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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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Raja Muda Selangor 2025 - Pangkor to Penang

Welcome back on board your J-109 for our second online offshore race in cooperation with the Raja Muda Selangor International organisation – an 80nm trip from Pangkor north up the Malacca Strait to Penang.
Race #1962
INFO by brainaid.de
J-109 PARTICULARS
WX Updates:
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Ranking: RMS - SYC
Race starts: Nov 17th 04:00 Registration will open soon

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Raja Muda Selangor 2025 - Port Klang to Pangkor

Sailonline is delighted to be able to offer online sailors an opportunity to once again compete in all three of the offshore races of the Raja Muda Selangor International race week, organised by the Royal Selangor Yacht Club in association with the RORC, and commencing with a 75nm trip from Port Klang to Pangkor. This year we will be racing this race, and the other two, which together will count towards our Sailonline Raja Muda Series (RMS), in J-109s.
Race #1961
INFO by brainaid.de
J-109 PARTICULARS
WX Updates:
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Ranking: RMS - SYC
Race starts: Nov 15th 04:00 Registration Open!

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Africa by Sea 2025 - Suez to Port Said


When Napoleon (briefly) occupied Egypt at the turn to the 19th C, he ordered his expedition’s Directeur des Ponts et Chaussées, Jacques-Marie Le Père, to evaluate the ancient, derelict, infilled course of a Ptolemaic canal connecting the Red Sea to the Nile via the Great Bitter Lake, versus a new canal to the Mediterranean directly. Neither were considered feasible – locks to climb a pauvre-surveyed 10m sea-level difference, or continuous dredging of the Nile, would both be equally financially prohibitive. Fifty years passed before the unlikeliness of Le Père’s survey finding was challenged and a French Compagnie Universelle du Canal Maritime de Suez obtained a 99-year concession from the Khedive of Egypt, Said Pasha, to construct and operate a canal from the Red Sea to the Mediterranean, much against the will of the Ottoman Sultan, Abdulmecid I (the Pasha’s nominal overlord), and the wishes of the (Irish) British prime minister, Lord Palmerston. The year was 1859, the very number of this race (planning, dear boy, planning!), which, despite the canal’s double-super-tanker gauge and lack of locks, is strictly prohibited IRL. 85nm in Fareast 28Rs to complete your circumnavigation of Africa!
Race #1859
INFOby brainaid.de
Fareast 28R PARTICULARS
WX Updates:
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Ranking: SYC - ABS
Race starts: Nov 12th 17:00 Registration Open!
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Round Hong Kong TIMED Race 2025

This month’s TIMED race takes us to the hectic, bustling sea lanes of the South China Sea for a 118 nm race beginning and ending in Hong Kong rounding several of the 260 nearby islands along the way. The boat for this race is the South African built Cape 31. 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 #1964
INFOby brainaid.de
Cape 31 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ4 - TRCH - SUPSOL - SYC
RACE CLOSE: Saturday,
22 November at 23:00 UTC
Race starts: Nov 09th 12:00 Registration Open!
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Fernando de Noronha to Faroe 2025

The RWW Series concludes with a spectacular journey from Fernando de Noronha to the Faroe Islands, a legendary destination in the wild North Atlantic. Panning 4,100 nautical miles, this leg will be a true test of endurance, strategy, and sheer determination. Also the penultimate leg of the 2025 Ocean Championship, it’s your chance to prove your mettle against the sea, the wind, and yourself. We’ll be racing aboard the Ragamuffin 100, a vessel built for speed and challenge — demanding planning, precision and grit from every sailor on deck. Do you have what it takes to master the Northern Atlantic?.
PRIZE: SMPF
Race #1960
INFO by brainaid.de
Ragamuffin 100 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RWW - OCQ4 - OCCH - SUPSOL - SYC
RACE CLOSE: Monday,
November 24 at 2300 UTC.
Race starts: Nov 03rd 11:00 Registration Closed
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Sinbad by Balloon 2025 - Carnarvon to Dondra


From here, our home in Bharatavarṣa is now north west of us – said Sinbad to his fellow balloonists. Perhaps we can ride the wind first further north, and then catch the winds that every year bring the rain, perhaps not. It’s 2600nm and we could be aloft awhile, so, Master el-Quarters, victuals only, no sandbags, provisioning the giant hamper. It will be not a picnic!
Race #1886
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - SBB
Race starts: Oct 15th 11:00 Registration Closed
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SYC Ranking

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