The latest update: I tried to remove the rudder, it wasn't anxious to leave it's home of the past 23 years. I was unable to remove the tiller arm, but I was successful in breaking off the zerk on the rudder shaft housing. Any remnants of grease in there was completely dried out and powdery.
Any hints on how to remove the tiller arm? Judging by the looks of the grease I think the rudder needs to be disassembled, cleaned out, and re-lubed.
PS: Good to hear from you Steve!