A silly question, but what shape is your rudder in? Any chance the rudder post got bent in a grounding? I ask because I once owned a Hunter 27 and it had terrible weather helm, the tiller was cracking from the load. When it was hauled for the winter I took a look at the rudder, and I thought it looked bent backwards. I looked at several others in the marina, and some looked worse than mine! So igot dimensions from Hunter for verification. Mine was bent back, about four inches at the tip. I measured another boat at 11" of bend! So I pulled the rudder and straightened it. Quite a job hanging it from slings in a hydraulic press. Afterwards I could sali for upwards of half an hour without touching the tiller, just trimming the sails a touch here and there!
Gary H. Lucas