I had Martec refurbish my prop last summer and in made a big difference. The prop nut is a right hand thread. Make sure you have the the cotter pins completely removed. I ended up using a pair of vice grip pliers and a rag on the propshaft and then loosening the prop nut. I agree about the hub being loose and poor performance. I don't know who installed the prop the last time but it was loose on the shaft even though the nut was tight. It turned out the threads had a deposit on them that kept the nut from being properly tightened. Chasing them with a 1/2 - 13 tap fixed the problem. The Martec link in the above post has a good description on how to remove and install the prop.
