Stuffing Box packing with GFO gortex

We have been using the GFO gore-tex packing material for many years and we find this to be nearly drip-less when installed. What I wanted to share is the fact that two rings of GFO in an IP35 packing nut seems to be more than enough. I know the rule is to install three rings of packing material, but allow me to defend my position. We have run two rings of GFO packing for many years. Today, when we repacked the stuffing box, I photo graphed the fact that three rings of GFO are too much due to the fullness of the 1/4" GFO packing. We have a 1 1/4" propeller shaft and this uses 1/4" GFO packing material. When we install ring number one, we then run the packing nut all the way up onto the stern tube to seat the packing material. Then we remove the nut and insert a second ring with the seam 180 degrees from the first ring. Now we run the packing nut up onto the stern tube to seat ring number two. This time, I looked at the amount of threads left. The I laid a third ring of GFO onto this area to see te amount of threads left. I feel that there are too few of threads left to make this a safe install. So, I only installed two rings of GFO packing. This is what I have done for many years and it works just fine.

Notes:
1. We have repacked the stern tube in the water and it is not a problem. The amount of inflowing water is about that of a fat drinking straw. Your bilge pump can keep up with this. It may seem scary to take apart the packing nut while in the water, but we have done it multiple times with no problems.

2. We use a 30" crow bar and a hammer to tap on the packing nut to loosen it.

3. The packing nut is normal threads, righty tighty, lefty loosy.

4. Use PB Blaster lube to help break it loose.

5. It can take an hour of hammering and tapping to loosen up the nut, that is how long it took me this time.

6. Use dental tools or small picks to get the old rings out. Us a mirror to see into the packing nut. Find the seam, start there.


Here are some photos




This picture shows the amount of threads that the cap nut threads up onto the stuffing box.
The locking nut is at the point where the cap nut is fully seated.




This picture shows the GFO Ring #3 and if installed would only allow a few threads in the cap nut.
The stop nut is at the position where the cap nut stops when seated with two GFO rings installed
So, I only install two rings of GFO.
Yes, I know it will compress, but two rings have worked well for thousands of sea miles....





Hayden

Hayden,, We're looking to repack the stuffing box while EOS is hauled this week. Do you still recommend using only 2 rings or have you changed your technique to be able to get 3 rings in?

I can only get 2 rings of GTO into ours, if you can get 3 rings in go ahead. I am running with 2.
Hayden

Thanks Hayden. I ended up with the same result …. with 3 in I only had about 1/2" of threads engaged and had difficulty getting the locking nut to travel that far forward. I removed the third ring and went with two.
Pete

You are welcome, Pete. That's the same results I had and I was not comfortable with so few of threads into the cap nut.. it works just fine with 2 rings.
Hayden

www.deepblueyachtsupply.com/3bpbw100-buc...packing-box-wrenches A set of these wrenches from Buck Algonquin make life a lot easier. Can add a pipe if more leverage is needed. Does less damage to the nuts.