Propshaft/stuffing box

[Ardenfour]

New boat has vibration and shaft running out of true at the stuffing box. I got the shaft out today and it seems straight, but badly worn in the area of the gland packing. The stuffing box is conventional, with packing and floats on the end of a short rubber hose. It has a grease tube.
Can I refit it with a longer hose to move the packing to an unworn section of the shaft? It would mean extending the hose from around 150mm to 300mm.
Also, there is no cutless bearing as such at the outboard end. The shaft runs in a plastic/hard rubber sleeve in the stern tube. There is not enough clearance for a brass/ribbed rubber bearing. Any ideas what to use as a replacement? Shaft is scored quite badly here too.

 

[Tranona]

The outer bearing is likely to be a water lubricated composite such as Maritex which will be either a press fit into the tube or maybe epoxied in. What boat is it? with the stuffing box, seems like a good opportunity to replace it with a drip free seal such as a Volvo/Radice which will almost certainly run on a different part of the shaft. However if the shaft is scored in 2 places, maybe better to consider replacement. The grease does nothing for lubrication, it is there to fill the tube behind the packing to slow drips when the shaft is stationary. over greasing can reduce water cooling of the packing so hot running and wear on the shaft.

 

[Ardenfour]

Thanks. Boat is a 32' ketch. 42hp engine. Budget won't reach to new seal at this stage. I think it would need a replacement shaft too. So, anything wrong with having a longer hose to move the packing area to a clean part of the shaft?

 

[Tranona]

No - although an extra 150mm may take it above the waterline and so water may not get up to it to keep the packing cool. Make sure you get the correct hose type for the job. BTW the Volvo or Radice seals are under £100! They are 116mm long for a 30mm or 1 1/4" and that includes the part that clamps onto the stern tube. So the lip seals will run on the shaft somewhere between 75-90mm from the end of the stern tube which may be clear of the worn area. The other alternative is to fit a face seal such as a PSS which does not run on the shaft. more expensive - about the same as a new shaft.

 

[penfold]

The average packed stern gland seals on maybe 35-50mm of shaft; why do you want to move the gland 150mm?

 

[john_morris_uk]

May I add to Tranona’s reminder NOT to use ordinary hose. Stuffing box hose is very much not just ‘rubber hose’. It’s also not cheap. 300mm (12”) of it is just short of £130 from the first place I googled. Stuffing Box Hose
Save up for a new shaft and PSS seal?
The vibration/running out of true might mean the engine/shaft is misaligned?

 

[dansaskip]

Realign the engine so the shaft runs true and get a new shaft and renew the packing. It is not an area of the boat that you want to bodge.