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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:

Cape Town to Auckland 2024


Welcome to the second leg of this Round The World series 2024. It's also the April edition of this year's ocean race championship. The course is the same as the one sailed in 2023, but this year we sail the iconic Swan 65, as suggested in the concluding RTW race last year.
Prepare yourselves for an epic 30-day journey, navigating through the unpredictable waters of the South Seas. It's essential to take care of provisioning to ensure a smooth and enjoyable race experience. With the longer duration, we anticipate plenty of opportunities for camaraderie, competition, and unforgettable memories.
PRIZE: SMPF
Race# 1789
INFO from brainaid.de
Swan 65 PARTICULARS
WX updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - RTW - OCCH - SUPSOL - SYC
Race starts: Apr 01st 11:00 Registration Open!
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Gladstone Ports Corporation Brisbane to Gladstone Yacht Race 2024

Welcome everyone to the 76th anniversary of the GPC Brisbane to Gladstone Yacht Race , Australia's other classic ocean race. Once again, Sailonline is delighted to offer you the opportunity of virtually racing its TP52 over this challenging 308nm course.
Race #1787
INFO by brainaid.de
TP52 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
RANKING: SYC
Race starts: Mar 29th 01:00 Registration Open!
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Vuelta Isla de Chiloé 2024
Designed by SOLer Hotu Matua in 2010 but barely raced since, this is a 263nm race battling the extreme sea, wind and current conditions around the fabulous landscapes of Chile’s Chiloé archipelago. Previously sailed in our somewhat unsuitable Seacart 30, we’ll venture forth in our slightly more modern, water-ballasted Sun Fast 3300 this time. Keep the hatch closed!
Race #1795
INFO by brainaid.de
Sun Fast 3300 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: Mar 28th 05:00 Registration Open!

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Tyrrhenian Tour 2024

For only the second time in SOL's history we will race 800 nautical miles around the small islands of the Tyrrhenian Sea. Fourteen years ago, as many as 383 yachts took part in the competition, will we match the number of participants this time? So, jump into your Judel Vrolijk 62 and lets get ready to race.
Race #1793
INFO by brainaid.de
JV 62 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ1 - ARCH - SUPSOL - SYC
RACE CLOSE: Wednesday,
April 3 at 2300 UTC.
Race starts: Mar 25th 17:00 Registration Open!
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San Juan Islands TIMED Race 2024

Welcome to the beautiful Pacific Northwest and the San Juan Islands. The Salish Sea is home to five different types of whales including Orcas, making this archipelago one of the best places in the world to see whales in the wild. The Cape 31 is a one-design yacht originally created for racing in South Africa, which has rapidly expanded with fleets around the world. This is a TIMED race, so you may RE-REGISTER HERE to try again, after finishing a run. You will have 13 days and 11 hours to show your skill and decision making after the race opens.
Race #1792
INFO by brainaid.de
Cape 31 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ1 - TRCH - SUPSOL - SYC
RACE CLOSE: Saturday,
30 March at 23:00 UTC
Race starts: Mar 17th 12:00 Registration Open!
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Casey Station to Neumayer Station 2024

It’s late summer now in Antarctica, the sun will still not set, but the Emperor chicks are hatched. Let’s yacht on from Australia’s Casey Station, destination Germany’s Neumayer Station! Our route takes us past Molodezhnaya Stancija, Russia’s self-styled capital of Antarctica, as well as Mirney (RUS), Davis (AUS), Mawson (AUS), Syowa (JAP) and Maitri (IND) down the full length of the continent’s east coast. It’s not much more than 2600nm, so let’s take Brazil’s Amyr Klink’s more stately and very comfortable 29m LOA Paratii 2 for this second leg of our six-leg high latitude adventure!
Race #1765
INFOby brainaid.de
Paratii 2 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: HILAT - SYC
RACE CLOSE: Tuesday,
April 2 at 2300 UTC.
Race starts: Mar 14th 19:00 Registration Closed
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SYC Ranking

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Series

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