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Saturday, 06 June 2020
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Gps how to

Howie Rowson cruising at 40+ on his production kit.



Most production speed/slalom boards are easily capable of 40knots plus and even on the windiest days aren't far behind the speed needles (maybe a knot, or two knots if the course is tight) which are far harder to sail and will reduce the number of runs you can make down the course. Quite often you'll do better to do twice as many runs on a more forgiving board and catch those lucky gusts.

Setting it up

Assuming the ideal conditions of very windy and a broad angle, you'll need quite a bit more downhaul and less outhaul than for regular blasting. You really do need the sail to 'open up' as much as possible -so use the bottom clew cringle, lots of tack strap tension (if you have one) and pre-set lots of twist into the sail. (Too much outhaul or not enough downhaul will over tighten the leach)

GPS Units

If you're buying a new unit, you really should go for the GT31 (~£100). Your other options are the GT11 and Garmin 201 which will do the job if you can pick one up cheap off ebay or a mate, but aren't as accepted at the top of the gps ladder. You'll also need to buy an Aquapac, the Pro sports 208 or 212.

*!!PIMP WARNING!!* Try for your gps needs *!!PIMP WARNING!!*



This website is the hub of all GPS speedsailing activity. You can find all the information you need to get started, post your results, join World and British rankings, get weather reports, chat on the forum and read event reports. You'll need to register and make a note of your username and password.

Setting up your GT31

This is very straightforward. Simply follow the instructions HERE
For any problems THIS may help.

Downloading your results

The simplest way is to record all your data onto an SD card inside the GT31, you can then simply read the card on your computer's card reader which will be an sbn file.
Alternatively you can download the data as an sbp file using the NAVILINK II utility which comes on a disc with the GT31.



This website allows you to download the appropriate gps results program. Initially for a free 30 day trial and then years subscription.
Gps results is the easiest way to analyse your runs and send them to
Simply open your sbn file, check out you results, set your 'username and password' to match those on gps-speedsurfing, then send your results (all using the 'FILE' menu at the top)

Combining two tracks (optional)

The new 'record' ranking for those that wish to enter requires that you use two GT31 devices simultaneously and combine the results.

Select the first SBN-file (File - Open - left click), then press Ctrl and select the second SBN-file. You will then be asked if the two files shall be combined (averaged) - answer yes and if both firmware versions match you will see the combined results (red circle) together with the speeds from unit1 (GPS1), unit2 (GPS2), and the difference (green circle) and the errors (black circle - only if you used SDOP firmware):

Adding a session to Gps-speedsurfing

This is the fun part and very simple! Log in using your username and password under 'My GPS', then fill in your details and 'My Profile', then go to 'My Sessions' and choose 'automatic add session'. Fill in the requested data, then press send and your session will be shown in latest sessions. After your data has been checked (and you may be asked to produce the original file) you'll be added to the rankings. Joy!


Check out the UKWA website for more info on Weymouth Speed Week, The British GPS ladder and 'Ultimate Speed Meetings'.


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