Stuffing gland which spins with shaft leaking?

The boat I have been working on is leaking a lot of water from the shaft when the shaft is spinning. (Roberts spray 36). It has a rubber gland which is clamped to the shaft and presses against flat surface on the stern tube which does not spin.

When its not running it does not leak and when it is running its enough to get a continuous flow from the bilge pump. The stern tube has grease nipples on it close to the fitting. Is this a common type of fitting? Are they any good? Is it hard to replace it? How would I found out what type of fitting is required to fix it?

And importantly do these things fail catastrophically or gradually?

 

www.shaftsaver.com/ - sounds like you have a shaft saver.

IT might be worn out (as well as the old shaft).

Some water underway is normal/required and needed to lubricate and cool the rubber.


FF

 

Thanks Fred. It looks more like a black rubber plunger than a steel tube.