where is my grease going?

[leechips]

Hi
recently got a jeanneau fantasia and when it went back into the water the stern gland started leaking about a drop every 2 seconds while underway. I decided to add some grease since I did not know how well it had been done previously but I have added 2 tubs of grease and it will still take more. The gland is by the way still leaking. I assume I will have to repack the gland which I will do when she dries on a spring tide but.... where is my grease going? Why can I seemingly add more a and more. any help???? I know little about these things.



<hr width=100% size=1>

 

[roger]

You dont say where you are adding the grease. If you have a remote greaser it may be leaking out on the way to the greaser. - nasty thought.
Shaft seals should ( I think) have two sets of rings between which the grease is pumped. Alternatively you might have just the inboard set - in which case the grease could be going down the propeller tube.
Can you get information on the design of greaser used on your boat?
Repacking is not much fun when under time pressure. If you dont think the leak is going to increas dramatically it might be a job for next winter.
I'm not happy about that suggestion someone else may have a better idea.

<hr width=100% size=1>Roger

 

[leechips]

the stern gland is the traditional type with industrial hose used connected to a tude with a large nut on the end. I am adding grease to a hole in the top of the tube with a screw on it to pack the grease down. What happens inside the tube I dont know!! I know if I undo the nut I can get at the packing to replace it. But I am concerned about where the grease is going. What is stopping the grease going the other way away from the packing and down the shaft and into the water?

<hr width=100% size=1>

 

[AndrewB]

Down the shaft is the only place it can be going, if you can't see it oozing out inside the boat.

It ought to be squeezing in around about the second (middle) ring of your stuffing. In time it then spreads throughout the stuffing and works down out past the shaft, but the stuffing itself should prevent you being able to just shove in tubs of the stuff. That and the quite fast leak suggests all is not well with your stuffing, specially the bottom rings. Maybe the lowest one wasn't pushed down to the bottom of the stuffing box.

As you say, get the old stuffing out next time the boat dries out and my guess is that all will be revealed. Provided access is good this is an easy inter-tide job, but make sure you have the correct sized replacement stuffing to hand before starting! Apart from the leak, I don't think there is any urgency about doing this though.

<hr width=100% size=1>

 

[Alpha22]

I took mine appart last year and there is nothing stoping the grease from going down into the water.

Just one set of packing rings and the greese injection point is on the water side of these. I assume the water presure (not much) pushes the grease into the packing.

You could continue packing with greese untill the whole marina was full!!

D.

<hr width=100% size=1>Last weekend was shopping darling........ so this weekend is boating. (Duck!)

 

[brianhumber]

Grease and packing rings is a very old but simple way of prevent excessive water entering into engine rooms from pump and shaft glands. On yacht stern tubes the outer rings are often missed due to the restricted space and small pressures involved. In fact impregnated packing rings where the correct leakage is set up by the gland nut or follower nuts( about a drip per minute when running) will last for years. The greaser is added to a) counter over enthaustic tightening of the nut leading to heat running out the impregnated lubricant mediuim, b) when the shaft is stopped the grease seals/plugs the gap tween shaft and packing which woud lead to an increased drip rate when the shaft is stationary, if this grease were not added.
As time passed more exeotic packing was developed and used ie PTFE which did not require grease.

In your case either the greaser tube is split and you are pumping grease in the bilge or the grease is missing the seaward end of the rings and is being pushed out to sea.
If your nut is hard against the tube then it indicates the packing is worn and should be replaced.

Brian

<hr width=100% size=1>

 

[leechips]

thanks for all that!!! I will wait and see how bad it gets before deciding to do it on a tide. Besdies I dont know what sizre the packing is. Will stop wasting money on grease though!!!

Lee

<hr width=100% size=1>

 

[l'escargot]

If the nut isn't hard against the tube, loosen off the lock nut and tighten it down half a turn to compress the packing.

<hr width=100% size=1>

 

[webcraft]

When I took my prop shaft out this year the stern tube was full of grease . . . doesn't seem to do any harm, in fact I think it acts as a seal and stops water getting up the stern tube.

- Nick



<hr width=100% size=1><font size=1><A target="_blank" HREF=http://www.bluemoment.com>http://www.bluemoment.com</A></font size=1>

 

[TonyBrooks]

Most, if not all, the stern gear I have seen use grease to lubricate the bearing that should be behind the packing. On the flexible (hose between gland and tube) glands this "bearing" may be very narrow and its more likely that the grease is injected into the packing.

Once we get onto rigid glands (no hose) the situation becomes more complex. Unless a means of feeding water into the inboard bearing is provided, that bearing is most likley to be a plain metal (white metal/bronze) bearing which will require plenty of lubricant, the outboard bearing (on a modern deep water boat - as opposed to ditch crawlers) may well be rubber or plastic that is water lubricated.

In this case, pushing excesive ammounts of grease into the stern tube could (not would) attack and degrade the outboard bearing, so care should be taken - turn greaser down until it stuiffens and then stop.

On older and traditional boats, plus the ditch crawlers the outboard bearing is likley to be anothe plain metal bearing so lots of lubricant is required, not only for lubricatuion purposes, but also, in the case of shallow water boats, to expell any mud or grit that may have found its way into the outboard bearing. In this case I would fit a proper remote greaser (brass tube with screw down T handle) and turn it untill it stiffens and then at least another two turns.

In answer to the original post, the most likley place the grease is going is into the ogging - look for blobs floating up downstream of the boat

Tony Brooks

<hr width=100% size=1>