Replacing blades the expensive way
FWIW, we had to replace the entire gearbox after sucking a mooring line weight through it (at least I think that's what the other owner did). All the blades were gone and one side of the shaft was cracked.
Notwithstanding the parts list, individual shaft/gear wasn't available and we had to replace the entire gearbox.
Needless to say we had to haul the boat and spend over a boat unit.
Interestingly, the new gear head doesn't use an oil reservoir, and seems to be fine after a couple of years use.
Mainia, '02 Mainship 390