Stuffing Box Lessons

I did a lot of searching on this site and a lot of reading on the web before going to work on the stuffing boxes on my Californian 42 LRC. The boat had been sitting in a slip for at least 12 years. Not surprisingly, after a brief sea trial, the stuffing boxes were leaking more than they should. The jam nut and the packing nut were stuck fast and covered with a bluish green patina.

Following are some of the points I learned from the collective knowledge.

• I used two wrenches, a 18" pipe wrench and a plumbers slip wrench. The slip wrench looks similar to an adjustable wrench but the jaws are square and the wrench is short. These wrenches work but they are very clumsy to use.
• I have ordered 2 short spanner wrenches from ebay to keep in the boat tool box. My boat has 1 3/8" shafts and the 2 nuts are 2 1/2" and 2 3/8". I spent $35 for the dedicated wrenches and I consider it money well spent.
• If you use an adjustable slip wrench make sure to pull against the fixed jaw or the wrench will slip or break.
• If there is patina to clean off of the nuts and threads forget the PB Blaster or other penetrants, this is not the place for them. Use a mild acid and a brass brush. You will be surprised how fast the gunk loosens. I used bathroom tub and tile cleaner, but I think vinegar or lemon juice would work as well.
• If the jam nut is still stuck nothing beats a drift and hammer to loosen it. The shock load easily breaks it loose without stressing the tube/hose.
• After freeing up the nuts, I used the method of letting the boat pull against the dock lines in reverse at about 1000rpm. The packing nut was adjusted for 1 drop every minute.
• Don't take the wrench off of the packing nut until the jam nut is tightened against it, so the spinning shaft cannot spin the nut off and keep your hands and clothing off of the shaft.

I obtained satisfactory results and the boat is now ready to change marinas, but I will be replacing the packing in the near future because I want to know what I have down there . I hope this helps others.

Good for you. Self sufficiency makes for happy boating in my opinion. I too have dedicated (home made) wrenches. I painted them with hammerite and they are stored very close to the stuffing box. Of course I've never had to use them since I repacked with GFO, which I recommend highly. I've used GFO packing in dozens (hundreds?) of pumps and refiners. Although you can use almost any type of yarn packing if you pre lube it and break it in properly as it really isn't that tough of a dynamic seal to make.

I still keep my stuffing box on my hourly underway rounds. More out of habit than anything else, I suppose.

db2 said:

I did a lot of searching on this site and a lot of reading on the web before going to work on the stuffing boxes on my Californian 42 LRC.

Click to expand...

Don't you love the starboard stuffing box underneath the bathtub floor? Makes me want to scream!!

By the way, I switched to one of the Teflon graphite packing materials with good success, runs nice and cool. I have 1 3/8" shafts, 5/16 packing.

If you have trouble getting the packing in and out of the nut, you can wrap a rag around the shaft and stuff it into the open shaft log to stop the water flow. Then slide the packing nut all the way forward into the engine room. Much easier to work on when you're not laying on your side working through at 12" square hole.

Best of luck
Larry B.

why no PB blaster? Applied with a q tip, then wipe off with a rag i find it very helpfull. Just have to be super careful to never get it on rubber seals.

Working on a spinning shaft in incredibly dangerous. A moment's inattention and you could be maimed or killed, all for a drip of water and a bit of laziness?

Self-sufficiency perhaps, but getting killed for your hobby? Don't work on a spinning shaft!

I guess if you feel that strongly about it you shouldn't.

I recognize that there are different comfort levels associated with unfamiliar tasks and one should certainly address the risks and the consequences of the task; particularly if there is a coupling nearby.

But. It is common trade practice to set the leak rate of pump packing and such while the shaft is turning as it is a dynamic seal.

To put it in perspective, I would venture that it is far less dangerous than using a wood lathe.

DB2... Did a few little format modifications just to make it a touch easier to read. I hope you don't mind.

Here is a good write-up by MainSail about traditional stuffing boxes... May be worth a look:

Re-Packing A Traditional Stuffing Box Photo Gallery by Compass Marine at pbase.com