Agree with Oceanrider007 that not enough info is provided. Low speed, not enough rudder authority is a common issue that one typically finds a way around -- like keeping your speed up. Also--problems in reverse happen simply because of prop walk and technique (or lack of it) in terms of backing with a full keel boat. OTOH, you can have problems with cables
, steering gear
, quadrant, etc, which are entirely different. More info?
PS --when we rebuilt our boat, we discovered a previous owner had wacked off about 4" of rudder. We rebuilt it to the full rudder size (all the removed material was aft) and it works wonderfully. We suspect the material was removed because the old rudder had rotted or been damaged at some point. Works wonderfully as designed by the naval architect. Do you have your original NA plans?