stern gland packing

[fivebucksa]

Is it possible to replace the stern gland packing, which looks like a six inch length of waxed rope, while the boat is in the water.
I understand that a fair amount of water will come in, or is it a nono.

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[tome]

It will be several lengths of packing, usually an odd number 3 or 5 or 7. If you are brave and prepared for a fair amount of water ingress, you can replace all but the last afloat (I'm told - I've never done it afloat). Make sure you get the correct size packing - they come in imperial and metric sizes.

They should be replaced with the joins at 90 degrees to the previous packing and well greased before inserting. Don't overtighten the gland, make sure the shaft is free to rotate and be prepared to keep adjusting after each engine run for the first week or so.

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[Benbow]

I have used teflon impregnated packing from Vetus which should not be greased. It has worked very well for me. Measure it up exactly before use by wrapping it round the prop shaft and cutting at an angle to give you several 'once round' lengths. The hardest job is likely to be getting the old stuff out you will need a bent piece of stiff wire or similar.

I would dry-out to do it, but them I am a coward. If you do it on the water I suggest you have a plan B. I would certainly be very cautious, eg be 100% confident that your new pieces will fit before you scrape out the old ones!



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[tyce]

personaaly, i would not even consider doing it while it is afloat, it would be o.k. to replace the first couple of rings, but as soon as the last ring is out you will have a gusher on your hands

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[Rum_Pirate]

Can't you do it in between tides?

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[Birdseye]

How long is a piece of packing?

Deoends on the time between tides / the problems you have / your handiness etc. Took me 2 hrs on the hard.

<hr width=100% size=1>this post is a personal opinion, and you should not base your actions on it.

 

[Geordie]

IMHO, the only way to replace the packing is to uncouple the shaft from the gearbox, and remove the gland from the shaft. The need to replace packing is never urgent enough to do it while in the water. If you feel it absolutely neccessary to do it in the water, it might be possible to reduce the inflood by stuffing rag around the propshaft and into the tube, but it would IMHO still be neccessary to uncouple the shaft. If you do this, you MUST put a hose clip around the shaft to prevent it disappearing into the blue. Bear in mind the previous advice to stagger the joints and to grease well.

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[tillergirl]

Why uncouple the shaft to pack the gland?

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[rich]

I use a long self tapping screw, into the old packing then pull it out with pliers,one by one.

<hr width=100% size=1>http://www.jersey-harbours.com

 

[Plan_B]

Mine was replaced on the water - but there was a hoist close by. The fitter wound the greaser down 'to pump it full of grease' he said, and then took the packing out. He did say we'll try it, and if it start to weep we'll put the packing back in and lift the boat out.

It didn't leak at all for the hour or so it was being worked on.

Dave D

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[AndrewB]

It's quite a gusher on my boat too, when I tried a complete repack on the water. I think that is partly the result of having a deep keel with the gland some way down. When I posted about this once before, several people commented that they get no more than a trickle. As you say, replacing 3 of my 4 rings is easy enough on the water. However the bottom one eventually became compacted with long use and couldn't be removed without withdrawing the shaft.

Earlier this year I reported on changing a sea-cock while afloat - now that really was a wet experience.

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[Geordie]

My yacht is long keel deep draught and there is very little room behind the gearbox to manipulate the gland and a tool to extract the old packing while the shaft is in place and hanging head down

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[tillergirl]

Oh right. That must be tough to get at.

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[tgalea]

Hi,

I am unsure as to how much grease should be put in. On my boat i have a small grease cap which i fill in every now and then and it screws in.

How do you know when enough grease is in and if you over-grease are there are problem you could expect ?

Thanks
TYrone


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[AndrewB]

It's not critical. The normal in many boats is to screw the greaser down by hand until its it feels tight (check that isn't because the greaser is empty). This probably needs doing once each time the boat is used. Can't think of any reason why over-greasing would be a problem, except of course you don't want to screw grease it in so tight that the packing is distorted. If you don't grease enough the packing will wear sooner and you'll probably get dripping.

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[TheBoatman]

The greaser should be turned down every couple of hours during use and definately after you have turned off the engine and intend to leave the boat.

As for changing it whilst afloat, it can be done, just leave the last piece in position if your worried and put the new packing in front of the last old bit.

What you must do is cut your packing into rings first, do this by "wrapping" it around the shaft first and cut it with a Stanley knife so that you have it in "rings". Re-pack it making sure that the cuts don't line up.

As someone has pointed out don't over tighten it as you'll only increase the wear on the shaft. You need to tighten it enough to stop the drips and no more!

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[kds]

"tighten it enough to stop the drips and no more!"

Surely not - you need a drip or more per minute for cooling, I am told.
My brand new one does not drip and I am worried about it - probable too much grease in as I tended to turn the greaser whwnever I was near it while building the boat.
Ken

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[chookchaser]

To drip or not to drip? If your stern gland can be greased, this is probably a bit academic. The thing to do is to run the boat in gear for about 15 minutes after you have done the dreaded repack job, while monitoring just how hot the bearing gets. If it is not too hot to the touch, friction is unlikely to destroy anything. If it is getting hot, slack off the adjustment, add grease, and try again. Maybe it will now drip a bit, maybe it won't.
However, some stern glands do not have a greaser. These little suckers do need to drip a bit when running, and may or may not drip when stationary. Again. your main concern should be whether or not the bearing runs hot. When re-packed, they do need time and patience to adjust to a point where they may get only just warm, but never hot. My original packing was occasionally greased, hardly leaked when running, never when stationary, and lasted an amazing 29 years. When I pulled it out it wasn't too badly worn either. Whoever fitted it obviously knew how to go about it. When I repacked it, the bearing ran far too hot initially, but with some adjustment and greasing has since settled down and now does not drip at all. I am talking a sailing boat with a 50 hp diesel here - stinkies with big turbocharged engines obviously work their stern bearings harder and this advice may not be applicable.
















































































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[John_Lana]

I have changed the packing loads of times while afloat. No drama - just be sure to have the correct size of packing ready, and the rings cut to the correct length. Even if you hook out the last ring, there is rarely a scary amount of water that comes in /forums/images/icons/smile.gif

John

<hr width=100% size=1><A target="_blank" HREF=http://www.john-lana.com>http://www.john-lana.com</A> Mainly about boats, but also a bit about my other toy, my Caterham 7

 

[AndrewB]

Three or four drips a minute when running are acceptable but it need not leak at all: it should not drip when stationary.

The easiest way to test if the gland is overtight is to check whether it is getting hot in use. It should not feel more than just a little warm to the touch (take care!). My experience is that while it is easy to overtighten the gland with the compression nuts, it is hard to do so by pumping in too much grease, which simply melts and quickly flows away.

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