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Old 05-27-2018, 09:57 AM   #1
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Shaft packing size

Going to repack both shafts, never done it before. In the water. GB 42' w/ FL 135's and 1 1/2" stainless steel shaft. Packing gland, sorry no pics, is the type with two tightening nuts, one inboard, one out. Want to have the packing material on board when I do it but not sure of the size. From what I read a good guess would be 1/4" or 3/8". Anyone disagree with that estimate? West Marine is close but trying not to leave in the middle of the big event.

Don't want to start a packing material war but WM sells GTU Gore and PTFE packing material. Should I go with one over the other (he asks thereby starting the war). WIthout any comments I think I would choose PTFE as, if I remember correctly, GTU is graphite which can possibly cause corrosion issues? Any comments appreciated and a classic meme from RTF would just take the cake.
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Old 05-27-2018, 10:08 AM   #2
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Old 05-27-2018, 10:10 AM   #3
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Can't help you with size, but having strips of cloth to wrap around the shaft & jam against the flow of water, plus 1" by about 1' strips cut from a bicycle inner tube to tightly tie & hold the cloth in place does wonders for slowing the flow of water to a trickle.

It's much easier to concentrate when it doesn't sound like the ocean is trying to fill your boat
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Old 05-27-2018, 10:18 AM   #4
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...is the type with two tightening nuts, one inboard, one out.
Then again...just reread your post and am unsure of this type...
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Old 05-27-2018, 10:31 AM   #5
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We replaced the PTFE with Gore and it has worked as advertised. Here’s a comparison.

https://www.gallagherseals.com/blog/...eptfe-packing/

If you can undo the gland without sinking the boat, get a few drill bits and slide those between the collar and the shaft to determine the correct size of the packing. I think 3/8” is to big. Our 2” shaft uses 1/4”.
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Old 05-27-2018, 10:38 AM   #6
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Great tip on the rags and the old bicycle inner tub trick to slow the flow.

West Marine is pretty good about taking stuff back. If youre not sure, Id be inclined to get a couple of sizes and return the wrong one.

Also, if you have an old, long, thin flat head screwdriver, you might find some benefit from bending the tip around into a sort of flat head hook. Very handy for reaching up inside the gland nut to extract the old packing.
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Old 05-27-2018, 10:49 AM   #7
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Now THAT's a classic meme...so proud. Thanks guys. Here is an online pic that shows the type I have although much older of course. I'm not really concerned about the water coming in as it seems it would be easy to shove something in there and tighten up the bolts some to slow it down if something was amiss. Will also have someone else with me as well.
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Old 05-27-2018, 10:57 AM   #8
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It's much easier to concentrate when it doesn't sound like the ocean is trying to fill your boat
My wife says that's who she feel every time we go out. OK, it wasn't my wife, it was me.
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Old 05-27-2018, 11:05 AM   #9
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We replaced the PTFE with Gore and it has worked as advertised. Here’s a comparison.

https://www.gallagherseals.com/blog/...eptfe-packing/

If you can undo the gland without sinking the boat, get a few drill bits and slide those between the collar and the shaft to determine the correct size of the packing. I think 3/8” is to big. Our 2” shaft uses 1/4”.
Thanks Larry, good tip which I had forgotten. For the record, taking things back to WM is one of my best skills. I think 1/4" is the smallest they make. Probably wouldn't hurt to get up to 1/2" although no way is it that big. I think the calc for length needed is 14 times the shaft size so I need 20"-24" for each shaft if I can get 4 rings in there.
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Old 05-27-2018, 11:20 AM   #10
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Greetings,
I'm still of the thought that the two tightening nuts should be locked against each other on the outside of the flange. That allows the flange to remain snugged up against the packing yet still "float" allowing a very slight amount of movement IF necessary. Thoughts?


NOT like this:





But, like this:


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Old 05-27-2018, 02:39 PM   #11
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Quote:
Originally Posted by firstbase View Post
Now THAT's a classic meme...so proud. Thanks guys. Here is an online pic that shows the type I have although much older of course. I'm not really concerned about the water coming in as it seems it would be easy to shove something in there and tighten up the bolts some to slow it down if something was amiss. Will also have someone else with me as well.
I have an image of you trying to force it back together and water is just soaking you under high pressure while your reaching for the hammer. Do you have goggles?
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Old 05-27-2018, 03:13 PM   #12
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We have that type of stuffing box with water injection. My 2 shaft takes 3/8 packing.
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Old 05-27-2018, 03:16 PM   #13
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[QUOTE=RT Firefly;666674]Greetings,
I'm still of the thought that the two tightening nuts should be locked against each other on the outside of the flange. That allows the flange to remain snugged up against the packing yet still "float" allowing a very slight amount of movement IF necessary. Thoughts

My nuts are both on the forward side.
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Old 05-27-2018, 07:39 PM   #14
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My 1.75" shaft takes 3/4" packing. I found a marine store that took back the 1/4 and 3/8 that I bought at first and sold me the 1/2 and 3/4 that I took for a second try. The minimum contents of a pack contains enough for 3 or 4 wraps. If you buy it off a roll, then you need to know how much to buy and you need to talk to them about their returns policy.
Both nuts on top.
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Old 05-27-2018, 08:10 PM   #15
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Quote:
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I have an image of you trying to force it back together and water is just soaking you under high pressure while your reaching for the hammer. Do you have goggles?
I have had that image as well but I haven't read about anyone experiencing that type of disaster. My take on it was that yes some water comes in but manageable. Should I keep reading?!?!? One of the reasons I will have someone there who has done these before...
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Old 05-27-2018, 08:17 PM   #16
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U should be fine. I was able to change out entire stuffing boxes in water. From conv to dss. Yes, some water came in
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Old 05-27-2018, 08:23 PM   #17
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A stupid advice but be sure to test your pumps BEFORE starting this work
I want to do the same but on the hard before splashing so also wondering what packing material I should use.

L
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Old 05-28-2018, 08:26 AM   #18
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just did this for first time. remove the existing and buy what you currently have.
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Old 05-28-2018, 09:14 AM   #19
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Maybe get a stiff piece of plastic and cut a strip 1/4" wide. Another 3/8" And another 1/2".
Remove the end and see which strip fits best for the size. Put everything back together (snug) and go buy the packing.
I'd want something with a pointy hook on the end to dig out the old packing too.
Take the packing and wrap it around the shaft somewhere and cut it on the diagonal to fit. At least 3 maybe 4 pieces. Or as many as you can get out of the length of packing.

Then have at it !!
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Old 05-28-2018, 04:13 PM   #20
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Quote:
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I have had that image as well but I haven't read about anyone experiencing that type of disaster. My take on it was that yes some water comes in but manageable. Should I keep reading?!?!? One of the reasons I will have someone there who has done these before...
It can spray some water, but not badly, I have done this couple times on my boat too. A deeper hull will have more water pressure on the hull, but you can manage it, your bilge pumps will keep up. The space between prop shaft and shaft log is about 1/8 inch all around at the most.
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