Facebook

Login

Support Sailonline

If you haven't already - join the SAILONLINE YACHT CLUB!

Please also consider making a donation - all amounts are greatly appreciated!

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:

Africa by Sea 2025 - Port Said to Tangier


Back in the 7th C BCE, pharaoh Necho II may have commissioned Phoenician sailors to explore south down the Red Sea and if possible return north via the Straits of Gibraltar. Herodotus was inclined to dismiss the story as it included reports of the sun standing in the north, which had to be nonsense. Silly old Herodotus, but who cares, 2800 years later we will repeat the feat, but we’ll go the other way round, and not in a galley but in different modern sailing yachts, beginning with the comfort of an IY 14.98 for the first leg of 1900nm from Port Said to Tangier.
Race #1854
INFOby brainaid.de
Italia 14.98 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - ABC
Race starts: Jan 22nd 17:00 Registration Open!
▶ Flash
GO TO RACE

Aden to Goa 2025


Europeans are primarily acquainted with the historical narrative of how spices reached their continent from distant regions. However, the spice trade from Goa to Aden predates the modern era, as detailed in this article. Sailonline is now reversing this route, organizing an eastbound yacht race of approximately 1700 nautical miles across the Arabian Sea for our 21st-century Archer 78 yachts. Wishing you fair winds and may the enticing aroma of spices guide you safely to your destination!
Race #1887
INFO from brainaid.de
Archer 78 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ1 - ARCH - SUPSOL - SYC
Race starts: Jan 20th 17:00 Registration Open!
▶ Flash
GO TO RACE

Lake Namtso Ice Race


To kick off our annual Ice Yachting Series, we will travel to Tibet and to one of the World’s highest lakes, Namtso, the “Heavenly Lake”, at an altitude of 4720m. Just fly to Gonggar Airport via Kathmandu, and get a taxi to Lhasa where the Dali Lama lives, then hire a truck with guide to take you and your DN and gear a further 200km north across the Nyenchen Tanglha mountains to Xianga where a 95nm triangle will be beaconed out on the ice for your enjoyment. Although like most of the Tibetan lakes, Namtso is a saline sump with no outflows, rest assured it is bitter cold there and ice is guaranteed. Mind the monks, you’ve no PL!
Race #1850
INFOby brainaid.de
DN PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: DN - SYC
RACE CLOSE: Thursday,
January 23 at 2300 UTC.
Race starts: Jan 19th 09:00 Registration Open!
▶ Flash
GO TO RACE

Vendee Home - Cape Horn to Olon 2025

Welcome to our 2025 Ocean Race Championships starting off with the classic 6900nm drag race from Cape Horn back to the coast of Brittany leading or following the boats of the Vendee Globe fleet. A new polar from the board of the BNH Design Partnership is being made available to you for this one, in the hope that aboard her you too will be able to cover 600nm in a day when the conditions are right! It's winter outside, so like the IRL sailors, enjoy and stay inside!
PRIZE: SMPF
Race #1874
INFO by brainaid.de
IMOCA 60 Foil v2 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ1 - OCCH - SUPSOL - SYC
Race starts: Jan 06th 11:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member WRmirekd
  2. Sailonline Yacht Club Member CriticalHippo
  3. Sailonline Yacht Club Member vida
  4. Sailonline Yacht Club Member FreyjaUSA
  5. Sailonline Yacht Club Member rafa
  6. Sailonline Yacht Club Member Satori
  7. Sailonline Yacht Club Member Kipper1258
  8. Sailonline Yacht Club Member Sax747
  9. Sailonline Yacht Club Member CollegeFund
  10. Sailonline Yacht Club Member BRENTGRAY

View full list

Series

Mobile Client

SYC members have the benefit of access to our mobile/lightweight web client!

The mobile client