Using your GPS in the open water swim


apace cofounder Aditya Kelkar shares tips on using GPS at the open water swim
How does one best track the swim at a triathlon? - This is a familiar question for many triathletes.
  • If you use a multi-sport GPS device with a specific swimming function (e.g. FR 920XT) AND you are swimming freestyle, you can use the device in the open water swim mode. The wrist on which you are wearing the device gets to come out of the water every time the arm moves over the surface of the water, this allows the multi sport device to catch the GPS signal and track the route point.
  • If you swim breast-stroke, you unfortunately don’t get that advantage as arms are submerged in the water at all times, which means the GPS device cannot catch a signal, and the distance will not be tracked.
  • If you do not have a GPS device with a specific swim mode, it means your device may not be safe to use in water. (Check device documentation for details)
So it may seem like breast-stroke swimmers and those without a swim mode GPS device are out of luck, when it comes to distance tracking. But that’s not entirely true, there is a nifty trick that can be used to get over this situation. Endurance athlete and blogger DC Rainmaker writes this fantastic piece on this problem.
DCR recommends placing the GPS device under the swim cap. The device stays safe as it never goes deeper than 1m and if the user keeps his/her head (which is holding the device) mostly above the water then the GPS can track the distance easily.
During the recent Goa triathlon, I tried this trick to good effect. I did not use the ziplock bag as DCR recommends, but that was because my Forerunner 910XT has a swim mode, so it is safe to use in water. The following photos indicate how I used the device under my swim cap. By placing it so, I always knew where the buttons were if I needed to use them. The trick worked well. My swim at the Goa triathlon got tracked correctly, and showed that I swam 200m extra. This seemed to match with many of the other participants, so there was not too much error in measurement.
 
 
 Few things to consider:
  • Make sure you read your product manual carefully
  • Make sure the device is firmly under your swim cap
  • Make sure the swim cap is not torn, and will not tear due to the device
  • It is possible that a kick from another participant may dislodge your swim cap in the starting frenzy. So be careful during the start.
  • Use the device in smart recording mode
- Aditya Kelkar www.keepapace.com #keepapace

1 comment


  • Harper Campbell

    It’s interesting to learn that when it comes to using a GPS in swimming that there are some things that need to be considered to help make sure that things are done right. I am glad that you mentioned that when it comes to using one that I need to make sure that the one I use is safe to go into the water so that the mode will work properly. This will be great for the next time we go out on the lake and are wanting to navigate around it. http://www.sunvalleystereo.com


Leave a comment