Packing Size for Stuffing Box

[My Cyn]

Hi Guys,

Wanted to inquire the size of the packing used for the stuffing box on your boats.

I recently used 1/4" Gore GFO. It was tight going in. In hind sight, I probably should have used 3/16".

Interested in hearing experiences, good and bad, from the forum.

Cheers,

Bill

[Dolce_Vita]

When I repacked mine two seasons ago, I initially mistakenly used 1/4" packing.  It was tight going in. The stuffing box overheated, over 200 degrees in less than a minute!  Verified with an IR thermometer gun.

I dug it all out and replaced it with 3/16, which went in quite easily.  Now runs cool as can be, just 10 degrees above the water ambient.

I used this opportunity to try out the Gore/Graphite GTU and the moldable dripless packing from Pacific Trading Co.  This stuff works great.  Box runs cool as can be, and has almost no drip.  The lubricants in the moldable packing take the place of the usual slow drip in lubricating the shaft.

[My Cyn]

Thanks for the feedback. The stuffing box is running cool after a bit of adjustment. At the next haul-out, I plan on using 3/16".

Regards,

Bill

[Dolce_Vita]

Just for reference, my shaft is stainless 1 1/8", not the original bronze shaft. 

If you could get the 1/4 adjusted to not heat, them maybe you have a different shaft and/or stuffing box size.  With 1/4" mine was so tight that it would heat up even when I had the packing nut so loose that the shaft rotation would spin it off!

[My Cyn]

Hi Guys,

Wanted to refresh this topic. I took the opportunity today to dig out the 1/4" GoreTex GFO packing I installed last October and replace it with (3) rings of 3/16" GoreTex GFO. I did it with the boat in the water. A bit of bicycle inner tube and a zip tie worked wonders to stem the tide....The bright side was no apparent damage to the shaft from running hot due to excessive friction over the last 11 months. The 1//4" packing I took out looked great. I'll plan on sticking with this brand until experience shows me otherwise. (3) rings of 3/16" provided me with lots of thread engagement on the shaft log, as opposed to a few threads with the 1/4". 

As a side note: I found that a .22 caliber bore brush with brass bristles worked great for cleaning the threads on the nuts  prior to installing the new packing.

Regards,

Bill   

[Sea Haven]

Hey guy's, I gotta chime in here.

Early in the season when I purchased the boat, I took her from the buyers slip on a 12 hour, 63NM trip to where she she's moored now.

Having had dealt with stuffing box issues in the past, I purchased General Tools Infrared Thermometer with Laser Sighting at Home Depot with intent to monitor the stuffing box temp along the way as I see that seems to be the thing to do now a days, makes perfect sense . Despite sellers and surveyors comment, findings, assurances, I always err on the side of caution. Also great to check the block and exhaust temperatures as well!

Ambient temp at the start = water temp 68 deg. Underway, no tach estimating 2K avg rpm, 86-91 deg.

Looked good the whole way. But she did drip quite a bit, every second or so, certainly not 3 a minute per recommendations I see online. After we moored she dripped for a while eventually slowing and coming to a stop.

Happy enough. Everything seemed right with the world,.

Now I don't really care when it comes to stuffing box dripping, other than the spray about the compartment and subsequent corrosion. I NEVER had a stuffing box that dripped less than once every 3 or 4 seconds much less 3x a minute. No matter how I adjust, cursed, yelled and prayed. Thought it's just a way of life to keep the batteries charged for the bilge pump, and replace things back there as they corrode. But I just don't think that's how one should live.

BTW, it seems I read this "new to me" A4 dislikes humid engine compartment and salt mist for a number of reasons. But hey, what's discretionary income for anyway??

Now on to my dismay.

Didn't have a great summer for various reasons that included wiring issues, Carb rebuild (my first and I'm PROUD!!), and a barnacle encrusted prop from sitting too long as I rebuilt the carb. Barnacles were nasty this year.

She motored (not even sailed until this very last weekend) a total of four times since June's homeward bound transit, 3 of which were in the past several weeks since I removed the barnacle cocoon lol.

Now that the tach (which caused an issue that lead to the carb rebuild, another sea story) is installed I have the following readings:
1st attempt two weeks or so ago.
~2000rpm 77 deg ambient I hit as hi as 181 deg. Seemed to sizzle as it continuously dripped. Got real nervous headed back to the mooring at a crawl.
Understand SHE IS DRIPPING VERY HOT WATER!

So I finally got it loose, backed off a bit until water just began to flow , then snugged up until a continuous drip, then just a tad more until a drip every 3-5 seconds. Since I didn't move the jam nut, I noticed she was now only a 1/2 nut face (1/12th from it's last position) Let it sit, she eventually stopped.

I tested her briefly on the mooring, she seemd to warm just a tad to 120deg. She dripped as before, then stopped.

This week I said to heck with it, were going out and spreading this ladies wings!

Took her out, tried not to concern myself with it (yeah right). Just in and out of the harbor, say 20 minutes at 1200 rpm.
Had her first sail (sweet, I soooo needed that lol GREAT confidence builder), started right back up. came in.

Same behavior, quick drip underway, slowing and eventually stopping when off.

Yes I took readings.

~1200 RPM 77deg  ambient still peaking @ 130deg

~2000rpm I hit as hi as 160 deg.

So what does this all mean?

I'm DONE with stuffing boxes, soooooo done. Stick a fork in me done!!
I understand my limitations, the first step in self recovery is admitting a problem....stuffing boxes kick my stern!! lol

I'm crying uncle here. Throwing in the towel, 5 years on a previous boat, now this...dripping AND hot now...REALLY??!!

Sure, repack it...until it does it again.

Yes they have there perks, old easy technology that shouldn't be an issue. I guess I'm just one of those sailors who can't fathom this one item of boating.

This off season I'm having the yard install the dripless PSS Shaft Seal.

TO me it makes perfect sense.
1-My stuffing box hose is old and cracked at the stern. Due for replacement.
2-I can check it a heck of a lot more than required by making an inspection it part of my pre-underway checklist, so I'm ALWAYS cognizant of it's integrity with respect to the rubber boot and stainless rotor.
3-It certainly serves the tight access underneath there much better.
4-The 6-8 year service replacement is fine with me, plus that requires me to perform a more thorough inspection of the drive drain from transmission to prop.
IOW a few more $$ for piece of mind.

Granted, you have the horror stories of boot failure, or rotor failure due to improper installation. Nothing is foolproof nor install and forget. But in the end I'm just tired of constantly fiddling with something that should not have an issue. 90% of my intended sailing area is within Boat US or Sea Tow's help. A bike inner tube tire with zip ties is recommended for PSS Dripless shaft seal failure.

In the end it's what your comfortable with, I'm sure most sailors out there swear to the tried and true packing gland. But I'm no longer one of them.

I would rather check something on a routine basis, follow it's recommended maintenance, be hassle free, than constantly tweek a nut looking for the ever elusive limited drip setting that seems to change with the tide.

Sure it's something simple, but sooo tired of ANOTHER non-issue to worry about.

Again guy's, it's just me. Not knocking anyone's preference or implying one way is better than the other, but I need to try something new here.

Thanks for letting me rant!!

Of course I''ll keep everyone up to date.

When I get to the Annapolis show on 10/12, I'm heading right to the PSS Dripless Booth if anyone cares to meet up.

Yours in sailing.........

"Sub" Ed

SV Sea "Leaky, hot Stuffing box" Haven

[Frayed Knot]

I have a PSS seal.  Love it.  The only drawback is at high RPM it wants to leak.  But my MD11 vibrates a lot at high RPM.  So I don't give her a lot. 

[Sea Haven]

Thanks!

Did you install, or have someone else install?

I'm curious as to the stern tube diameter.

If you ever get the chance, would you mind taking some photo's to share?

Interesting that she wants to leak at your hi-rpm. I wonder if it's the rpm itself, or your motor (and shaft) vibrating in such a manner that defeats the radial or longitudinal tolerances. Oscillating in 3 axis.

But I'm just on the learning curve with it lol

This might help....let us know:

Pss Shaft Sea Leak

Anyway, a lot of users are concerned about catastrophic failure, so here's a neat "You Tube" video covering that.

Emergency Shaft-Seal Repairs

After 4 years aboard a nuke Submarine, I could handle this! lol

"Sub" Ed

[Dolce_Vita]

I have to chime in here with some (admittedly secondhand) info on the PSS that I dug up when I was considering one.

What I have been told is that in shallow muddy bottoms (like we have in abundance here on the Chesapeake), operating in reverse can churn up enough grit from the bottom to get pushed up the shaft tube and into the PSS, causing it to fail to seal, in a big way.  One of the boats here in my marina had this happen to a newly-installed PSS while backing into the slip and (so I'm told) nearly sank the boat.

I ended up going with a combination of the Graph-Tex packing combined with the moldable dripless packing sold by Pacific Trading Co., and I've been extremely happy with the results.  You install a "donut" of the moldable packing, backed with a single ring of the Graph-Tex packing on either side.  The whole thing gets saturated with the supplied synthetic grease.  The results were amazing.  With very little pressure on the packing nut, the drip rate went to zero, yet the assembly runs cool, only heating to 10 degrees above the ambient water temperature.  The synthetic grease and the graphite, rather than the water, supplies the lubrication.

After 3 seasons and 277 hrs of engine use, with no adjustments, I'm just now starting to see some dripping while running.

[selene]

I also have a PSS seal - love it, but nearly lost the boat because of it...

The seal relies on two components (I'll probably get the terminology wrong): a rotor and a seal.  The rotor is a carbon disk which spins against the shaft seal, which is secured to the prop shaft using two grub screws.  The rubber bellows keep the rotor pressed up against the seal, making it watertight; if it does drip - sometimes caused by dirt geting in there - you "burp" the seal by compressing the bellows, water squirts out, clearing any obstruction.

The catch is the two grub screws.  A couple of years ago, I was getting into a slip with moderate wind and current, and so was shifting the gears and needed to gun the engine more than usual.  No biggie.  Tied, up, and as I was checking the boat before leaving her, heard water...no, had not left the hose on...not good.  Leapt down below, to find the bilge was full and the water was rising visibly up towards the cabin sole...yikes! With frantic checking,  I quickly spotted the problem - water was pouring out around the shaft seal.   Remember I mentioned two grub screws?  Well, I should have said two *small* grub screws. locking the shaft seal in place. My guess is that the engine moved slightly between forward and reverse, and it had loosened - and then displaced - the PSS shaft seal, letting the ocean in...and quite a lot of it in a short time...

The moral of this story is PLEASE PLEASE PLACE A SECURE BACKUP COLLAR BEHIND THE PSS SHAFT SEAL!  Cheap insurance.  I used a McMaster-Carr collar (http://www.mcmaster.com/#acme-clamp-on-collars/=oh9wtq); I have seen people use zincs, even hose clamps.  But PLEASE check your installation has some kind of backup beyond the standard PSS shaft seal. An experienced fitter will know this already, but....

I still have cold sweats thinking about it.  If I didn't always check all is secure before leaving the boat...well, you know....

[Sea Haven]

All!
Thanks for all the input.

Ed, as Sea Haven will not regularly see the same conditions as Dolce Vita, I still plan to try the PSS. FWIW, I always check the Engine Compartment not ONLY prior to getting underway, but before I secure for the day. So at least I can keep and eye on it. It's kind of a habit with me, either from my Submariner days where I was trained to take nothing for granted, or just adult OCD. I'll also check it when I kill the engine when anchored, moored or docked in an unknown location, especially in shallow, muddy locations. We have quite a lot of that in the Great South Bay of Long Island's southern shore. Mean depth is 8ft with 2 ft of black muck! Thanks!!

Selene, Thanks as well. The back up collar seems to be a common security measure in all the threads I've read about it. I plan to have it installed. BTW, McMaster Carr is the bomb lol!! Since two is one, and one is none when it comes to boating, I plan to put a secondary bilge switch wired to a LOUD, distinctive alarm. I'll install it above the existing bilge switch so I don't get false positives and I'll know the existing pump is either NOT working or keeping up with the flooding.

"Sub" Ed
The belts and suspenders Mariner.