If you are running two units sharing WP it makes it a lot more accurate if you put both of your GPS pucks on the front of the boat. Other wise if my console unit puck is at the back of the boat and I mark something and them I go to the bow, the waypoint will be 20 foot off. I have a 20ft cast ring set on my front unit that also helps me know how close I am to a brush pile before I get on top of it.