A hydraulic puller is another option for the really stubborn ones, but still works better if you load it up and give the end a smack. Protect against the prop/puller assembly flying off by keeping the nut on the shaft.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)