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Profile for kroppyer



Name kroppyer
Email Address info@kroppyer.nl
Website URLhttp://sol.kroppyer.nl
AvatarUsers avatar
Posts322
  • Re: Polars
    Board » Technical Discussion
    It is a collection that grows over the years. There are multiple ways we create polars. Sometimes there is enough data online to create reasonable polars, sometimes we have contact with boatowners, sometimes we can get enough data from tracking IRL boats while racing. Usually it's a combination of everything.
  • Re: HOW TO CHANGE THE NAME OF MY SHIP?
    Board » Technical Support
    You can't change your boat name. We can do it for you, send us an e-mail (on the admin@sailonline address) with the new boatname you want.

    --- Last Edited by kroppyer at 2017-12-06 09:11:23 ---
  • Re: swr 14-15 leg1
    Board » Sailonline Race Committee » Races
    Good catch nacrr, it was hidden by accident. I made it re-appear and everything should be back to normal soon.

    You can already find it here:
    http://www.sailonline.org/races/756/leaderboard/
  • Re: WX Release Time Standardisation Suggestion
    Board » Sailonline Race Committee » Races
    We may be able to change the time the weather update becomes active on our server, but we cannot change the time of publication on NOAA's servers. Basically, it means the weather that we will have can be known long before our delayed wx update, effectively not changing a thing at all to the time you need to check the weather and adapt your courses to react to the new forecast.

    We're all aware of the sleep deprivation factor here when using the high resolution weather from the NAM model. SRC is very careful with using the model, and you can be sure that it won't happen too often that two races using different wx updates run in parallel.
  • Re: VOR, Vestas incident & report.
    Board » General Discussion
    Yes Rod, using more realistic nautical charts would hugely improve the educational value of sol wrt navigation. but we have to be careful that sol remains accessible for the masses, not only the ones that are (a) experienced in navigation or (b) willing to invest time in their navigational skills.

    I'm sure there's a middle way that solves this problem: nautical charts, but no requirement to understand every element of it to successfully sail a race (by using our own very simple and clear "you can sail in this area, not in this area"-two-colour-map as overlay for example)

    While sailing on sailonline, I would really like to have some more detail of the region where I'm sailing. There's lots of reefs, shallows, bridges, etc. etc. that we're missing out on. Problem is, when I'm not online, I really like not having to worry about all these things. I'm not able to spend as much time online during the week as I would be able to spend on deck during and actual IRL sail.

    Then of course, there's the technical side: we need a world map where there is a clear divide between "navigable waters" and "running aground" so that the computer can understand. As far as I know, the map we are currently using (GSHHG) is one of the best that is available at reasonable cost (in this case: free). In the best case, the process of changing to another map is a lot of work and needs a lot of testing. We are slowly moving towards a situation where we hope to be a bit more flexible, but its hard work. At some point in the future it may be possible to show some more detail in the map, but there is a lot to do before we get to that situation.

    --- Last Edited by kroppyer at 2017-11-05 10:58:50 ---
  • Re: Crossing the Finish Line
    Board » Technical Support
    Rankings of an individual race are calculated every minute or so. The DTF is updated more often. So it may be the case that the ranking updates and places boat A on #1 and B on #2, just before they finish. Then B overtakes A and they finish. The leaderboard will update DTF, showing #1: A, #2: B, both with DTF 0 (finished), and after a minute, maybe little more, they switch position to reflect that actual finish order.

    I'm not sure how to explain two changes after DTF has reaches 0, but the main idea is that the actual ordering/ranking of the leaderboard is lagging behind a little bit, which usually isn't a big deal, but when people are finishing close together, the leader board need a couple of minutes to settle.
  • Re: RTW 2017/18 Courses
    Board » General Discussion
    I believe leg 1 of SWR was inspired by an IRL course that was in fact never sailed, I think because the race organisers opted for a different course based on the weather forecast. In my own opinion, our SWR leg 1 wasn't really the typical ocean race leg, but having seen the course for leg 2 (admin perks :) ), the next leg will definitely be the typical Southern Europe to South Africa ocean race. And although I'm not part of SRC, I'm pretty sure the other longer legs of our SWR will be implemented as round the world races are typically done. For the shorter legs I'm sure SRC will also look around for IRL course designs, but since start and finish may not be that far apart, there may not be one single 'typical' course, and SRC will need to make a choice as to what sort of course they want to design before things like weather forecasts are available. This is where we are different from IRL race organisers: we can't do last minute changes (based on weather or whatever), because there are just too many sailors on our races, and almost none have sol as their full time job.
  • Re: Discarding ziggy points or… not.
    Board » Sailonline Race Committee » Championships
    You make some good points, let me clarify.

    200 series. In each series I picked 200 boats and had them sail 40 races (for each new series, I picked a new set of 200 boats, but within a series, I used the same set of boats for the 40 races).

    To determine the "true ranking", simulated 1960 more races in each series, totalling 2000 races in each series, but only the first 40 are used in the analysis.

    Why 40 races? because I thought series with more than 40 races were not too interesting to look at. But yes, my results for a series of x races and that for a series of x+1 races are not at all independent.

    About DNF and bad races, you are correct. Let me give a more accurate description of the probabilities, solving the problem:
    - the probability of having a bad race assuming the boat finishes (between 5 and 15%)
    - the probability of scoring a DNF (between 2 and 8%)
    The actual implementation works as follows: flip a (weighted) coin to determine if the boat scores a DNF, if the boat doesn't score a DNF, flip a different weighted coin to decide between a good and a bad race.

    Although I'm not really surprised by the results, I cannot really explain what's going on either. I'm continuing to investigate.
  • Re: Discarding ziggy points or… not.
    Board » Sailonline Race Committee » Championships
    This is not a rigorous scientific result, but I believe it makes a convincing argument in favour of having one race discarded in a 6 race series.

    The 40' series is a different thing all together. The whole limited boat choice makes it a very different type of race and discarded races have side effects that are not observed in normal race series. The following analysis is not applicable to the 40' series.

    I have simulated 200 series of 2000 races each with 200 boats. I have used to final ranking in the series as the "true" ranking, and after that I have only looked at the first 40 races and compared them to the "true ranking". I have modelled the boats as follows: in a race they have some performance 0-100%. 100% means they couldn't possibly have sailed faster, 0% means they didn't finish. Each boat is defined by 6 parameters:
    - the mean performance when all goes well (90 to 100%)
    - the standard deviation of performance in a good race (0.4 to 2%-point)
    - the mean performance in a bad race (something breaks/goes wrong, but boat can continue racing and finishes): values between 50 and 90%
    - the standard deviation for performance in a bad race (2 to 10%-point)
    - the probability of having a bad race (between 5 and 15%)
    - the probability of scoring a DNF (between 2 and 8%)

    For every simulated series I "created" 200 new boats by picking for each parameter a value uniformly at random in the specified range.

    As a measurement of how good a ranking is, I took the Spearman's footrule distance from the "true" ranking (obtained after 2000 races). The larger this distance, the larger the "ranking error". When this distance is 0, the ranking is exactly equal to the "true tanking".

    Attached is a figure (linear scale and log scale) showing how this "ranking error" decreases as the number of races increases (as you would expect). Up to about 5 races in a series, we see that ranking with no discards gives on average the best ranking. Between about 5 and 12 races in a series, one discard gives a better ranking. When there are 24 or more races in a series, allowing 3 discards yield better rankings than allowing 2 discards.

    How I modelled the boats may not be very accurate. Changing the model and the number of boats in the fleet will likely have an effect on where these "switch-overs" are exactly, but I am confident that the general behaviour is consistent: as the number of races increases, the number of discards should increase as well, but slower.
  • Re: Discarding ziggy points or… not.
    Board » Sailonline Race Committee » Championships
    I'm not SRC, but I think I'm qualified to talk about this. I can join the discussion, but not make the decisions.

    I don't understand your argument João. You're saying one discard in 6 races has a larger impact that 1 discard in 30 races? I agree. Question is, is it a good or a bad impact? Your suggestion of not discarding Series points seems to indicate that you think discards are a bad impact, but I don't understand why you think that is the case.

    I like to believe that discards are there to eliminate the element of "bad luck" from the racing. Having bad luck one more time than the opponent shouldn't give you a 100 point disadvantage, so that's why you allow skippers one bad race every 5 (or so) races. If you have a bad race more than once every 5 (or so) races, you deserve to be punished.

    In a race like the VOR, where we have 7 competitive boats, the punishment for a DNF (because of damage for example) is relatively small, but in a big race on SOL, with 200 entrants of which 100 competitive, the punishment if a DNF (because of connection failure for example) is much larger. So without discards, bad luck had a massive influence of the rankings on SOL compared to some IRL races. The VOR doesn't have discards (at least not last time) because the penalty of bad luck is not too bad meaning there is a reasonable balance between doing well in normal races and managing the risk of having a bad race.

    Anyway, this is an interesting topic, I might do some experimenting like you did in your spreadsheets but on a larger scale. I'll keep you posted when I do.

Races

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Current Races:

Sydney to Mooloolaba 2018
Its January, so Sailonline has decided to race the 468nm from Sydney, on Australia's SE coast, north to the holiday, surfing and sailing centre of Mooloolaba on the Sunshine Coast of Queensland.
Race #1107
INFO by brainaid.de
60ft Trimaran Particulars
WX Updates: 0430 / 1030 / 1630 / 2230
Ranking: SYC
ALT. CLIENT:Classic
Race starts: Jan 23rd 02:00 Registration Open!
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2018 40' Series Championship Race 1 - Sardinia Cup
Welcome to a new season and the first of twelve races in the 2018 40' Series Championship!
We will use the Sardinia Cup 223 nm racecourse round Sardinia in the Mediterranean Sea to test your skills.
It seems that there's a lot to see here, so watch your Google Earth feed closely
HOW TO BE DISQUALIFIED!!
READ THIS CAREFULLY !!!!

Race # 1111
INFOfrom brainaid.de
The Chart is NOT available for this race !
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
40CH - SYC
ALT. CLIENT:Classic

Race starts: Jan 19th 11:00 Registration Open!
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Rio In-Port TIMED Race 2018
Many years ago, when the Volvo Round-The-World yachts were 70 foot long and not restricted much in any other way, SOL organized their own little round-the-cans race outside the harbour of Rio de Janeiro. To start our 2018 series of TIMEDRUNS , we are setting those cans out again for you, and this time they will stay in the water for 20 days for all comers to try as often as they wish to set a best time. We won’t be racing a VO70 though, but the slightly more sedate X35, which, given that the course is some 80nm in length, will mean you will be confronted by a change of forecast or two during your runs. You’ll have to take a view!
RE-REGISTER HERE to race again after finishing a run
Race #1106
INFO by brainaid.de
X-35 OD Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
RANKING:
TRCH-SUPSOL-TRQ1-SYC
ALT. CLIENT: Classic
RACE CLOSE: Thursday,
25 January at 2300utc
Race starts: Jan 05th 11:00 Registration Open!
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SWR 17/18 Leg 4 - Melbourne to Hong Kong
After celebrating Christmas and New Year it is time for Leg 4 of this fantastic Sailonline World Race 2017/18.
After leaving Melbourne on this (about) 5.500 NM course, we will leave the Solomon Islands, Papua New Guinea and the Philippines, all to port
And remember, once again we'll have to choose the best way to cross the Doldrums
Race #1104
INFOfrom brainaid.de
OD65v3 Particulars
WX Updates: 0430 / 1030 / 1630 / 2230
Ranking: OCCH-OCQ1-SUPSOL-SWR-SYC
ALT. CLIENT:Classic
Race starts: Jan 02nd 03:00 Registration Open!
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