Support Sailonline

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

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

Board » Technical Support » distance to go

Page: Previous 1 2

That's all indifferent since the nonsense numbers lead us all astray. Who cares if it all makes sense when we "get close." Why play along at all. Sheeeze...
evilonod - I can sympathise with your frustration, but rest assured there is no-one getting any advantage here. It really is all about the shape of the globe and how SOL's calculations are made.

Please don't give up on us!
I believe I have now found the root cause of this problem. I have described it in my blog:

As for the DTF calculations, how about simply calculating GC bearings to the next couple waypoints, then using GC distance to the best WP based on bearings + rounding direction. I suspect this may lessen server load as well. (see pic)
I have also tried to explain the DTF calculation in more detail in my blog, check the post here:


As I say in the post, the DTF calculation is run every 15 seconds for each boat, so changes to that code have to be made very carefully not to cause the server too much load.

However, that doesn't mean that there will not be improvements in the future. It just means that the changes have to take into account also other things than only always getting the best possible DTF for the boat.
Is it not possible for each player (sailor ?) to merely run the measuring caliper tool, in Great Circle mode, between the next turning mark and the current position of any boat (including his own) in which he has an interest?
I just do not understand the cause of all this worry over such a trivial problem.
Congratulation to Markku H. for solving the causes of the SERVER'S problem, but it is really not a problem to the SAILOR.
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
> the DTF calculation is run every 15 seconds for each boat

This is unneeded, do a proper distance calculation every 16 steps, and use increments (VMC * timestep) inbetween.

That means only one in 16 boats gets a full calculation for a given timestep.

The same could be done for roundings, maybe.

--- Zuletzt bearbeitet von outlaw am 2013-01-02 18:33:23 ---
To do that the VMC (and the course which to calculate VMC for) should be calculated for each boat every 15 seconds so it's not clear if it's easier to it that way.

The VMC, VMG etc numbers you see at the client are calculated at in your own computer and are thus "cheap" for the server but on the other hand are not available there directly.

It's good to have different ideas how to improve the calculation but as Rod wrote earlier I don't see it as a major problem now.
Recent experience at RTW2014-leg4. The "rounding line" ref. hmm for Cape Horn has a limit at 83S & 34W. Why not move that limit to say 65S & 64.2W or the exact W pos. on the "rounding line". Wouldn't that be a simple improvement for the boat position at the Horn specificly.

Rgds Hans

Page: Previous 1 2

Please login to post a reply.


Next Race: 00d 00h 00m

Current Races:

Susan Hood Trophy Race 2022

Lake Ontario Offshore Racing (LOOR) welcomes racers to the second virtual Susan Hood Trophy race. This is a 75nm weekender on western Lake Ontario starting and finishing at the Port Credit Yacht Club (PCYC) via Niagara and Burlington, and is one of two that will count towards special Sailonline's LOOR Series medals. As our Beneteau/First 36.7 managed the course so well last year, we shall race her again!
Race #1574
INFOby brainaid.de
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC - LOOR
Race starts: Jun 03rd 23:45 Registration Open!

▶ Flash

Susac X2
Welcome to the beautiful calm waters of the Adriatic Sea for the virtual running of the Susac X2 race which is a real-life race organized by the JK Mornar Sailing Club based in Split, Croatia. Although we, unfortunately, aren’t running this magnificent race with the real fleet this year, we hope to make this possible in the coming editions. This amazing race is a total of 91 nautical miles which consists of rounding the beautiful island of Sušac. Our SOLers will be racing around these amazing waters in none other than our great Seascape 18s. Be sure to bring your binoculars for this one as with such beautiful surroundings you will definitely need them!
Race #1586
INFO by brainaid.de
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC
Race starts: May 27th 14:00 Registration Open!

▶ Flash

Vasco da Gama Ocean Race 2022

Point Yacht Club welcomes Sailonline to the 2022 running of the classic Vasco da Gama Ocean Race. This race is the oldest established international sailing event in South Africa and traditionally starts in the bay of Maputo, the old Portuguese colonial capital of Mozambique and finishes in Durban. Last year, and now again this year, the race was/will be from Durban to East London - circa 250nm in native Cape 31 speed machines.
Race #1573
INFO by brainaid.de
WX Updates:
0430 / 1030 / 1630 / 2230
May 29 at 2300 UTC.
Race starts: May 22nd 08:00 Registration Closed

▶ Flash

San Francisco to New York 2022
Cornelius Vanderbilt, who made his money - that his descendants enjoyed to spend sailing and racing yachts - by recognizing that getting from the East Coast to the West Coast of the USA was best done by rail, would have been more than a little amused to see SOL organizing yacht races over the very route by water he made redundant. It's about 13,000 nautical miles, which compares with less than 3000 statute miles by train! Six years ago, the best SOLers managed to complete the passage from San Francisco to New York in around 36 days, sailing our much-used veteran ocean greyhound, the Super Maxi 100. Time to try again, this time on the VO70. If you aim for a SOG of 18kn, it'll only take you a month.
Race #1567
INFO by brainaid.de
WX Updates:
0430 / 1030 / 1630 / 2230
Race starts: May 01st 19:00 Registration Closed

▶ Flash

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member WRmirekd
  2. Sailonline Yacht Club Member Vida_Maldita
  3. Sailonline Yacht Club Member rafa
  4. Sailonline Yacht Club Member Pit8008
  5. Sailonline Yacht Club Member GREATSKUA
  6. Sailonline Yacht Club Member FreyjaUSA
  7. Sailonline Yacht Club Member Sax747
  8. Sailonline Yacht Club Member Kipper1258
  9. Sailonline Yacht Club Member rumskib
  10. Sailonline Yacht Club Member Satori

View full list


Mobile Client

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

The mobile client