Length depends on what kind of trolling you do.....if you pull crankbaits on big water and there is a good chop on it you will need one longer .... when your at the back of the boat reeling in and taking fish off ... if short shat the front of your boat is pitching up and down....your trolling motor will cavitate and will be hard to maintain even constant speed. With the 60 inch you just let it on down and troll on no problem.