Kevin; I have the same boat as yours; the shaft packing is 1/4 inch flax.  Wrap a lenght tightly around the shaft next to the coupling and cut it with a razor sheetrock knife. Cut yourself  3 or 4 pieces to fit around the shaft.  You will need a cork screw like device to pick out and extract ALL the OLD Packing.  A dentists pick also works well. Stager the flax string ends when you insert them into the packing gland around the shaft and then tighten down the packing nut to a point where the packing does not leak water into the boat when the engine is shut off but does allow a couple of drops per minute to drip in when the engine is running and the shaft is spinningfor lubrication.  However, If you try this with the boat in the water then you better have everything you need to do the job ready and at hand with bilge pumps in working order before you start this project because water is going to come pouring in as you take off the packing nut and pull out the old packing.  And the old packing is not going to want to come out and it is not going to come out in nice complete strips.  But it can be done with the boat in the water, just don't get frantic. Willie Leipert, VT.