Stuffing box not dripping

[Tmacmi]

I had the yard re-stuff the stuffing box this season. It was a tight fit but they got 3 loops in. When I ran it, no water was coming through the stuffing to lubricate it. I put a few hours (10 or so) on the engine to see if that helped bed them and allow for a few drops of water every minute.

Didn't work.

I then tried to loosen the nut, thinking it was too tight. As soon as I did water started coming in the thread side.

I let the yard know and they tried removing 1 wrap, leaving 2, and no water.

They removed another wrap, leaving one, and after about 3 more operating hours there is still no water coming through the stuffing and the shaft.

The yard said they haven't seen anything like it.

Its simple 1/4" PTFE Flax. Also a brand new shaft.

Before installation I measured the interior diameter of the nut vs. the shaft and it was slightly, very slightly smaller than 1/4", but certainly not 3/16.

Any suggestions?

[rslifkin]

I'd personally adjust it to just tight enough that it stops leaking with the shaft stopped. Then go motor around for a bit and monitor temperature. Hopefully it'll at least weep a little bit of water, but for the most part, as long as it's not getting too warm while motoring, it'll likely be fine.

[a64pilot]

I’ve had PTFE packing for at least three years now, and it doesn’t leak.
The issue is does it get more than warm to the touch, if it does then you have a problem and need to fix it.
First out of the yard mine got HOT, so I backed off on it and it didn’t get hot anymore and I left it alone.
Underway it will get a wet ring where it normally drips, but a drop doesn’t fall. I have not had to adjust it at all in three years.

This year I’m likely to go to a dripless deal just because, and I’m a little concerned with what may be going on under the packing as I’ve not seen one that didn’t drip before, but I’ve not used Teflon packing either.

For some reason Teflon packing isn’t common?

[wingless]

The dripless seal carriers on my boat require cooling water flow during operation. This water flow is provided by the operating engine(s).

If using a dripless seal on a sailing boat, ensure that the cooling requirements are satisfied.

[rslifkin]

Originally Posted by a64pilot

I’ve had PTFE packing for at least three years now, and it doesn’t leak.
The issue is does it get more than warm to the touch, if it does then you have a problem and need to fix it.
First out of the yard mine got HOT, so I backed off on it and it didn’t get hot anymore and I left it alone.
Underway it will get a wet ring where it normally drips, but a drop doesn’t fall. I have not had to adjust it at all in three years.

This year I’m likely to go to a dripless deal just because, and I’m a little concerned with what may be going on under the packing as I’ve not seen one that didn’t drip before, but I’ve not used Teflon packing either.

For some reason Teflon packing isn’t common?

I'm having a similar experience with the acrylic yarn PTFE packing I put in this winter (Palmetto 1347AF). Drips a little while moving, but not much and just stays damp but doesn't really drip while sitting.

[Tmacmi]

I'll grab my heat gun and see the result.

How hot is too hot?

[rslifkin]

If it's more than about 30 degrees above outside water temp or too hot to hold your hand on, then I'd consider it too hot. If it's just warm to the touch, it's fine.

[a64pilot]

Originally Posted by wingless

The dripless seal carriers on my boat require cooling water flow during operation. This water flow is provided by the operating engine(s).

If using a dripless seal on a sailing boat, ensure that the cooling requirements are satisfied.

I spoke with the manufacturer, and their answer didn’t fill me with confidence, so I’m just going to run the cooling line. It’s just too easy not to.
Their answer was it depends on the size of the grooves in the Cutless bearing and to monitor the seal temp and if it stays cold your good, but if it heats up, then you have to run the line, so I’m just going to run the line.

My seal is real difficult to get to, requires me to pull everything out of storage in the second Stateroom, and that’s more work than running the line.

[a64pilot]

Originally Posted by Tmacmi

I'll grab my heat gun and see the result.

How hot is too hot?

Uncomfortable to hold for an extended time is too hot in my opinion, just a little warm is OK.
I’d go with 30 degrees above water temp, sounds about right as a max

[Tmacmi]

Originally Posted by rslifkin

If it's more than about 30 degrees above outside water temp or too hot to hold your hand on, then I'd consider it too hot. If it's just warm to the touch, it's fine.

Good thing my water temp is 65 degrees and 72 degrees max during the season.

[SV Tru]

More about dripless seals: Cooling water injected into the seal comes from either the engine or a thru-hull scoop (another hole in boat?). With the engine providing the water, obviously if the engine is not on then no cooling water flows. So if your engine is off make sure your prop shaft is not turning. I have discussed with a shaft seal supplier below what shaft rpm and with no water flow, can a the seal be damaged and the answer is they don't know. No turning...no problem.

[Sailmonkey]

Originally Posted by a64pilot

I spoke with the manufacturer, and their answer didn’t fill me with confidence, so I’m just going to run the cooling line. It’s just too easy not to.
Their answer was it depends on the size of the grooves in the Cutless bearing and to monitor the seal temp and if it stays cold your good, but if it heats up, then you have to run the line, so I’m just going to run the line.

My seal is real difficult to get to, requires me to pull everything out of storage in the second Stateroom, and that’s more work than running the line.

I ran a water injection line to ours (installed in the deadwood like yours) just to keep fresh water running through the cutlass. I figured fresh oxygenated water pumped into the whole mess was way better than something septic filled with ooze from muddy water. 12 years like this and everything stays clean in the deadwood and the previous cutlass lasted 10 years and over a thousand hours.

[Fishbust]

I just experienced the same thing with new ptfe packing. I got 3 rings in there no problem and hand tightened only 1 flat.

It gets a little moist but doesn’t drip. Been monitoring it closely and I shoot it with a temp gun after returning to mooring and it typically is around 20 degrees warmer than the water. Warm but not hot.

Last year the old wax packing leaked like a siv and once in a while the loud bilge pump would come on in the middle of the night, so if this ptfe packing not leaking is the new way, no complaints here.

[robert sailor]

I’ve always gone by the idea that if you can hold your hand on the stuffing box when it’s running at normal rpm then the temp is fine, if you can’t then release some of the tension until you can. Most of the adjustments are quite sensitive and you shouldn’t need to adjust the nuts very much. It’s common to get less packing in when you first replace it but often over time you can add another layer. Years ago some brands of Teflon packing were sold as dripless. As long as your not getting excessive heat the stuffing box is being properly cooled.

[Scorpius]

I was told by one "expert" to use the old-fashioned linen packing because PTFE (Teflon) is harder and will wear the shaft much more than linen.