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Profile for jakob

Name jakob
Email Address jakob@sailport.se
AvatarUsers avatar
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 :-))

    ...one of the guys behind the game...
  • Re: Leg 2 IMOCA Global
    Board » Sailonline Race Committee » Races

    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.

    ...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 ?

    ...one of the guys behind the game...
  • Re: NOAA vs SOL weather
    Board » Technical Support

    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.

    ...one of the guys behind the game...
  • Re: OCTOBER 2010 - draft calendar
    Board » Sailonline Race Committee » Race Calendar

    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...


Next Race: 00d 00h 00m

Current Races:

A3 2016 - Leg 9 - Perth to Adelaide
SOL's gift to AGage's memory is the A3 - Agage's Around Australia Series. This race is Leg 9, the last in the series - a race of 1300nm in VO70v4s from the appropriately named Gage Roads off Fremantle to Adelaide. Let us race with Aaron's spirit back to Adelaide.
Race #1060
INFO by brainaid.de
VO70v4 Particulars
WX Updates: 0430 / 1030 / 1630 / 2230
Ranking: A3/SYC
Race starts: Jun 25th 10:00 Registration Open!

2017 40' Series Championship Q1&Q2 Singapore Visit
It's time for the sixth of six races in the 40' Q1 and Q2 Championship!
Welcome to Indonesia and a 365 NM race in one of the 40' available for your choice, from the Island of Natuna Besar to Singapore Harbor. This regatta is based on the course of the Singapore In-Port race back in 2009.
There are three boat designs to choose from and each one may NOT be used more than twice during the six race Series, according to the NORof the series
The three boat designs are:
40' Particularsand their official polars are here, just recently uploaded by "sailonline":
40' Polars(as a zip file)
Before you choose the boat design, log in with the "Guest" boat (Username=guest/Password=guest) so you can view the predicted winds to help you choose the best boat/polar for the upcoming race. Once you have chosen to register a boat design for this race, it cannot be undone!
Choosing the same boat design more than twice will get you disqualified from this race!!

View this list to see what boats you've already used:
Race # 1059
INFOfrom brainaid.de
WX Updates:
0430 / 1030 / 1630 / 2230
40Q1&2CH –SYC
RACE CLOSE: Wednesday, June 28 at 15:00:00 UTC
Race starts: Jun 23rd 02:00 Registration Closed

Red Dot 2017 - Leg 3 - Alaska to San Francisco
Inspired by Matt Rutherford's single handed circumnavigation of the Americas, and proposed by SOLer Renegade, Sailonline is racing the course in 5 legs. This is Leg 3 - 2,954nm from Barrow, Alaska to San Francisco, California.
Race #1030
INFO by brainaid.de
SuperMaxi 100 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
ALT. CLIENT: Classic
Race starts: Jun 11th 18:00 Registration Open!

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