Seawind 31 rudder design

have just found this site. I have a Seawind 31 launched in 1988 in Gosford. Original name was Brandy. When I purchased her her name was Oyster Catcher. I have rechristended her Tora Tora (Tiger Tiger in Japanese). She lies on a swing mooring in Moreton Bay @ Victoria Point, Brisbane. The boat was extended at the stern by approx 1 meter. Somewhere in her life heavy tiller (weather helm) must have bothered an owner and the rudders were modified. From a straight rectangular shape a forward protrusion was added making the rudder look like a Christmas stocking. Consequently it became impossible to lift the rudders out of the water via their box since the "boot" protruded under the hull. Weather helm remained a problem. I have recently cut off the "boots" and am lengthening the rudders to make them about 10 inches deeper. The boots had a surface are of about 140 square inches. My extension will be about 180 square inches. I would love input from anyone who knows the boat, is familiar with Seawind 31's, knows more about rudders than I do (not much) etc. Slava :?: