Weeping around the stern gland... What action?

Captain Crisp

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Hi, I've noticed that my stern gland is weeping where it exits the hull. It's letting in about a drop every 5 seconds. Is there anything I can do while afloat?
Thanks,
Crisp
 

dansaskip

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Depends very much on your type of stern gland and were actually it is leaking. "Old fashioned stern glands' i.e. those with packing in are meant to leak a little (to stop them running too hot and or/damaging the prop shaft) but perhaps 1 drip in 5 secs is a bit too fast. However if its this type with packing it should have some means of adjusting to lessen the leakage. Unless of course the packing is past its best or all the adjustment is used up! I have heard of people replacing the packing whilst afloat but never done it myself and you would have to know what you were doing so wouldn't advise it, and of course it depends on how good access is.
Take photo if you can and I am sure you will get some sound advice.
 

Boater Sam

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Can we be more specific as to where it is leaking? Where the shaft exits the front of the grease gland where the 2 bolts are to tighten the packing, OR is it leaking right at the back where the shaft bearing housing is screwed into the boss welded in the hull in the extreme end of the swim?
If its the first, tightening the nuts a little will probably stop it. If the latter tightening the whole bearing tube into the hull may stop it, you will need some big grips or Stilsons to do that.
 

Captain Crisp

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Hi, apologies for not being more specific. The stuffing box is all fine. It's weeping around where it exits the hull...
Thanks,
Crisp
 

Channel Sailor

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I happen to be posting at Stern Glands at the same time as you! I would guess you now know the answer to your own question. The stern tube appears to be leaking where it is bonded to hull. If it is not too far below the water line I suspect you might be able to stem the drip with some kind of temporary thick sticky oil based stuff/goo. To use other products as a temporary fix you might well have to clean it up first which might in turn increase the leak which would be risky.

I know nothing about narrow boats at all but my two penny worth would be: vibration down the shaft has loosened the stern tube, misalignment has worn the side of the stern tube, collision damage, rope or obstruction on the shaft damaged it or maybe the previous owner put some stick goo on there to stop the leak and it lasted for years but has now failed.

Maybe someone here knows about inland waterway boat engineering and how this tube is welded or GRPed into place.
 

Poignard

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You would have to remove the rearmost bearing ( the cutless bearing and its housing.), clean up everything, then seal the threads wherethe bearing ousing screws onto the sterntube and apply a bedding compound to the flange where it is attached to the hull.

I have done it on my Twister and it was a straightforward job.

I may have pictures at home but I will be in France until the weekend.
 

Poignard

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Sorry, I just notice you want a fix whilst afloat.

I can't think of one but you could haul out for a day and do it or even dry out somewhere and do it between tides.
 

Boater Sam

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Its hard to see from the pix, its bit mucky down there.
Is this a steel hull? How old? I would not advise tightening this until we can establish the construction.

This is the common steel canal boat greased gland bearing.
The black bit on the right is steel for welding into the steel hull. The brass tube holding the bronze bearing inside is screwed into this with sealing compound.
But there are other constructions. Any chance of cleaning the gunk away from yours so we can see better please?
 

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steveeasy

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Hi Captain Crisp,
The stearn tube screws on to the outer cutlass bearing carrier(I think) and I assume should be water tight. So you might be getting a leak along side it. As Poignard suggested you might need to remove it and reseal it. If its just a drip every 5 seconds id leave it until you haul out. Have you got a lot of play in the cutlass bearing ? Hows the engine mounts. If you have the original shaft as Helix did, then fair chance of wear which might cause problems.

Steveeasy
 

Captain Crisp

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You would have to remove the rearmost bearing ( the cutless bearing and its housing.), clean up everything, then seal the threads wherethe bearing ousing screws onto the sterntube and apply a bedding compound to the flange where it is attached to the hull.

I have done it on my Twister and it was a straightforward job.

I may have pictures at home but I will be in France until the weekend.


That would be great! Especially as it's also a Twister!
 

Slowboat35

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Hi, apologies for not being more specific. The stuffing box is all fine. It's weeping around where it exits the hull...
Thanks,
Crisp
You appear to be confirming that the stuffing box is not leaking, but the joint between the stern tube containing the shaft and the hull itself is leaking?

I think you need to clean all that gunk away to see what the arrangement of the stern-tube is and exactly where it is leakng. If it's welded into the hull and leaking around the welds you need to get it fixed pdq I'd say, if it's a welded-in/bolted on tube with a gland/mating face of some sort and that's leaking then some other intervention will probably be needed - tightening bolts/glands etc. I'd only be imediately concerned if it is a leak in a welded joint.
 
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Stemar

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If it's welded into the hull and leaking around the welds you need to get it fixed pdq
Yes. If a welded joint leaks immediately or after a few weeks, it's a faulty weld. If it suddenly starts after years of not leaking, corrosion is the most likely issue, and there's a risk it'll be like that tiny rust bubble in the wing of your first car that turned out to be a hole a few inches across when you cleaned it up.
 

Poignard

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That would be great! Especially as it's also a Twister!
I thought I had photos and sketches but I find they are only for the inboard bearing/stuffing box.

All is not lost however!

Vyv Cox's excellent website ( Stern glands ) gives a lot of useful information and especially this photo (which I hope he won't mind me reproducing here):

1595595527590.png

The above photo is almost identical to the cutless bearing housing I have on my Twister. After the two screws that fix the bearing housing to the hull are removed, the bronze bearing is unscrewed from the shaft anticlockwise (if looking forward).


Below is a photo of my Twister's bearing housing:

1595596254001.jpeg

You can just make out the two slotted countersunk machine screws that secure the flange of the housing to the hull.
 
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