I've done this many times on my Penn Yan and in the water. Do it on the hard if its your first time. If you find it easy, then its your choise from there. I recommend you get a dental pic or the pic tool they sell for getting the stuffing out. Remember, one circle of packing at a time and stager the joints. Do not install in a continuous wrap. There are also inexpensive wrenches for the large nuts. You need 2 wrenches, one for the nut and one for the stationary assembly. If you don't hold the assembly with a wrench, you'll break the hose or worse. Do not use a plumbers wrench, it will round off the brass nut edges. Count how many rings you took out and make sure you have the right size packing befor you start. Yes, there are many diameters. Its also made in the standard wax or more expensive teflon. Make sure you only have it hand tight to start and let it run in awhile. Then tighten until you get the proper drip for cooling while running. If too tight, you will burn the packing and ruin the shaft. Feel the nut after running for temp. Here is a link for a goot step by step. One of the best things i did was replace the assembly with a dripless P.S.S. dripless packing years ago. No more water and works great.