This is just a clip, not a full story, of boating on Lake Tahoe. The video is taken with my Dji Phantom 2 Vision. At the start of the video, you can see that we (in the boat) are just starting to move. Within a few seconds, the speed of the boat increases. We ultimately got up to just about 20 miles/hour. I had no trouble keeping the Phantom in front of the boat. At about 40 seconds in, I move the Phantom to the port side of the boat. I experimented with moving closer and further away, not having any trouble synchronizing the Phantom position with the boat. However, if you keep watching, at 1:33 seconds, you will see that the Phantom stops dead (fortunately, not in the water!) and the boat shoots out in front.
So what happened? The Phantom recorded it's start point, which was, by this time quite a distance behind us. So the Phantom reached it's programed limit distance away from the start point and stopped!
Keep this in mind if you are flying your Phantom from a boat.