SailNet Community banner
1 - 17 of 17 Posts

·
Registered
Joined
·
139 Posts
Discussion Starter · #1 ·
Recently discovered my rudder stuffing box had 4 layers (or rings) of packing, while my propeller shaft box had only 2. Both were leaking more than they should have been, I'm replacing the packing now. Wondering if I should stick with the # of layers that were in there (4 & 2) or try to get them both to work with what seems to be the standard 3 layers?
 

·
Registered
Joined
·
1,942 Posts
for the shaft its simple as many will fit and allow a few turns of the nut. then adjust to the desired drip rate.

for the rudder i dont know
 

·
Telstar 28
Joined
·
993 Posts
Basically, put what will fit in them. :)
 

·
Registered
Joined
·
967 Posts
2 is too few, and 6 is probably too many

I don't 3 is the norm either. My SB holds 4, I maybe able to get 5 in of the newer GTU Packing as it doesn't swell as much as the older flax packing, but when I removed the old flax, I pulled out four so I replaced with 4. SD is right, put as many "rings" as will fit. Try this technique:

Remove all the old stuff first, and then pack the first two rings of the new stuff in and snug firmly down, Loosen packing nut and put a third ring in and tighten again pretty snug. Continue adding rings and tightening until you can't get the packing nut to get a full turn on the SB threads before tightening. Once you get the max material in, tighten until the drip rate is at the level that you want while the shaft is stationary and spinning.

The general rule of thumb for the SB is while the shaft is not spinning, you should not see any drips for at least a few minutes, preferably none at all, and while the shaft is spinning a 2 to 5 drips/minute. The main thing to remember is that the drip rate is not the sole measurement, adjust the packing nut so that while the shaft is spinning, the drip rate is results in no heat build-up in the shaft.

For the Rudder post, you should adjust just snug enough so that there is no evidence of drips even even when turn the shaft. Do not over tighten or you can bind the shaft.

DrB
 

·
Registered
Joined
·
139 Posts
Discussion Starter · #6 ·
I maybe able to get 5 in of the newer GTU Packing as it doesn't swell as much as the older flax packing
DrB
So the packing swells eh ... I'm asking because I got the new fancy GTU packing here in 2 sizes, 1/4" and 5/16". The old packing appears to be in-between these sizes. So I should go for the smaller-appearing 1/4" I suppose and it will swell to fit?
 

·
Registered
Joined
·
140 Posts
First time repacking new-to-use boat. The boat is out of the water and the shaft is disconnected from the transmission, so I can experiment on the workbench.

My problem is that I don't know what size packing to use. The old packing consisted of 4 rings (hard and densely packed, thicker vertically perpendicular to the shaft axis than along the shaft axis). Measurements tell me that 1/4" should fit, but 1/4" teflon impregnated packing is a bit hard to fit in. I can get it in, but can only fit 3 rings, and then have about 3-4 threads on the packing box when I screw it down not too firmly. Shaft is 7/8".

1. Will that packing swell, or compress more over time?
2. Should I drop down to 3/16" packing, if I can get it?
 

·
Registered
Joined
·
4,304 Posts
While you can deform any packing to fit if you squish it enough it does not really swell :)

I have seen plenty of people bang it flat with a hammer to get a "GOOD" :) fit when they had to small of a size

So it should be pretty snug fitting it but not require a BFH :)
 

·
Telstar 28
Joined
·
993 Posts
Why would they have to bang it with a hammer if it was too small a size???

While you can deform any packing to fit if you squish it enough it does not really swell :)

I have seen plenty of people bang it flat with a hammer to get a "GOOD" :) fit when they had to small of a size

So it should be pretty snug fitting it but not require a BFH :)
 

·
Registered
Joined
·
695 Posts
3 rings of 1/4" should be fine. Believe it or not my packing gland only has room for 1 ring of 1/4". I did cut one ring lenghtwise and so I have 1 and 1/2 rings in there but it works fine so 3 rings should be plenty.

Gary
 

·
Registered
Joined
·
4,304 Posts
If you need 1/4 and you have 3/16 its a big gap as far as fluids go :)


With all the things you have seen people do you thing soembody will not try and turn 3/16 into 1/4 OR wack 5/16 to flatten it to fit into a 1/4 space :)


Its not like packing is only use in boats
 

·
A New Adventurer
Joined
·
283 Posts
Old thread, but it seemed more appropriate to revive this than start a new one.

How many threads would the minimum be for a female nut on the stuffing box? I used the Gore 1/4" from EMarine, but after measuring it, it seems to be slightly larger than 1/4". I could make it fit in the nut, but with 3 rings installed (what I had in there before) I could only spin the nut on maybe two to three threads. This seems like way to little.

It appeared that I had the Gore rings seated properly one at a time, but I could remove each one and try again. The only fear is that they shred pretty easily and I don't want to ruin them by removing them. I only have enough for one more new ring.
 

·
Registered
Joined
·
666 Posts
Hard to say but it sound like enough. Did you grease them well with teflon grease? That has really worked well for me. I would then tighten the nut good and snug and then back it off a bit. Final adjustment was with the engine running.

Gene
 

·
Somewhat Flexible Member
Joined
·
3,425 Posts
having years of experience with power boats, i've found packing as many rounds as possible and still being able to get at least four or five threads before having to apply a lot of force tightening (compressing the packing) the stuffing box is a good rule of thumb. not enough threads can cause gland nut failure, while too many will not allow proper compression of the packing. i always put water pump grease on the packing beforehand for ease (albeit messy) of installation. good luck........

scott
 

·
Registered
Joined
·
847 Posts
When installing the packing make sure to rotate each layer so the cuts are not on top of each other. For example with 3 layers move the cut 120 degrees in each successive layer.
 

·
A New Adventurer
Joined
·
283 Posts
Like everything (it seems) in boating, there are many different opinions concerning proper way of doing things. Greasing these bad boys during install is one of those items. If I remember correctly, Saildog and Mainsail both said not to grease them before hand, but others say to grease them. I don't think they seated properly without greasing them the first time. I guess I'll give it a try and report back.
 

·
Registered
Joined
·
666 Posts
You are correct, lots of ways of doing it. And - all will work. Some of us have found a method that seems to work better and lasts longer. I have had 3 sailboats and 2 power boats. One of the power boats had twin screw powered by 350 V8's which puts an extreme amount of wear and stress on packing glands. I found if I used Teflon impregnated packing with Teflon grease, offsetting individual wraps, compressing and backing off and then adjusting under power then it was the last maintenance I would really need. The packing never needed to be replaced again, at least as far as I know. Only minor adjustments needed to be made the first few weeks or months of use then I could just check it occasionally.

But you can do it many ways and the worst that can happen is you will need to adjust it more often and change it every few years. No big deal either way. The only major concerns are that the shaft stays cool enough and that it doesn't sink your boat.

Gene
 
1 - 17 of 17 Posts
Top