Problem is - if termites are entering the boat through the shaft log there is something mighty wrong at the other end of the shaft log.
At the outside end is the cutlass bearing, the retaining plate and the propeller
shaft, etc. However, on the other end - inside the boat - is a stuffing box. Water, termites, whatever can enter the grooves (rifling) in the cutlass bearing but they should not be able to get past the stuffing box or a dripless bearing that is installed on the inside end of the shaft log.
So patching the "hole" on the outside is not going to do much as somehow the termites have worked their way through the stuffing box and water will do the same thing once the boat is back in the water. In other words, it will sink - slowly, but sink. Unless you seal the inside end of the shaft log/stuffing box/?
An option is to seal up both ends with liberal amounts of T5200 around the prop shaft and plate and the area around. Then do the same thing inside the boat by finding out how the termites are exiting the shaft log on the inside end. Then seal that up with T5200. - - Then tow the boat to its new home and get it out of the water.
Unless you got the boat "for nothing" I would hazard that the insides are trashed by the termites eating away all the bulkheads, mast keel
steps, floor beams, cabinets, and anything else made of wood. I would not "pay" for such a boat and taking it "free" would still be highly "iffy" as the cost of gutting the boat back to its plastic hull
and removing all the interior
and then putting a new interior
is going to cost more than buying
a new version.