Took my new fish finder on it's maiden voyage yesterday. It's really cool but I had trouble navigating back to my waypoints. Every time I would try to go back to a waypoint I would get to 145 ft. away and the arrival alarm would sound and it would stop navigating. Is there some setting that I need to change or am I doing something wrong? Also, when navigating to a waypoint there is an arrow but it seems to be pointing toward the boat. What am I missing here?