This device is meant for people who swim in seas and oceans and do not have the advantage of knowing how far they’ve swum because there are no lane markers or clearly-defined lap lengths.
Priced at $130 (£87), you can purchase the hydro tracker from the Finis website. The waterproof device is simple to use and requires no calibration. It is attached to goggle straps and usually, it is positioned on the back of the swimmer’s head. It may be a good idea to move it to the side if you decide to swim on your back.
The hydro tracker is powered by a rechargeable Lithium ion battery pack. On a full charge, it is reported to give you up to 16 hours of service.
As the device works on GPS technology, the higher the frequency with which positional data is received from the satellite, greater the rate at which the battery will discharge. To maximise battery life per charge, adjust the sampling rate.
Although the hydro tracker was primarily designed for use in water, it will serve the same purpose if you’re on a run or a hike. Just wear it on an armband and its GPS gets busy capturing information on how far you’ve walked, what elevation you’ve reached and so on.
Once you’ve finished your swim or hike, download the data from the hydro tracker to your computer or tablet. You can then use the data to monitor your performance. With lots of training (and some luck), you will see your performance on a steady upward graph.