Stern gland - bearing?

[vyv_cox]

I've never been quite clear what the greaser is for. I've assumed that it is to completely stop dripping when the engine is not running but, when I think about it, the grease is introduced aft of the packing and will therefore fill the stern tube and the cutlass (cutless?) bearing eventually. However, on my boat, it could be observed extruding from the gland. So, what prevents it from going into the stern tube where it is going to impede/block the flow of water to lubricate/cool the gland?

Nothing, as far as I can see. I finally gave up on my packed stern gland, working perfectly but remembering to grease it and carrying the grease around was a nuisance. When I took everything apart the stern tube was nearly full of grease but the packing didn't seem to have any in it at all. I doubt whether it had contributed anything worthwhile for all those years.

I have seen one that had a lantern ring-type arrangement to ensure that grease got to the packing but this seems so rare that I suspect it was a one-off installed by a previous owner.

 

[Tranona]

Some of the older sterngear like my Stuart Turner had a white metal bearing in the forward end of the tube - that was what the grease was for. Can't see any point in grease otherwise as the water cooled packing makes the (imperfect) seal.

Better to chuck the whole lot away and fit a modern seal, preferably a Volvo seal, although it will not fit all stern tubes, but there are other good alternatives on the market.

 

[ghostlymoron]

Some of the older sterngear like my Stuart Turner had a white metal bearing in the forward end of the tube - that was what the grease was for. Can't see any point in grease otherwise as the water cooled packing makes the (imperfect) seal.

Better to chuck the whole lot away and fit a modern seal, preferably a Volvo seal, although it will not fit all stern tubes, but there are other good alternatives on the market.

I have a drying mooring so I would have to 'burp' a modern seal every tide - so not really an option?

 

[vyv_cox]

I have a drying mooring so I would have to 'burp' a modern seal every tide - so not really an option?

Can't speak for a Volvo seal but a PSS has a vent tube, simply a length of hose led to a high point above water level in the engine compartment (or above if necessary). This prevents airlocks and the need for burping.

 

[Tranona]

I have a drying mooring so I would have to 'burp' a modern seal every tide - so not really an option?

Yes, burping is necessary on a Volvo, but not on the more sophisticated lip seal units such as a Tides. However, depending on your stern tube end fitting you could use the grease hole to put a tail in to take a vent tube.