You may need to turn the rudder slightly to provide clearance. Remove the nut and screw the prop knocker, aka harmonic puller, onto the shaft. Hand-tighten, then rap — don't bang — on the prop knocker four or five times with a hammer. (Oh yeah, don't miss and hit the prop.) Hopefully, the vibration loosened the prop from the shaft taper. Grasp the prop, remove the knocker, and remove the prop. If several knocking attempts fail, move on to another method.