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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 » Sailonline Race Committee » 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 » Sailonline Race Committee » 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:

Up Helly Aa 2020
A-OI!!! The dark of winter is beginning to lift and across the Shetland Islands the light of fire festivals hastens the arrival of spring. The Up Helly Aa festival in Lerwick is the biggest of them all and so, as is Sailonline's tradition, we shall be racing to Lerwick to (virtually) take part in the Up Helly Aa festivities there which take place this year on Tuesday, 28 January. SAILING NOTE: Gruney may be approached from any direction but must be passed for rounding purposes as indicated on the chart.
Race #1321
INFO from brainaid.de
Elan 410 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
RANKING: SYC
ALT. CLIENT: Classic
Race starts: Jan 27th 11:00 Registration will open soon
New HTML5 Client GO TO RACE

Martinique Sprint 2020
One of the surprising things about France is that you find nice little departments of it everywhere; here, par example, in the Caribbean Sea's Windward Isles. Yes, Martinique is part of the European Union, and for a few Euro coin you can charter an F18 catamaran to explore the beaches along its eastern coast. There's an online race on here as well on Saturday, January 25; just 21.5nm from Île Cabrits to Le Robert. Why not join in?
Race #1313
INFO by brainaid.de
F18 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
SPRCH - SUPSOL - SRQ1 - SYC
ALT. CLIENT:Classic

Race starts: Jan 25th 18:00 Registration will open soon
New HTML5 Client GO TO RACE

3CR - Caen Channel Craic 2020
This 975 NM course first run in 2011 mixes challenging coastal sailing through the Solent with a tricky triangular course across the Celtic Sea before finishing in Normandy.
You are provided with our excellent "Club Swan 50" to do it!
Race #1320
INFO from brainaid.de
Club Swan 50 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
ALT. CLIENT:Classic
Race starts: Jan 19th 16:00 Registration Open!
New HTML5 Client GO TO RACE

South Sandwich Islands TIMED Race 2020
No time to stop off for a quick snack as we hit a truly fire and ice trail round volcanoes and a stationary iceberg in this 93nm TIMEDrace. We sail in our VO70_4's on a course provided by NZL_Scotsman.
RE-REGISTER HEREto race again after finishing a run.
Race #1318
INFOby brainaid.de
VO70_v4 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ1-TRCH-SUPSOL-SYC
ALT. CLIENT:Classic
REGISTRATION CLOSE: Sunday, 26. January at 22:00 UTC
RACE CLOSE: Sunday, 26. January at 23:00 UTC.
Race starts: Jan 13th 12:00 Registration Open!
New HTML5 Client GO TO RACE

Abu Dhabi to Dondra 2020
Almost exactly five years ago, SOL, shadowing a real live ocean race, set a mighty fleet of honed and updated OD65s off on a gruelling voyage from Abu Dhabi to Sanya on the southern tip of China's Hainan Island. A month later, the race closed with half the fleet still out at sea. This year, this January, we re-enact this race, but are putting in a stop halfway, after about 2000nm, at Sri Lanka's Dondra, with the second leg scheduled to start a month later; both to count towards 2020's OCCH series. Fair winds!
PRIZE: SMPF
Race #1308
INFOby brainaid.de
OD65v3 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
OCCH – OCQ1 - SUPSOL - SYC
ALT. CLIENT: Classic
RACE CLOSE: Sunday,
January 26 at 2300 UTC.
Race starts: Jan 06th 17:00 Registration Closed
New HTML5 Client GO TO RACE

Go to race archive

SYC Ranking

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Series

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