If you are paddling up a river with alot of switchbacks I suggest you drop your tracking from 10 minutes to every 5. I don't typically paddle way up my local rivers where it is narrow. I like the ICW and the local bays and mangrove islands. My GPS says I did 20.3 miles but the Spot tracker only says 16. I started hitting an OK message at every big turn. The WaterTribe tracker seems to be down right now but you can go to the Tracking page and then click on the Race Owl link that is still active and look for "WaterScout" to see what it looked like.
Luckily you can still use the time calculation for points if you run into this problem. Posted this to facebook as well.