Stern gland questions...

Your sterngland may be a water lubricated version but will still need packing and grease applied,then tightened until the drip if any reaches an acceptable period/quantity - after runing the engine in gear .Most packing nowadays is ptfe impregnated so will always be lubricated to some extent,and fitting a greaser may not be required. The job of repacking is easily done between tides,get all the kit ready,not forgetting the Stanley knife!

ianat182
 
VO5 said:
Two daft question no one has asked...:eek:

(a) In order to select the proper size of packing material for a stuffing box, is it possible to expose the existing packing while afloat ?

(b) Is it possible to replace the packing while afloat without sinking the boat ?

Has anybody tried these daft ideas ?:o
Click to expand...

If you have the type of gland shown in the pic you can undo the 2 adjustment nuts and slide the compression plate towards the engine and very little or no water will come in, the packing rings will stay tight and form a seal. If you were feeling brave you could probably even remove 1 of the rings to measure it bearing in mind it will be compressed and worn. I have heard of people removing the old rings whilst afloat and being ready with a bucket and new rings cut to size. Some do it but leave one old ring in place. But unless you know how many rings you have how do you know when you are down to the last one?
 
Iain C said:
Many thanks guys.

I will give the whole lot a squirt with some WD40 to penetrate the threads, and have a go at snugging it up on the adjustment, and "bleeding" any air out the grease system. !
Click to expand...


WD 40 is the totally wrong product....It IS NOT a release oil.... Get Plus Gas in Halfords etc and you might do the job.


Wrap the studs with rag and then soak the rag with plus gas and leave for 24 hours min. You may have to use a die nut to clean up the exposed thread.
 
Andrew_Fanner said:
Facing a stern gland adjustment on Friday. First time I have ever had a traditional packing style gland, still surprised that there is no greaser. As far as I can see its back off the locknut, tighten the packing nut until the drips stop, or at least drop to 1 a minute or so and then wang up the locknut again. Of course, with my v drives, naturally, the whole thing is under the primary gearbox!
Click to expand...

Many stern glands do not use grease, grease can cause more problems than it cures as it is a poor conductor of heat and it can end up blocking water channels in stern tube bearings resulting in excessive heat and accelerated wear. Water is a great lubricant and coolant.

For freeing seized parts ACF-50 is excellent as it dissolves the products of corrossion.
 
Last edited:
VO5 said:
Two daft question no one has asked...:eek:

(a) In order to select the proper size of packing material for a stuffing box, is it possible to expose the existing packing while afloat ?

(b) Is it possible to replace the packing while afloat without sinking the boat ?

Has anybody tried these daft ideas ?:o
Click to expand...

To add a bit more to Spyro's advice - take a few drills on board to use as gauges to measure the gap into which the packing fits. It will probably be either 3/16", 1/4" and 5/16"
 
Neil_Y said:
Many stern glands do not use grease, grease can cause more problems than it cures as it is a poor conductor of heat and it can end up blocking water channels in stern tube bearings resulting in excessive heat and accelerated wear. Water is a great lubricant and coolant.
Click to expand...

I think you are absolutely right about that. When I bought my boat I fitted a hefty screw-down grease pump and used it often. (My progress around the coasts of UK and France must be marked by trail of Morris's K99 sterntube grease.)

As a result of following the sensible advice in this thread, this year I have used a fraction of the grease used in previous years and I now find the stern gland runs much cooler and there is only an occasional drop of water coming through the gland instead of the filthy slurry of emulsified grease I used to get.

If I had bothered to think about it before I should have realised that the reason so many older boats were originally fitted with small capacity Stauffer grease cups is that very little greasing is needed in a low speed, low power installation.
 
VO5 said:
Two daft question no one has asked...:eek:

(a) In order to select the proper size of packing material for a stuffing box, is it possible to expose the existing packing while afloat ?

put plenty of grease down the shaft via the grease cup.
Remove the lock nuts and other nuts
knock the collar up the shaft
measure the distance from the shaft to bit where the colar slides in , this gives you the packing size

(b) Is it possible to replace the packing while afloat without sinking the boat ?

Yes many times,we had a twin screw MY for 20 years.

nearly ALWAYS replace packing afloat. can only think onf one occasion where it was done while slipped, & that was when the shafts were changed. Draft at stuffing box was ca 2 feet

Has anybody tried these daft ideas ?:o
Click to expand...

The pictures show what you see looking up the shaft, & the second a spiral of packing (removed) that not been cut in rings.This had been installed by a boat yard in the midlands on a friends canal boat. Incidently the grease method was used here as well. Ptfe packing was used, although I use to install graphite packing, but it is now thought the graphite leads to shaft wear.

my tips

use a thin screw with a good head , so you can grip it to remove old packing

If you cant get in there to see you have all the packing is out, & nobody has a mirror...... A phone camera does a good job in a tight space as below
 
Last edited:
Spyro said:
If you have the type of gland shown in the pic you can undo the 2 adjustment nuts and slide the compression plate towards the engine and very little or no water will come in, the packing rings will stay tight and form a seal. If you were feeling brave you could probably even remove 1 of the rings to measure it bearing in mind it will be compressed and worn. I have heard of people removing the old rings whilst afloat and being ready with a bucket and new rings cut to size. Some do it but leave one old ring in place. But unless you know how many rings you have how do you know when you are down to the last one?
Click to expand...

No, my stuffing box is different and has the two nuts and thread and complete with nipple, grease line and greaser.

I have had the idea of perhaps diving under the hull and stuffing plasticine temporarily at the exit to prevent or limit the ingress of water while changing the packing and then diving again and removing it when the job is complete...just an idea..:eek:
 
To find the size of packing required subtract the shaft diameter from the diameter of the gland follower and divide by 2.
I have repacked a gland when afloat but not recommended,try leaving one turn of packing in situ, it might help.
 
VO5 said:
I would like to hear from anyone who has removed all of them while still afloat, to find out what really happens..:eek:
Click to expand...

see my earlier post..

what happened

nothing!!!


Think about it

how big is the gap between the shaft and the bearing, even with no grease it is only a sub millimetre size, so can only let through a dribble.

I am afraid too many people think of a scene out of das boot. Think what sort of spray you would get by connecting a gardern hose to a water butt. Not much, well the worst case on the average boat would be less than a third of that.

to change the packing while leaving one behind defeats the object of the exercise.
 
Thanks for your reply above.

Now that it is explained, it makes perfect sense.

Obviously that explains why there is a steady small drip on worn packings and not a large one when the prop shaft is at rest, irrespective of how worn the gland packing might be.

Now here is another angle, I hope it is not off topic...

An engine with a large heavy flywheel has a propensity to shudder at very low revs and when idling, I am told, even if the engine mounts are OK.

This engine shuddering causes the shaft to vibrate more than normal I should imagine.

At higher revs this shuddering disappears.

Question : Is there some way of reducing the shuddering at the shaft coupling and hence the wear on the packing ?

Do flexible joints exist that in some way might reduce or eliminate this problem altogether so that the shaft does not vibrate excessively ?

Any information on this would be very welcome. Thanks.
 
john_morris_uk said:
May I second that - the rubber pipe is a special pipe made for stern glands. Please don't replace it with something that is the same size and looks as though 'it will do'.
Click to expand...

My grandad once replaced his with a slice of welly boot folded in half, and some *big* jubilee clips.

And then set off across the Atlantic.

He was a good sailor on the sticks and string front, but my Dad always described him as a mechanical disaster area.

Pete
 
VO5 said:
Thanks for your reply above.

Now that it is explained, it makes perfect sense.

Obviously that explains why there is a steady small drip on worn packings and not a large one when the prop shaft is at rest, irrespective of how worn the gland packing might be.

Now here is another angle, I hope it is not off topic...

An engine with a large heavy flywheel has a propensity to shudder at very low revs and when idling, I am told, even if the engine mounts are OK.

This engine shuddering causes the shaft to vibrate more than normal I should imagine.

At higher revs this shuddering disappears.

Question : Is there some way of reducing the shuddering at the shaft coupling and hence the wear on the packing ?

Do flexible joints exist that in some way might reduce or eliminate this problem altogether so that the shaft does not vibrate excessively ?

Any information on this would be very welcome. Thanks.
Click to expand...

They do but you need space to install the answer,

see


http://www.halyard.eu.com/Products/aquadrive_range.html


an excellent product, we have a short section shaft to drive our hydraulic pump for the bowthrust, you will need one with a trust bearing. there are other partial soloutions, but this is best.

Their pages well explain the installation requirements.

I have no connection to the firm other than a happy customer, for this and exhaust products.
 
You must log in or register to reply here.

Share this page

Top