Yes
Yes, you have to remove the skeg to remove the rudder ( assuming stock setup ). If PO already rebuilt the bottom cup, I'd just leave everything alone. The groaning is ( likely ) from pressure against the upper wooden block, and then when it turns little bits, it makes a noise. Because of the skeg, I don;t think there is really much wear or play at the through hull "bearing". It just spins there. Most of the force is at the 2 ends. ( just my thought, not an engineer )Open the emergency tiller cover and look at the block. Is it a circle, or getting more like an oval. Is it worn in any areas ( looks burnt ). Is it greased? Does the shaft wobble or is it solid?Also watch while underway, looking for the wobble and listening for the sound.If any of these point to this being the culprit, I'd just get some waterproof grease in there and hope that does the trick.If the block hole is worn, but everything else seems good, I would try to cut a larger diameter hole ( still not pulling the rudder ), then install some type of flanged bearing down from the top. Doesn't have to be ball-bearings, could just be a derlin sleeve or someting that has a flange to screw into the top of the block. Saves pulling the rudder, fixes block problem. I saw some online for sale at about $ 100.00All this is 20-20 hindsight for me. But I would not pull the rudder for that groaning, too much work and room for error.Good luck.John