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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

Next Race: 00d 00h 00m

Current Races:

Melbourne Osaka Cup Double-Handed Yacht Race 2025

Welcome once again to what these days is Sailonline’s almost annual virtual Melbourne to Osaka Yacht Race. In real life, this double-handed 5500 nm race between these two sister cities, one deep in the southern hemisphere, the other high in the northern hemisphere, is run every four to five years, and this year is such a year. So, this year’s online version is in sync with the Melbourne Osaka Cup 2025 organised by the Ocean Racing Club of Victoria (ORCV), and the Sandringham (SYC) and Osaka Hokko (OHYC) yacht clubs. We’ll be racing the well-known First 40, a popular size of boat which should be a good match for many of the boats entered in the real race. With the doldrums unavoidably lying across our course, you can expect to be at virtual sea for at least a month!
Race #1669
INFO by brainaid.de
First 40 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: Mar 16th 06:00 Registration Open!

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Channel Islands 500 Yacht Race 2025


Prepare for an exhilarating offshore challenge in the Channel Islands 500 Yacht Race! Collaborating with the Newport Harbor Yacht Club, Sailonline brings you a 500-nautical-mile test of skill, speed, and strategy. Starting in Santa Barbara, you’ll navigate between Santa Cruz Island and Santa Rosa Island, rounding three marks before finishing in San Diego. Our SOLers will be competing in their Melges 40s, a high-performance offshore racer designed by the Botin partnership. Who will conquer the Pacific and claim victory? Set your course and race for glory!
Race #1899
INFO by brainaid.de
Melges 40 PARTICULARS
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC
Race starts: Mar 14th 22:30 Registration Open!
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Lake Ladoga Ice Race


For our second race of the 2025 Ice Yachting series, we shall risk disturbing another sect of monks, these of the Orthodox persuasion rather than Buddhist. Good ice is often found in remote places, and remoteness breeds contemplation, and Valaam Island at 61.3N in the north east corner of Lake Ladogo is as remote as it gets. Surrounded by pristine ice in winter, we find there one of the great monasteries of Russian Orthodoxy. So, get your visa’s, fly to St Petersburg, take the N-121 north to Vladimirovka, and get your DN-skates on for another no-PL monk-minding race, this time of 110nm in length, out around Valaam, then Derevnya, to finish near Berezova.
Race #1851
INFOby brainaid.de
DN PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: DN - SYC
RACE CLOSE: Friday,
March 14 at 2300 UTC.
Race starts: Mar 10th 09:00 Registration Open!
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Walyalup Sprint 2025


Once upon a time, aboriginal legend has it, the country of the Whadjuk people extended west from the present day Fremantle shoreline out to Rottnest island, but Walyalup as they called it was lost to the sea, and this sprint takes you across those inundated lands, round reefs and across shoals, 25nm in a Dufour 34. For the Walyalup, March fell in Bunuru, the hottest season of the year, which meant living near the water. Expect hot easterly winds, and cooling afternoon sea breezes with little to no rain. Perfect weather for a sail.
Race #1897
INFO by brainaid.de
Dufour 34 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
SPRQ1 - SPRCH - SUPSOL - SYC
RACE CLOSE: Wednesday,
March 12 at 2300 UTC.
Race starts: Mar 08th 03:00 Registration Closed
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Tristan da Cunha to Coronation Island 2025

The adventure continues as we embark on the second leg of the RWW series, racing from Tristan da Cunha to the remote and uninhabited Coronation Island, NO, Elephant Island. Nestled between the Scotia Sea and the Weddell Sea, both island were named by 19th C British whalers. Prepare for a thrilling journey through the Roaring Forties and Furious Fifties, where relentless winds and challenging seas will test the mettle of every crew. This leg will be sailed aboard the historically iconic Steinlager II and is part of the prestigious OCCH 2025 series. The RWW series ranking will be determined by each team's best 7 out of 8 race results, so every moment counts! Are you ready to face the ultimate test of skill and endurance?
PRIZE: SMPF
Race #1890
INFO by brainaid.de
Steinlager II PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ1 - RWW - OCCH - SUPSOL - SYC
Race starts: Mar 03rd 11:00 Registration Closed
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Sinbad by Balloon 2025 - Dondra to Toamasina


Above you see a stratospheric balloon, that if only we had gribs at that altitude would get blasted along quite rapidly and predictably. Alas we just have our SOL balloon that sails rather lower to the sea and that we have crossed the Atlantic in, west to east, last year for the first time in the southern hemisphere. So much fun was had by all, that this year we will attempt the Indian Ocean, but in four legs. Another great piece of fiction, the voyages of Sinbad By Balloon not magic carpet, although you may need a bit of magic to make any progress at times. Pack your wicker basket full for your first leg of at least 2300nm from Sri Lanka to Madagascar; it’s not a picnic hamper, you could be in the air for longer than you hoped!
Race #1883
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - SBB
RACE CLOSE: Tuesday,
March 18 at 2300 UTC.
Race starts: Feb 05th 11:00 Registration Closed
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  1. Sailonline Yacht Club Member Patrick70119
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