Shaft Packing

[Mac G]

As someone new to powerboating am going to ask you experts a lot of stupid questions, but please bear with me as this is how I learn:

Have twin 135HP diesels with conventional bronze shaft packing glands.
1.5 Inch bronze shafts.
Cruise at 1700-1800 RPM.
Shaft logs appear to be cooled with rawwater from the heat exchanger that feeds a rubber boot behind the adjustment nuts.

Question:
What type of packing material do you recommend?
How often do you inspect it?
How often should I replace it?

Please advise

Thank you

 

[Mac G]

for context, am here from sailboat background where have only dealt with small HP engines with SS shafts that were not used all day every day like we do now. So am curious what you all use and recommend motoring full time and whether having bronze shafts makes any difference.

Thank you

 

[Comodave]

I like Duramax packing. Once you get it broken in you can adjust it so it doesn’t leak at all. I have not seen bronze shafts.

 

[Mac G]

Thanks Dave
How often do you replace it?

 

[rslifkin]

For my last repack I stayed on the "avoid graphite" side of the fence and went with a teflon impregnated acrylic packing (Palmetto 1347AF). It was cheap, it's held up well so far, and it can be adjusted to barely drip without getting hot. I get a slight dampness but very rarely a drip when sitting, occasional drips at slow cruise, and a bit of dripping (but nothing excessive) at fast cruise. I've got the same packing in the rudder posts and for those I also packed in some heavy marine grease. After adding the grease, I had less friction in the steering and found it easier to get the packing adjusted for no drips at all from the rudders.

Replacement for packing is no different than a sailboat. It only needs replacement when it's worn enough that either you can't avoid excessive dripping or are having to adjust the packing more and more frequently. Depending on the shaft, packing, stuffing box, etc. you may get a few hundred hours or 1000+ hours between repacks.

Personally, I carry the tools and spare packing for a re-pack on board, so if I see the need for a repack coming up, I can just do it and worry about getting more packing later.

 

[Comodave]

The PO of that boat had it installed and was in there for about 10 years. I had the engines out to work in the bilge so I went ahead and rebuilt the shaft log, new hose, clamps and packing. But there wasn’t anything wrong with the packing but the hoses looked to be in poor shape so I rebuilt the whole thing.

 

[Mac G]

Thank you Gentlemen
will replace this spring as mine is of unknown age.

 

[Mac G]

even though not dripping now...
will start fresh with known date

 

[Mischief Managed]

Another vote for Duramax packing. Three years with mine and it seems great.

 

[Comodave]

Duramax does have graphite in it but when I pulled it out after 10+ years the shaft was in perfect condition. You can adjust it so there are no drips at all and it works fine, just have to follow a simple breakin period. You gradually tighten it over the first 10 hours. They advertise a 5 times longer life than traditional packing and I believe it since it was over 10 years old when I took it out and it was in good condition.

 

[PhilPB]

I like Duramax packing. Once you get it broken in you can adjust it so it doesn’t leak at all. I have not seen bronze shafts.

I "had" a bronze shaft. When the restoration/repair company that I hired to replace the cutlass bearing couldn't liberate the shaft from the tranny coupling , they ended up cutting the shaft to remove it. That inexpensive cutlass bearing ended up costing me to install a new ss shaft, coupling, midshaft bearing and a whole bunch more! Long story short....I saw that I had a bronze shaft. Should have had it melted down and sold. Not sure how much a cutlass bearing replacement usually costs but mine, including some additional work cost about $15k us.

 

[kapnd]

Duramax does have graphite in it but when I pulled it out after 10+ years the shaft was in perfect condition. You can adjust it so there are no drips at all and it works fine, just have to follow a simple breakin period. You gradually tighten it over the first 10 hours. They advertise a 5 times longer life than traditional packing and I believe it since it was over 10 years old when I took it out and it was in good condition.

I’ve used Duramax for about 10 years also, and GFO on other boats I work on, with no problems at all from the graphite.
Damage might occur if the stuff were left idle for a long period of time in salt water, but that also goes for any type of packing.
I really appreciate the simplicity of a traditional packing gland, and having it drip free is icing on the cake!

 

[Circumnavigator]

I strongly recommend getting an infrared laser pointer remote thermometer. I first got one for Fintry (5.5" shaft, whose shaft log is filled with Stern Tube Lubricant) and it allowed me to feel comfortable tightening the packing considerably. The same was true on Morning Light -- no dripping with traditional flax packing and temps never above 130F. It's also handy if you suspect that an engine temp gauge is misbehaving.


$20 or less from Amazon.


Jim


Sweetwater - Swan 57 sloop - circumnavigated 1995-98
Fintry - x Royal Navy Fleet Tender 2003-22 20k miles including x-Atlantic The Fleet Tender Fintry
Morning Light -- Webbers Cove 42 trawler 2021- 23
[FONT=&quot]Going back to sailing now that Morning Light is sold.[/FONT]

 

[psneeld]

I "had" a bronze shaft. When the restoration/repair company that I hired to replace the cutlass bearing couldn't liberate the shaft from the tranny coupling , they ended up cutting the shaft to remove it. That inexpensive cutlass bearing ended up costing me to install a new ss shaft, coupling, midshaft bearing and a whole bunch more! Long story short....I saw that I had a bronze shaft. Should have had it melted down and sold. Not sure how much a cutlass bearing replacement usually costs but mine, including some additional work cost about $15k us.

Wow...sounds strange...cutting off the coupling is usually easy, fast and done right leaves no damage to the shaft.

Wonder why you had to have all that done?

 

[Max1]

Hi. Relatively new boater myself, and one of my first jobs was to repack the packing gland on my Marine Trader 36. I also felt like I didn't know what I was doing but the learning curve is steep.
I also used Duramax and it's been in the boat for the last two seasons of cruising. Last fall I removed it all to inspect for wear, and found that it is still in pristine condition. I will be reinstalling it this spring.
By the way, when I was learning about repacking, I also heard that syntef is a good packing lube. I purchased some when I purchased the Duramax, though I believe the Duramax is Teflon and impregnated and doesn't need it? Regardless I will be coating it with syntef when I reinstall in the spring.

 

[kapnd]

I use Syntef liberally all over everything when installing packing, it fills any voids, and helps lubricate the shaft during the critical moments of initial startup.
I would not reinstall the old packing, the cost is minimal, and cheap insurance, same as an impeller.

 

[Comodave]

Agree on not reusing the old packing. Put new in and be done with it for many years.

 

[C lectric]

I repacked my stuffing box close ten to 15 yrs ago with GOrtex GFO packing. It is still in use and only needs a slight tightening every year. I don't try to stop all water ingress but keep it down to a bare minimum.