I have recently replaced the rudder on our Wing Keel, 1999, Catalina 36. The rudder is 46 inches, which is slightly less deep than the wing keel. The rudder was fabricated by Foss Foam.

I have heard that the same length rudder was used on both the fin keel and the wing keel models.  So on the wing keel models the rudder is more susceptible to getting damaged.  Do not know if this was always the case but it seems like a bad design choice.

The wing keel rudder is shorter than the fin keel rudder.  If your rudder is deeper than your wing keel then someone had previously replaced the original rudder with the wrong one.  I recommend contacting Foss Foam in Florida, they can make either rudder for you and they are less expensive than Catalina Direct.

I've seen a lot of rudders on shallow draft keel boats (at our self-help club I work the haul out and launch crew every year) and most (all?) have shorter rudders than the depth of the keel for obvious reasons (I. E. Your issue). The difference is that they match the volume of surface area of a deep narrow rudder with a shorter but much longer rudder. To control the steerage it is all about the amount of surface area that is in contact with the water behind the keel.