Packing

[Hermit Scott]

The engine, prop shaft and packing housing is not original on my boat so I can't look it up.
I don't know what size I am supposed to repack it with. Also I would love to know what the best kind is, gortex, kevlar, etc. I had to replace the prop, prop shaft and coupling, so I have to hold off on the PSS seal.
So I am left repacking this ...for now.
The threads are 1-7/16" outside diameter on the threaded part that accepts the packing nut. And a 1" shaft. In the picture the width of that packing is either a smashed out 3/16" or a smashed in 1/4". Very nearly in between the two measurements.

 

[Ross]

Probably 3/16"

 

[Rich (P303)]

Check Maine Sails links to his projects... You'll find it pretty professional and informative!

I had the same problem... I smashed in 3 rings of 1/4" in... but was running hot. I was hanging by my toes upside down into the locker wedged in between the HW and fuel tanks... measuring was out.

Pulled the 3 rings out and put 4 rings of 3/16"... still running hot. That was another problem as the reason it was running hot was there was some play between the shaft and shaft coupler... the 2 set screws were wired lose!

In retrospect... I could of compressed the 1/4" some before I tried to slide it in with that half piece of PVC. I think it got hung up and rolled on me.

I have a 1" shaft. Get that black synthetic stuff. They sell it by the foot.

Good luck.



Get that black stuff.

Get the Gore stuff...

 

[Maine Sail]

Based on your measurements it should be a 7/32 packing but I don't think they make it.

A box that uses 1/4" packing will have male or female threads of roughly 1 1/2" on a 1" shaft.

A box that uses 3/16" packing will have male or female threads closer to 1 3/8" on a 1" shaft. Check your measurement of the male or female thread again just to be sure..

I would use Gore GFO or Western Pacific Tradings GTU packing but they only come in 3/16 or 1/4 so double check your measurements..

 

[Hermit Scott]

shaft thread measurements

It is about 12 thousanths under 1 1/2". I will take it to be 1/4" packing.
I did review mainesails conventional packing and the dripless install.I was planning to do alot of things wrong until I read those and learned otherwise.
The female threads are 1 7/16".

 

[Maine Sail]

It is about 12 thousanths under 1 1/2". I will take it to be 1/4" packing.
I did review mainesails conventional packing and the dripless install.I was planning to do alot of things wrong until I read those and learned otherwise.

Sounds like 1/4"..?

 

[Hermit Scott]

threads

The threads overlap. I remeasured and then again.

 

[Hermit Scott]

how did you know what size your C36 took when you changed them out?
I am always amazed when people are willing to help me for nothing in return.

 

[Maine Sail]

how did you know what size your C36 took when you changed them out?

Math!

I am always amazed when people are willing to help me for nothing in return.

I'm just siting here doing rather mundane paperwork. This banter is a good time out.!

So...

Measure the od of the male threads of the shaft log or the id of the stuffing nut as shown below. As you can see I have roughly 1 3/8 inches. Then subtract the shaft diameter from the total id or od.

1.38" - 1" = .38" now divide that number by two and you get .19" or as close as you'll get to 3/16" or .1875"

(.38", or .19" after dividing, is about as close as you get to .375 or 3/8" or .1875 or 3/16") .

Do me a favor and use the knife blade ends of your calipers and measure across the bottom valleys of the male threads instead of the peaks. This should more closely match the ID of the nut.

1 1/2" diameter minus 1 7/16" equals a 1/16" difference. So your thread depth should measure 1/32". Either way it's still a 1/4" packing not a 3/16". 3/16" would be too sloppy.

 

[Hermit Scott]

yup

You are correct about that, I was measuring the peaks of the threads on the male and feamle.

 

[Chris Burti]

For the rest of us who are technically challenged with math...

To determine packing size in a low tech fashion, slide drill bits between the shaft and the gland until you determine the size of the gap. Make sure that the shaft is centered.

FWIW Catalina has recommended both the 1/4" and 3/16" diameter packing in different versions of the C-320 literature and in response to queries from members of our owner's association, so we've had a lot of discussion on the subject. As we C-320 owners also have a 1" OEM shaft, I'd guess the gland is likely to be the same part on the C-30 and all other Catalinas with a 1" OEM shaft.

Our owner's group has found that both the 1/4" and 3/16" sizes work well, but you may find it easier to compress two rings of 1/4" with the compression nut before adding the third as some have found it hard to get the nut started on the threads with three fresh 1/4 rings. I think this supports the math solution that indicates the correct packing size is actually between the two available sizes. I did my change out on our C-320 at the slip In order to minimize the water influx, I pre cut my rings by wrapping the packing around the shaft and cutting both ends simultaneously on the diagonal with a razor knife. Don't forget to stagger the joints.

The GFO packing can be picked up inexpensively in a local industrial supply store and I have found it to work flawlessly with a resulting dry bilge in operation over four years now. As it is essentially self lubricating, it does not need repeated annual compressing as does flax packing and does not seem to wear out at anywhere near the rate of impregnated flax.

 

[Hermit Scott]

packing, shaft and prop painting?

I almost bought some 'gore' packing last night. After entering my credit card info, I paused to go back and read the description. It was a gore and carbon fiber mix. So I went to another company and paid a little more for the stuff I believe to be 100% gore. It was $20 shipping included for 2' of 1/4". My wife bought a shaft and I told my wife to get aquamet 19 if they had it but they gave her aquamet 17. Aquamet 19 is a version of 304 stainless that is nonmagnetic. The 17 is magnetic stainless. This concerns me. I am having a stainless coupling made so I won't have the same problem seperating the shaft from the coupling next time. But I am not sure how the magnetic stainless will do in the salt water. Most of us don't haul in the winter down here. So we have to keep an eye on our zincs.
This is my question. Do you guys paint your shafts and props with primer and bottom paint? I don't want to paint the shaft because then I won't be able to easily remove it later through the new cutlass bearing. But crap grows sooo fast down here. I don't know what to do.

 

[Bob S]

McMaster Carr

sells 100% GFO Expanded PTFE compression packing in from 1/8 to 1/2 by 1/16ths
A 5' piece of 3/16 is 25.16, the 1/4" is 38.96.

Are these considered good prices?

 

[Deadline]

Re: McMaster Carr

If your shaft is one-inch, you need 1/4 inch flax.
3/8ths will fit nicely but leak interminably. Trust me.
Here's the short course in stuffing box replacement...

REMOVAL
Unscrew thin brass jam nut to free up big one
Unscrew big brass nut completely.
Spray WD-40 inside to loosen up flax.
Turn corkscrew pick into first layer, pull Vise Grip offers better leverage
Repeat until all layers removed two if was chinzy, three more likely, four if anal
Clear out brass seating of any loose debris so new flax sits well

INSTALL
Buy 13 inches Teflon 1/ inch = three at inches
Turn first wrap tight, mark with thumbnail or do at home with 1-inch stanchion
Cut with share razor knife or Dremel saw
Cut remaining 2 wraps to same size
Poke first one in clockwise by turning big nut slowly
Mark where it started with red pen
Screw down onto shaft to pack, by hand only
Loosen and repeat two more times
Do not overtighten, or will burn flax and not seat properly

TESTING
When launch, be prepared to tighten using wrench keep jam nut loose
Should be no drips at rest, do not overtighten
In gear, should be no more than 1-3 drops per minute preferably none
Optimum is no drips in gear “1-3 is an old wives tale,” says Fred at Yard
Tighten one flat at a time while in gear
If the big nut is warm, back off as too tight burning the flax,unlikely at this point
Always retighten the jam cleat to avoid inadvertent loosening
When it’s right, try a day or week later takes time, be patient
Check again for three weeks then three months later
Should last three or four years okay to tighten one flat a time, over time

 

[Maine Sail]

If your shaft is one-inch, you need 1/4 inch flax.

This is NOT always true (See photo above of 1 3/8" ID packing nut & the math that goes with it) MANY packing boxes for a 1" shaft are designed for 3/16" packing NOT 1/4". If you put 1/4" in a 3/16" box you run the risk of over heating and premature shaft wear.

In gear, should be no more than 1-3 drops per minute preferably none
Optimum is no drips in gear “1-3 is an old wives tale,” says Fred at Yard

Be very careful listening to Deadline's "Fred at the yard story" & trying for no drips in gear. While you may be able to do this, eventually, and after a proper break in, with a brand new shaft, and GFO it should never be done with traditional flax even the teflon impregnated stuff. Gore GFO is intended to have very minimal dripping and considerably less than other packing types but they specifically do not say to adjust it for no drips.

GFO is NOT 100% DRIP FREE and it DOES NOT claim to be!! Yes you can, in many situations, make it drip free at rest but it is still intended to drip, all be it slightly, and run cool when the shaft is spinning.

In the Gore GFO marine instruction they just say to adjust it to the desired leakage. It still needs a little water to lubricate and this is usually less than a traditional based flax whether it be Teflon impregnated or paraffin based lubrication.

If you're going to stay with a traditional flax based system the GORE GFO is by far the best flax you can buy. The white Teflon impregnated flax is NOT GFO. It is regular flax with PTFE instead of a paraffin based lubricant only. GFO is blackish gray in color the teflon impregnated stuff is white to off white.

GFO Marine Instructions:

AFTER THE LAST RING IS INSTALLED, take up bolts finger tight. Do not jam the packing
into place by excessive gland loading. Make sure gland bolts are taken up evenly. STOPPING
LEAKAGE ENTIRELY AT THIS POINT WILL CAUSE THE PACKING TO BURN UP. Run
the vessel for 5-10 hours and readjust packing to get desired leakage.

Please note that it says DESIRED LEAKAGE!!!! Not "adjust for NO DRIPS!!!"

 

[sailingdog]

Umm... the key words in the GFO instructions are:

STOPPING LEAKAGE ENTIRELY AT THIS POINT WILL CAUSE THE PACKING TO BURN UP.