Memorialize your whole trip at once
One of the new additions to the Navionics app is the ability to capture your entire trip in one single shot. Once you start a track with the app, any pictures you take along the way will be added to that track and saved in one place. So, besides having your entire track with distance, average speed and a map of where you've been, you'll also have pictures from that day. Here is a one from a bass-fishing kayak trip last week, which explains the lack of speed. On my phone, I can click on the top box and it will show me the entire track.