I have just purchased a 2001 Hunter 240. I am having trouble getting the rudder to fully deploy. I need to actually step on it while I pull the downhaul line. Once it is completely down, as I sail it begins to creep up, so that after a short time steering becomes tough. Is this just the way this rudder operates? Does anyone have any suggestions? Am I perhaps missing a part on the downhaul apparatus? Any input would be greatly appreciated.