Sounds like you have the std, old fashion, stuffing box, with 3 or 4 rings of square flax/tallow packing material. If you haven't even adjusted it in 12 years, how could you ever beat that for service?? My advice, tighten it slightly (until one drip per minute) using a hammer and punch if wrenches won't fit in your keel; for the rest of the season. Repack it per easly found instructions when you haul, and don't bother with the new dripless stuffing boxes. They have problems of their own.
PS: If you decide to remove it and the shaft when you are hauled, replace the 12 year old hose and champs with the best & proper stuff and if your wrench space is real tight, grind some notches in the nut & locknut for your punch & hammer method.