Hi Bob,
My JD paddle shaft is 3/16" dia straight through and it runs in ball races in their own housings on the inside of the hull.#
The ball races are fitted into a 1/4" bakelite which has been counter bored to take half of them, and a cap over the other half width, with a grease pipe to each bearing using a screw down grease cup. The bakelite is then bonded onto the hull.
There is more shaft clearance to the outside of the hull, than the inside so that when I screw down the cups, more grease goes out the boat, than in, so I don’t have any water problems.
AT