I would strongly recommend against using plumbers putty or any other paste product in your stuffing box. I've changed out packing many times while the boat was in the water but done it more often on a tidal grid which is easy to use. I've worked on smaller sailboats down to 1" shafts and larger seineboats up to 4 " shafts and many in between and the process is much the same. In on a high tide and button your vessel up close to one side, well fendered (I used to hang an old blanket between the fenders and the boat to protect the gel coat or paint). If there is not planking on the side of the tide grid you are tying to, put a 15-20 foot 2X6 or 2X8 between the fenders and the tide grid dolphins
. Don't try and match up your fenders with each dolphin.
As your vessel settles on the base of the grid, adjust your ties to keep your boat upright. Tie off the other side of your vessel snugly once she has settled if there dolphins
on the other side to maintain an upright position.
Undo your stuffing box retaining nut completely and slide it up the shaft away from where you are going to be removing the old packing. Either purchase
a packing removal
tool or make one out of an old ice pick with the sharp end bent over past 90 degrees and begin hoeing out the old packing. Be absolutely certain you get all the old packing out. You will have to heat the end of the ice pick to bend it otherwise it will break off.
Take the shaft measurement and opening measurement between the shaft and the inside of the stuffing box. Marine
stores have a variety of shaft packing in specific diameters... be sure to get the correct size. Be sure you get flaxed packing for longer wear, ease of insertion and correct weepage. You need a small bit of weepage to lubricate the shaft inside your gland assembly. No drip=burnt shaft.
Cut the length of packing strips end on the bias to fit the shaft and stuff it in with your packing tool ensuring that your bias cuts match up around the shaft inside the stuffing box. You need at least three rings of packing, each one staggered, so they don't terminate at the same spot on the shaft. Poke them all in tightly.
Slide your tightening nut down the shaft and make it fast 1/4 turn past hand tight. The knurl on the end of the tightening nut must contact the packing... if not, another round of packing is needed.
Open a beer
and wait for the tide to come back in. If you haven't checked your zincs for a while and you still have access beneath you boat, now is a good time to replace them as well.
Open another beer
and when the tide rises sufficiently to cover the shaft, inspect your stuffing box and adjust tightness to allow 2-4 drips a minute. That will provide perfect lubrication. After you have run the engine
for about 1/2 hour, check again then run her for 3-4 hours and check again. you will probably have to fine tune the tightness at least once once after running in.
Don't loosen your tie-up until you feel the boat floating freely.
If you choose to repack in the water, you will take on some water and may find it difficult to place the new packing in the gland but it is certainly doable.
Hope this helps... it is an easy process and there are pictures step by step available on the web to walk you through. This is a simple maintenance
procedure and one that every boat owner/user should know and be able to handle in the dark! Cheeers, Phil