Packing Flax

I'm replacing the packing on my rudder shaft and my drive shaft. How many rings of packing flax rope should I use? I removed 5 rings from the rudder shaft and 3 rings from the drive shaft, but I thought I would want more than 3 on the drive shaft.

Also, how do I determine the initial torque on the packing nut (before I put it back in the water)?

In my younger days, I ran commercial fishing vessels and had the opportunity to repack the stuffing boxes on several larger boats. I would imagine that the theory remains true for smaller boats as well. Physics is physics, isn't it???

We would install the packing material and then tighten the gland until we could not turn the wheel. This was done gradually so that we could determine exactly when we met the point where the wheel could not be rotated. Need to be careful with this as compressing the packing too much and running the engine will probably glaze the packing and you are back where you started.

After re-floating the vessel we would run for an hour or so and check out the leakage. Oh yeah, there was always someone stationed to keep an eye on the stuffing box during the 'break-in". This proceedure usually worked without a hitch (or further adjustment) unless the shaft was not perfectly true.

Then again, these shafts were 4 - 6 inches in diameter, powered by 1,000 hp and turning 72 - 84 inch wheels at 300 - 350 RPM. Like I said earlier, the theory should be the same, just a different scale.

you cut the flax 2 pi r ....3.14 inch pieces and stager the gap like piston rings.

my 78 has 3 for the prop shaft and 4 for the rudder shaft, I don't know if thats the way it came from correct craft or not.?.?.?

if the gland nut is barely on, pull a couple out and see if the gland nut bottoms out. if it does add one. you want good engagement of the threads, but you want to leave some room to tighten it up after the packing burnishes in.

let the water soak the packing before you put the boat in gear. you should have plenty of time to be a ramp hog.