Basic rules

Basic Rules
Version 9.1 A2 - 12-12-2016

1. GPS Track

The verification of tracks is the basis of the site! Therefore a GPS track needs to be available for verification by a (Regional) Time Keeper (RTK) at all times. We only allow full & authentic name registrations.

Even after a year or more the RTK’s could still ask to send the track, so always make backups of the files. Always save the original tracklog file and when you have deleted spikes (when applicable in non-doppler devices) save this file with a different name (add cleaned to the file name).

Never change the new of the original SBN, SBP or .UBX files . If necessary make a copy of that file.

A rider can also send the track to a special e-mail address: info(at)gps-speedsurfing(dot)com. Please also mark the box in the session screen when you have send the track.

When a RTK does a request for a track, it will need to be sent within 5 days to the RTK.

If a rider does not comply to this rule the session will be set to inactive. It is also possible to  set the rider profile to inactive when a rider does not cooperate at all or there have been multiple problems with following any of the rules.

From mid 2011 it will be possible to calculate the statistics via the site and the track is saved at the GP3S server and made available to Premium-members. Just make sure that you always keep/backup a copy yourself just in case.

2. GPS Device List

Not every GPS is suited for use with any of the other sites).

Please check the most actual device list under this section:

3. GPS used

In the riders ‘My Profile’ it is necessary to select the type of GPS mainly used. In the session it is also necessary to select the GPS which is used for the session (when different from the one in the profile).

4. Doppler postings

Everyone posting with a Doppler device has to post speeds in Doppler.

Once a session is posted with a Doppler device it is not allowed to post a session with a non-doppler device anymore.

5. Track format
A track must be delivered at the discretion of the RTK in the next name format (for Garmin tracks): YYYYMMDD Rider Location.gpx or the Navi generated filename (without changes) is also ok. Make sure you have your Username set correctly in the Navi.

When you have deleted spikes in a copy of the original Garmin GPX file than add ‘cleaned’ to the file name. (example: 061205 John Doe The Spot Cleaned.gpx).

It is requested to not clear the Datalogger in your Navi as this functions as a backup. It can also be asked by a RTK to send the full SBP file of your GPS for verification purposes. If you cannot do that, your posted session could be deleted.

Only tracks in GPX, SBN/SBP or .UBX format with minimum of 6 digits precision are allowed.

6. Software allowed
Because it is possible to calculate the statistics and post a session directly via the site (with a SBN file) it is not 100% necessary to use any extra software. The engine is used at the site is GPS Results.

For analysis of a track and also posting the calculated statistics of a session the following software is allowed:

  1. GPS Action Replay
  2. GPS Results

The software developers will update the software regularly so check their sites or watch the announcements on fornew releases.

Any sessions posted with results NOT calculated via these tools can be invalidated if it is not possible to easily check the results via the allowed software. If it is possible to change the format of the trackfiles used and the differences are very small (to the judgement of the RTK) then a session could be allowed.

7. GPS Track Setup:

Doppler settings:

When a Doppler device is used, it is obligatory to use it in that mode when calculating your statistics.

Not allowed settings:

  1. Distance: This setting is not allowed, because it can give too much variation in the track and we want to have one single setting so there can be no discussion about the speeds.
  2. AUTO: Never use the AUTO function or save a track in your GPS. This way you will loose valuable track data.
  3. WAAS: Also do not use the WAAS function. In some areas of the world this has caused problems with the tracks.

Any posted session that is based on a track that has been at AUTO setting, has too much variation and/or spikes can be discarded by a RTK. If you are not sure about a track then first contact your RTK before posting a session.

8. Run

A run is when you sail in one direction and per run you can score only one speed. A new run begins after a turn (gybe or tack) or when you have stopped. The only exceptions are the Nautical Mile, Alpha, Distance (24h) and one Hour speeds where turns are allowed.

A valid run has no spikes and no strange accelerations or decelerations. If a spike occurs at the end of a run (because of a crash) the spike may be deleted and the run can count as a valid run. When there are strange decelerations a run can also be discarded.

For Doppler devices in the GPS analysis software the following settings are necessary:

  1. max. Accel. [5 m/s²]
  2. max. HDoP (5)
  3. min. Sats (5)

9. Rankings
The main ranking for is the Average over 5 runs of 10 seconds.

Although we look at the statistics for the other rankings seriously, they have been added for more fun rankings and can only be interpreted and used as such.

The Year and Month rankings on the homepage are only for Doppler sessions and when posting via the Auto option in your analysis software or via the Automatic posting via the site. When you cannot post with an Automatic function then you can contact the Timekeeper with an explanation and he can make your session visible in the rankings if you have a valid reason.

Other rankings can be made Doppler rankings at the choice of the webmasters.

Verifying of speeds for the rankings is done on a best effort basis. Sometimes it may take a while because of available time and contacted other experts for advice.

10. Session data
When calculating the session statistics it is important to comply to the following rules:

  1. One best per run
  2. Linear Speed. (Linear speed means that you calculate the speed over the exact positions a rider has sailed)
  3. No interpolation of distance speeds
  4. Use the Doppler function when applicable
  5. Set Cubic Spline integration

A session consists of:

  1. Max Software (2 sec) - Software calculated highest speed
  2. 10 sec run - Software calculated average speed over 10 seconds

(the AVG for the ranking is calculated over the 5x 10 sec runs)

  1. 100m - Software calculated average speed over ‘one’ run of minimal 100 meters
  2. 250m - Software calculated average speed over ‘one’ run of minimal 250 meters
  3. 500m - Software calculated average speed over ‘one’ run of minimal 500 meters
  4. 1852m - Software calculated average speed over ‘one’ run of minimal 1852 meters (Nautical Mile), turn allowed*
  5. Alpha racing – Software calculated speed over ‘one’ run of 500 meters with a gybe and a proximity at the startpoint of 50 meters.
  6. 3600s (1 hour) - Software calculated average speed over 3600 seconds
  7. 24 hours – average speed:
    • No minimum speed
    • Slogging and short walking is allowed
    • The best 24h period out of the session is selected. It can therefore be sailed over a two day period.
  8. Distance - Distance sailed during a session (minimum speed is 5 knots)


Please send the data via the automatic upload function in the software or via the upload functionality from the site. This prevents making mistakes and helps the checking process. Also only sessions posted via the auto function (and Doppler) will be visible in the front page rankings (when in the top 10).


When you post a -normal- session you select the spot, board, sail etc. combo with which you think you have reached the highest max or the best average. So it is allowed to use different boards, sails, etc. on one day.

Besides the NM and hour speeds, all other measurements must be filled in when posting a session. If one or more speeds have not been filled in, the session can be discarded.

Please also add some remarks or a story of the day. This is very nice to read for the other members of the site.

11. Multiple sessions

Multiple sessions per day are allowed

  1. when they are on different locations and this can be clearly seen on the track
  2. for multiple boards when they have been sailed after each other and it can be seen from the track or there are witnesses


A single session for a day is not allowed when the runs are sailed at two different locations.

This must be clear from the starting point of the different sessions. When a rider sails from one location to the other the rider has to choose the location is started from.

12. Posting a session within 7 days
When posting a session this must be within 7 days when the session has been sailed. When you are not able to do that you can post the session but it is set to invalid. Please contact  your RTK via e-mail with an explanation (f.i. holiday) so it can be validated. When there is no good argument, the session may be deleted from the database.

13. Location
Always fill in the correct location where you have been speedsurfing. It is allowed to give a new spot a name when it is not yet marked at a map or known in the region. Secret spots are not allowed.

14. Speed material used
Only windsurfers are allowed to post on the site. Kitesurfers can post their speeds on Other windpowered crafts like landsailers -/surfers or iceboarders are not allowed. Other websites will be developed for these groups, f.i.

15. Once posted sessions

It is possible to delete a session when f.i. there have been two sessions posted by accident.

It is not allowed to repost a once posted session to change the speeds. This is only possible after contact with a RTK when it is clear that there has been a mistake. Reposting because of small changes due to new software/calculations are not allowed.

It is however possible to change the non-speed fields in a session like board, spot etc.