Rudder bearings
On many Hunters of this era there is a rudder stuffing box that acts as the bearing surface for the rudder shaft. In older boats such as yours, the packing gland and/or rudder shaft often develop corrosion or holes. Sometimes this is a source of water in the bilge. Many older boats have had this part replaced. At a minimum, you want to check it and repack if necessary. This could also be the source of your drag. I would also check for a bent rudder shaft. Running aground can do this fairly easily. Rudder will probably have to be dropped if bent very much.
