Forget It!
It is my observation that Hunter's rudders tend to be sized on the borderline. As long as the rudder does not extend below the (modified) keel I would think you'll be OK. These sage words of advice come to mind: "Avoid running aground."As an experiment I made up a temporary arrangement to extend the rudder on my H 33 aft 2 inches. (Don't ask how.) Control over weather helm is improved. Steering under power, response and feel are improved. Can't realy tell if there's a loss of performance, not sure I care. The extension will be made permanent over this coming winter.You might get away with shortening if you extend fore and aft. 80% / 20% to maintain balance.I have the August, 1998 Sail Magazine article on cutting the keel. I could scan and e-mail it to you if you like.samlust@monmouth.com