Shawn,
I just drilled out my cotter pin. I noticed that one end was cracked and it broke right off when I tried to remove it.
My shaft is bronze, but the cotter pin was probably brass (it was significantly softer than the bearing grade bronze shaft). After drilling 3/16" or so I noticed the gunk holding it in was mostly at the ends, so I drove it out the rest of the way with a small drift.
If you can't get the old prop off, somebody here would probably be willing to give it a good home
Good luck!