mar 02nd 05:00 Registration Open!
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Simonstown to St Helena 2024

Since the weather in the northern hemisphere is not pleasant, we stay in the climate of southern Africa to hold another race from the All-Round Championship series. Our Gunboat_90s will have to cover the 1700nm route from Simonstown to the island of Saint Helena, which became the last haven of Emperor Napoleon.
Race #1785
INFO by brainaid.de
GB90 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ1 - ARCH - SUPSOL - SYC
Race starts: Feb 26th 17:00 Registration Closed
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San Diego to Puerto Vallarta 2024

Set sail for adventure with Sailonline's third epic voyage, in collaboration with the San Diego Yacht Club! Prepare for the ultimate challenge: a 1000-nautical-mile race to Puerto Vallarta along the stunning Mexican Riviera. As the real fleet ventures forth, we'll be right beside them, guiding our Santa Cruz 70s toward the sun-soaked shores of Puerto Vallarta! Are you ready to join the excitement?!
Race #1784
INFO by brainaid.de
Santa Cruz 70 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
RACE CLOSE: Wednesday,
March 6 at 2300 UTC.
Race starts: Feb 24th 20:00 Registration Closed
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