Gland packing

[Roxylass]

Boat back in the water this week 

noticed a small drip not much of a drip but again don’t want a drip at all

engine in question Lister SR2

is it a case of taking the nut of each side of the prop shaft and pull the collar back 

remove packing and renew 

also is the graphite packing the best to use 

quite sure my prop shaft is an inch in diameter 

[David Mack]

You probably just need to tighten the packer up a touch. Give a turn on the greaser then turn each nut one flat clockwise (1/6 of a turn). Check that in neutral the shaft still turns freely (if your gearbox allows - some don't) and you should be fine. If it is still dripping, tighten up another flat on each nut. 

[robtheplod]

Did I hear its suppose to drip occasionally?  no drip at all is a sign its too tight? 

Edited April 20, 2022 by robtheplod

[Roxylass]

I wouldn’t think so

[TheBiscuits]

14 minutes ago, robtheplod said:

Did I hear its suppose to drip occasionally?  no drip at all is a sign its too tight? 

 

Only from someone who can't correctly pack a stern gland.

 

If you can rotate the propshaft by hand and the gland doesn't get hot when running, it's not too tight.

[Tony Brooks]

22 minutes ago, David Mack said:

You probably just need to tighten the packer up a touch. Give a turn on the greaser then turn each nut one flat clockwise (1/6 of a turn). Check that in neutral the shaft still turns freely (if your gearbox allows - some don't) and you should be fine. If it is still dripping, tighten up another flat on each nut. 

 

Almost certainly the box on an SR2 will be a LH150 and you cant turn it in neutral with the engine off unless you jack the ahead clutch out of engagement.

[OldGoat]

In my boating days (too long ago to admit), the perceived wisdom from them-as-knows - that the occasional drip of water was correct and indicated that the lubrication system was working correctly (for the more senior boater - as in  the Erasmic shaving advert: - not too little, not too much, but just right....)

The logic is that there's a wee bit of water coming through the prop-shaft setup to indicate that there's enough fluid to cool the shaft overall. By having a well designed catchment area it's easy to mop up any water (I use baby nappies) to keep the bilge dry, but also so indicate that the prop shaft has some form of lubricant (water / grease/ emulsified grease). Works for me some 30+ years later.....

 

 

[Rincewind]

1 hour ago, robtheplod said:

Did I hear its suppose to drip occasionally?  no drip at all is a sign its too tight? 

You are correct.  Glands with stuffing boxes are designed to drip, the water not only helps cool the assembly it keeps the packing moist and disperses heat.  Tightening the gland to the point where water is prevented from dripping will lead to the packing drying out which in turn will lead to greater friction between the (now hard) packing and the rotating shaft. That friction will wear away both the shaft and the packing leaving grooves in the shaft and shredding the packing.  This leads to even more increased dripping and then the gland is tightened again and... so on and so on.

New prop shaft please...

 

The trick is regulating the drip to an acceptable level

 

You should grease the stuffing box each day when travelling. Do it after you have stopped for the day and the grease will act as a stopper overnight.

 

I have a hard plastic container under my stern gland to catch the water and my auto bilge pump is situated in the container.  My engine bay is completely dry...always!

Edited April 20, 2022 by Rincewind

[Roxylass]

Hi Tony 

the gear box on this SR2 LM 100

[Bee]

We have to leave the boat unattended for quite long periods, It does drip just a wee bit when the shaft is turning but when we leave it I just give it a good dose of grease and tighten the nuts just a bit less than 1/4 turn, That stops it dripping. When we get back I give it more grease and slacken the nuts a tiny bit. Too much tightening of the nuts will harden up the stuffing and risk wearing the shaft - hard to believe but it really will. A few drips is wuite OK, I hve an old baked bean tin under mine and half a tin of water now and again is no worry.

[robtheplod]

On 20/04/2022 at 21:25, Bee said:

We have to leave the boat unattended for quite long periods, It does drip just a wee bit when the shaft is turning but when we leave it I just give it a good dose of grease and tighten the nuts just a bit less than 1/4 turn, That stops it dripping. When we get back I give it more grease and slacken the nuts a tiny bit. Too much tightening of the nuts will harden up the stuffing and risk wearing the shaft - hard to believe but it really will. A few drips is wuite OK, I hve an old baked bean tin under mine and half a tin of water now and again is no worry.

When we leave ours it doesn't drip at all, only when after a cruise does it drip again (until we turn the greaser).....  good idea re baked bean tin!

[Laurie Booth]

17 hours ago, robtheplod said:

When we leave ours it doesn't drip at all, only when after a cruise does it drip again (until we turn the greaser).....  good idea re baked bean tin!

Mine is the same, I use a washing up bowl to collect the water with the bilge pump in the bowl.