Stern Gland

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BrianLynch

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I have just dismantled and repacked the stern gland on my Trident 24 for the first time. I am a competent land based engineer but know little about the marine element ! Learning rapidly !! When I used the stern gland greaser to refill the stern tube with grease, I noticed that the grease was coming out through the hull onto my prop shaft. Is this normal or do I have a problem with the carrier bearing in the hull ? Any advice would be greatefully accepted as I do not want to crane in my 'baby' and discover that I have a terminal problem !!! (Boat is currently on the hard).
 
No offence....

Did you spiral the packing or cut to lengths and offset each gap. When you first look and have a long length of packing in your hand it looks like you should just wrap around the shaft in one continual coil which is bad! Luckily I was told how to do it properly by the marine engineer I bought it off.

Also, did you cover the packing with grease before you fitted, like rolling split bearings in grease before assembly. After a couple of runs you will also find the need for a turn on the packing bolt as the new packing will bed in and shrink a little.

When running I give about 3 squirts every month. Weekend sailing only, more on holiday when the boat is getting more use. Keeps the drips away for me. You are not trying to fill the tube by the way, just lubricate the packing the material.

Not trying to teach you to suck eggs here, just that you said it was new to you. Just thought I would mention it before the crane arrives......
 
I dont fully understand your description but gather that the grease is coming out of the gland, between the bearing and the shaft?

It sounds as if the bearing in the stern gland is badly worn, in which case you need a new gland bearing. That may mean a new gland assembly, unless you can get a bearing for your gland.

Ian
 
No, I agree with Andy, it is quite normal, add lots of grease and it will run down the shaft and appear at the cutlass bearing too.

All the boats I have been involved with have shown grease on the shaft when you pump into the nipple. It can be a good indication that the greaser is actually working.
 
I would go with this as there's nothing to stop grease emerging from the back of the sterntube if over-liberally applied. Mine certainly has no "stern gland" between the end of the stern tube and the cutless bearing. The only possible problem I can see with grease coming out of the stern tube is that it might block the cutless bearing channels which need to be clear for water lubrication.
 
May I hi-jack, or at least extend, this question please? I have repacked my inboard stern gland, having replaced the propshaft. When I pushed the new shaft in, from the inboard end of the stern tube, it pushed out a whole load of grease. First question is, should I put an extra amount of grease through the greaser/stuffing box to replace it? Second question, my stern bearing is not the usual cutless bearing, it appears to be a plain metal bearing with no facility for lubrication, does it need lubrication? It has certainly caused no problems so far. There was little movement in the old shaft and no movement in the new one.
 
Some types are sea water lubricated and do not have a grease fitting. The seawater makes its way up from the cutlass through the tube, is absorbed by the packing and then emerges as a drip from the stuffing nut. Mine has the added seawater line at the stuffing nut connected to a nearby through-hull for a definite water source.
 
Gordon is spot on here.

We get to replace cutless bearings that have failed due to grease.

Grease is a poor conductor of heat and not good for a bearing designed to run on a water film with water conducting the heat away. Grease will cause it to run hot and fail prematurely.

Many stern glands work very well with no grease, I would think they work better and run cooler.
 
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