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Go Back   SailNet Community > On Board > Gear & Maintenance > Help with packing problem
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Topic Review (Newest First)
08-12-2010 03:16 PM
CaptainForce As Vasco implies, the temperature of the water can be a factor; however, I am quite satisfied running my engine for a long term and feeling the stuffing box to be warm. I don't tighten it to the degree that would couse it to be uncomfortable when keeping my hand tight against it, but warm is acceptable and not an indicator of damage. Take care and joy, Aythya crew
08-12-2010 02:00 PM
Vasco It should not be even warm to the touch. It should be the same temperature as the seawater. Up here on Lake Ontario my stuffing box is always cold to the touch.
08-12-2010 01:43 PM
sailingdog From Maine Sail's excellent article on re-packing a stuffing box:

Quote:
Aim for 15-20 degrees warmer than the ocean or lake temp but a little higher, with GFO, will not "kill the deal". Some boxes will even drip when the shaft is not spinning and this can be entirely normal depending on the condition of your shaft. Do not get in the habit of tightening the stuffing box when "leaving the boat"! The flax packings are not elastic and do have a memory, in a sense, and they will not necessarily return to their uncompressed state. Doing this will severely shorten the life of your packing and it will start leaking continuously in short order. I don't like "rules of thumb" for drip rates and really hesitated to even put one on here. My reason for this is that every shaft has differing levels of wear and thus the drip rates are usually different in every installation. The best rule of thumb I've found over the years is the least amount of drips when the shaft is spinning but before the box develops any heat. Again, it's drip to heat and little to NO heat is the most desirable. Traditional flax packing can drip as little as about 5-10 drops a minute if adjusted correctly, while running, and this drip rate allows lubrication of the shaft. Do not make adjustments to packing nut, with traditional flax, for at least 24 hours as the packing will swell and can overheat the stuffing box. Pre-mature tightening of traditional flax can result in potential damage. A good and safe practice is to adjust the packing by "half a flat" turns after two hours of use or until you have your drip to heat ration correct. I actually use an infrared thermometer to make this adjustment process easier.
BTW, I generally aim for having the stuffing box basically at the temperature of the shaft... or basically almost no heat, and rely on the bilge pumps to deal with any dripping that occurs either in use or at rest. I'd point out that I don't have a stuffing box on my boat, and have only had to do this on boats that friends of mine have owned.
08-12-2010 01:39 PM
SEMIJim
Quote:
Originally Posted by DrB View Post
SD and/or others,

Curious to as to what everyone believes is "heats up noticeably" when referring to a SB.
I think I'm well-positioned to take this one

When I first installed Gore GTU (or GFO, don't recall which) season before last, I was interested in getting the drip rate to as close to the once-every-20-seconds recommendation as humanly possible. It was at 1/10-secs. To make a long story short: Couldn't do it. It was either 1/10-secs. or so, or (nearly) none at all, and I'm talkin' just a slight >< change in packing gland nut tightness. In my experiments I once had a synapse lapse and, after having tightened the nut just one RCH, forgot to subsequently check the drip rate until after we'd been under way on the iron genny for quite some time. Remembered. Went down and checked. No drip at all! Felt the stuffing box. Not just warm, but HOT! Luckily there was a public seawall marina right there, so we quickly pulled her over, tied up and I addressed the situation.

When the packing gland was dripping again, it dripped gray.

Another time, when the drip rate was really slow, after one of these adjustments, like one every minute, the stuffing box was noticeably warm to the touch, but not hot.

When it's dripping at about one every 10 sec. or so, it's not even noticeably warm to the touch.

Fast-forward to this spring, when the stuffing box coupling hose was replaced by our yard. He made it slightly longer than the old one, so the packing material would be on a different part of the shaft, but he said it hadn't been necessary as the shaft was un-scored, and, he said, the packing material looked essentially brand new, so he re-used it.

That Gore stuff is remarkable.

Jim
08-12-2010 01:19 PM
DrB
Boundarys on Hot

Quote:
Originally Posted by sailingdog View Post
Yes, but on many boats, the stuffing box will drip very slowly when the shaft is not turning. If the stuffing box heats up noticeably when you're motoring, then it isn't being lubricated sufficiently—and you must adjust the stuffing box for when it is turning—and if it drips when the shaft isn't rotating, you just have to live with it.
SD and/or others,

Curious to as to what everyone believes is "heats up noticeably" when referring to a SB. Are we talking warm to the touch, hot to the touch, a few degrees above the water temp? My SB is pretty tight as in it doesn't let in water at all when at rest. I don't know what the drip rate is, maybe a drip or two every 1 to 2 minutes when running, but after the shaft has been turning for a several minutes, the SB area doesn't feel different than the shaft a few inches above it or the coupling. Not too concerned about my set-up, just curious on the "heats up noticeably" comment.

FWIW, I am running the West Marine GTU Gore Shaft Packing Material as my SB packing. 4 wraps.
08-12-2010 11:59 AM
sailingdog Yes, but on many boats, the stuffing box will drip very slowly when the shaft is not turning. If the stuffing box heats up noticeably when you're motoring, then it isn't being lubricated sufficiently—and you must adjust the stuffing box for when it is turning—and if it drips when the shaft isn't rotating, you just have to live with it.

Quote:
Originally Posted by remetau View Post
Ours does not drip when the shaft is not turning.

This is from Don Casey:

"Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning."
08-12-2010 11:51 AM
SEMIJim
Quote:
Originally Posted by stevemac00 View Post
Thanks for the humility Jim.
Wasn't trying to humble you. Was trying to keep you from damaging your boat, possibly leaving yourself stranded somewhere, possibly putting yourself at the mercy of a boatyard with less-than-honourable intentions for emergency repairs, or expen$ive repairs even at a good yard.

Quote:
Originally Posted by stevemac00 View Post
Since the inspection of the packing looked good I hesitated putting in the 1/4. It was a tight fit but I was able to get it in using the side of a wrench.
Without knowing your definition of "tight," I don't know if it was right or wrong. In the end I have to go back to your OP, where you wrote "...3/16 ... didn't quite fill the gap between the nut and shaft ..." and that you basically "stacked" one ring outside the other.

The packing material shouldn't be "tight," per se, but it should fill the gap between the outside of the shaft and the inside of the stuffing box. Otherwise: How could it possibly seal?

Quote:
Originally Posted by stevemac00 View Post
After each strip I tightened the nut up to push it in.
That can work, but it's kind of painstaking, and you run the chance of not ending-up with the joints in each ring offset from one another.

Main Sail, I think it is, recommends fabricating a "pusher" out of rigid PVC. I just pushed mine in, gently and carefully, with a large-ish flat-bladed screw driver.

Quote:
Originally Posted by stevemac00 View Post
I got three strips installed and hand tightened slightly.
Sounds right to me!

Quote:
Originally Posted by stevemac00 View Post
I'm still unclear what caused the bronze dust.
Probably hard to do, but it sure would've been interesting to see the inside of your stuffing box. My guess is it's real shiny and has an ever-so-slightly larger i.d.

Hope the new packing material has you fixed up, and I apologize for coming across poorly.

You might care to peruse Main Sail's Re-Packing A Traditional Stuffing Box. Very informative.

Jim
08-12-2010 11:43 AM
remetau Ours does not drip when the shaft is not turning.

This is from Don Casey:

"Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning."
08-12-2010 11:38 AM
sailingdog I'd point out that if you're using a traditional stuffing box, regardless of the packing material, and it isn't DRIPPING...then you've overtightened more likely than not and are probably scoring the shaft. A traditional stuffing box NEEDS WATER as a lubricant, and if it isn't dripping at least a little bit, especially when the shaft is turning—it is probably running DRY. Even the GFO Goretex packing material REQUIRES SOME WATER PASSING THROUGH IT.
08-12-2010 10:28 AM
stevemac00 Thanks for the humility Jim. In case others read this, here's what we learned. We were told our boat uses 3/16. The last time marina serviced the packing they used 3/16. Another PSC owner used 3/16. So I bought 3/16. I also bought 1/4 just in case because I knew it was likely we would be unable to have access to supplies at times.

I was able to get to a dock lastnight and remove the old 3/16 packing. It looked in perfect shape and came off without any fraying I could find. (Not much water came in and I just wrapped a towel around the shaft so it would drip instead of spraying.)

Since the inspection of the packing looked good I hesitated putting in the 1/4. It was a tight fit but I was able to get it in using the side of a wrench. After each strip I tightened the nut up to push it in. I got three strips installed and hand tightened slightly. Today there is no water dripping but I'll recheck after break in. The shaft is not hot nor was it scored.

I'm still unclear what caused the bronze dust. Perhaps there was a small piece of thread caught on the shaft and turning in the nut.
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