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Stern tube packing


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#1 markh

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Posted 16 October 2008 - 06:43 PM

now then, we've got a bit of a leaky stern tube, I suspect the packing is non existant and needs re-packing, but she's not going to be back out of the water till next feb.  Inboard side, I thought oabout drilling and tapping the stern tube and sticking a ggrease nipple on so I can pack it with the grease gu.

good idea/bad idea?  perils and pitfalls?

#2 Barry McCrindle

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Posted 16 October 2008 - 06:52 PM

I take it it's leaking quite badly?
If its just dripping in even after gland is nipped right up, would say it's just dried up.
I've done it before by winding the gland as hard as it will go and then undoing it and putting an extra couple of turns of packing in, be prepared to get wet.
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#3 markh

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Posted 16 October 2008 - 08:08 PM

wound it up tight as we can, 2to3 drips per second at last count

good packing material for shoving a bit more in??

#4 Barry McCrindle

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Posted 16 October 2008 - 08:20 PM

Either PTFE packing or graphite packing, PTFE is the best to use as it reduces wear on the shaft but is the more expensive option, maybe go for the graphite now and when she's out of the water rip the old stuff out and replace it all with PTFE
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#5 markh

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Posted 16 October 2008 - 08:57 PM

bit nervous about how wet though!

up until a fortnight ago the tube was encased in concrete right up to the gland - http://ebgb.net/misc/the-hole.jpg

you can just make it out in the bottom corner, as my oppo is knocking out the crap, so... you reckon whip the end of and get some fresh packing in sharpish rather than a grease nipple?

never seen so much 'ballast' in a boat, reckon we must have moved getting on for 6 or 7 tons so far, this bit was concrete that had been poured ontop of an assortment of scrap iron, probably still 3 tons or more scattered about the place, surely we shouldn't need that much ballast, bugger thats another question!

#6 Barry McCrindle

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Posted 16 October 2008 - 09:05 PM

Slacken it off but not right off if it is really heaving in, maybe think about it again.
Also just in the event have a salvage pump handy.
The grease nipple is a possibility as well, as a lot of the packed shafts I have sailed with have an auto greaser system that puts a couple of shits of grease in every 6 hours or so.
Just depends on the type of metal of stern shaft casing.
Either that if the boat is still under her own steam put her on a beach for a tide then no probs
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#7 Jammy

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Posted 16 October 2008 - 09:12 PM

have your bilge pump at the ready mark you can loosen the gland off and it shouldnt flood but put some packing in or you will wear out the bearing whether they are cutlass, bronze or white metal it is better to do something before it gets too bad cutlass bearing are not to expensive but white metal are if they are worn i would replacethem sooner rahter than later so there is no wear on the shaft

when you are out the water next year put a long pinch bar in below the shaft and try to move it up and down and hope you cant other wise you need new stern bearings

for new packing any maarine engineer or chandlery should be able to get the right material i am not a fan of the graphite stuff as if it dries out then it can vause wear and heat on the shaft

#8 markh

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Posted 16 October 2008 - 09:22 PM

luckily just a cutlass bearing, which was in fair condition when we dried her out a while back.  will maybe give it a go at low tide in the marina when she's almost sat on the bottom already.... just in case

#9 Jammy

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Posted 16 October 2008 - 10:40 PM

as long as you have a decent depth of well in your bilge you wont go to the bottom slacken off the nuts and gently tap the gland out if it is sticky to move it wont or shouldnt fly out of place

#10 markh

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Posted 16 October 2008 - 11:12 PM

tap gently!  ;D

I'm betting it's going to be one of those Haynes manuals moments, where 'tap gently to separate' translates to 'mash the thing within an inch of its life'

plenty of bilge space, its just that whole alien concept of being in a boat and watching water coming, its just plain wrong!

#11 Barry McCrindle

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Posted 16 October 2008 - 11:14 PM

Tap gently coming from Jammy means hit it till it breaks, sadly Jammy suffers from sexy finger, everything he touches he f**ks
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#12 Adoration II

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Posted 17 October 2008 - 07:49 AM

tat male and female barry c he nos a bit about tern tube packing   :;D
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#13 restlesswave

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Posted 17 October 2008 - 09:13 AM

another wee tip mark-before you slacken anything have your packing cut to size (well youll have to slacken it first to determine the exact packing size you need-pull out a ring of packing and measure its thickness) so anyway you have the right size of packing go down to the tailshaft and wrap your packing round it tightly and then run a sharp knife squarely fore and aft across the packing coiled on the shaft-that`ll mark it to the exact length uncoil and cut the ends squarely. when you put the rings in stagger the gaps. i would be more inclined to beach her, replace the lot with fresh packing and it`ll give you plenty of time for messing about-after that you`ll have no bother tackling it when it`s floating.
    as barry says ptfe is the job but graphite is good enough also (graphite in mine) also theoretically a packing gland is supposed to be loose enough to drip very slowly-and thats why a lot of the older ones had greasers/cups etc when you came in you gave the grease cup a wee turn and it stopped the drip. but with modern packing (esp ptfe) you can nip it up carefully till the drip just stops. the packing should be slack enough that on your size of boat you should be fit to turn the prop by hand via the coupling (or even with a wee bar/big screw driver as a lever) before you pack it get a feel for how the shaft turns so after you pack it you can check it still feels the same way so its not too tight-it`s amazing how quickly too tight a packing can wear esp a bronze shaft. obviously the boat needs to be floating when you are turning the shaft as the boat aground is mis-shapen and it may make the shaft feel tight.
bend it,and if you can`t bend it,break it.

#14 markh

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Posted 17 October 2008 - 10:17 AM

the shaft is sloppy as owt just now.  even the bairn can turn it.  lost count of the number of times I've stood on it whilst down there and its turned and pitched me off.  Going to go for the ptfe/teflon stuff, stainless shaft, and graphite and stainless are not the best bed fellows in galvanic terms, divent fancy buying a new shaft in a year or 2!

my guess is that the packing had settled considerably all the years she sat on the caley and did nowt, and then hammering down here in one go finished it off

Every boat I've had has had a grease nipple on the tube or fixed greaser, but not this one

gonna give it a go this weekend, maybe need to buy a few extra buckets first (and a 45' foot sponge)!

#15 quiet waters

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Posted 17 October 2008 - 10:31 AM

they sell spongers in 6ft lengths in fraserburgh, theres a picture of one on this site, long as you don'yt get a woman to unpack it for you, you'll never get it packed again!!!!
And their teeth will be blunted like lions and they will be cast away on whirlwinds and such!!!!

#16 restlesswave

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Posted 17 October 2008 - 10:52 AM

droll qw-10 outta 10.
bend it,and if you can`t bend it,break it.

#17 markh

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Posted 18 October 2008 - 07:42 PM

thought feck it, (ok bottled it!) and just nipped it up a bit, seems to have stopped the drip for now. Off out fishing next week end so see what its like when she's had a days running then maybe do it 'proper'



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