Jag hittade detta på Garmin hemsida om det hjälper:
The Forerunner 310XT times your swim in the pool or the lake. And while the GPS signal does not track distance while swimming like it does on land, thanks to a recent software update, it now accurately estimates open water swim distance and average speed. Simply enable the Swim mode and press start as you begin your swim. When finished, press the lap button and the 310XT automatically processes a combination of the time and GPS data to compute an estimate of distance covered and average speed while swimming.
det finns en länk där, där det står "software update"
https://buy.garmin.com/shop/shop.do?cID=142&pID=27335
