I have a Classic 30 which has a rudder arrangement different to that on the 32. On my boat, slackening off the clamp which forms part of the tiler fitting will allow the rudder to fall out of the bottom of the boat, so you would be well advised to proceed with caution. The “plug” to which you refer is most likely to be the top bearing and the stiffness is likely to be located in the lower bearing where prolonged immersion in seawater sometimes causes swelling, depending on the material from which it is made. A solution to this problem starts with a lift-out, unless of course you are intending to effect a temporary solution by removing the top bearing and pouring in some kind of lubricant. In this case,as I said, proceed with caution.
Here is a link to a supplier to rudder parts for the Classic series, which may give some kind of clue as to what youare looking at:
https://www.international-boat-spares.com/en/55-classic-32-tiller-version
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