Propshaft coupling and ruddershaft bearing

[EqPierre]

Can anyone identify these items i found on my project-boat? I would like to re-use them but got no idea of the exact functioning... I guess one is a flexible shaft coupling and the other one a kind of stuffing box or bearing. On the coupling is a mark that says "CRAVEN CS77" wich i googled without results, and on the ruddershaft "bearing" is a sticker from a NZ vendor who doesn't answer my emails. Any hint would be very welcome! More about the project on eqmar.net

[Uncle Bob]

Originally Posted by EqPierre

Can anyone identify these items i found on my project-boat? I would like to re-use them but got no idea of the exact functioning... I guess one is a flexible shaft coupling and the other one a kind of stuffing box or bearing. On the coupling is a mark that says "CRAVEN CS77" wich i googled without results, and on the ruddershaft "bearing" is a sticker from a NZ vendor who doesn't answer my emails. Any hint would be very welcome! More about the project on eqmar.net

Hi, the bearing is I believe a top rudder shaft bearing complete with grease cup, the flexible coupling I cant help with, but I would ask if the blue section is metal or some sort of synthetic?

[EqPierre]

Thanks Bob. The blue section I think is aluminium. I soaked the coupling with WD40 last week so I hope I can take it appart next weekend. Do you think the rudderbearing also acts as a sealing? The lower part is welded to the hull, so as long as the rudder is in place I can't see what is inside. Planning to take out the rudder soon, to see why it is swinging only to starboard side (2 man needed to turn it the other side...) I guess they hit the rudder somewhere along its transports.

[sailah]

The blue thing looks like a drive saver of some type. Agree about rudder bearing, they dont typically seal though.

[Mike Banks]

The bottom rudder shaft bearing is traditionally Lignum Vitae but slippery elm will do as well, but these days they are usually some sort of nylon-polyethene or polypropene compound. Even hard rubber/plastic or Teflon might be found.

Neither bearing is sealed--the bottom one is seawater lubricated, the top one is usually bronze and is grease lubricated, in my case using white water pump grease. There is always some moisture which will reach the top rudder bearing through a rudder shaft tube--condensation will see to that even if wave action does not.

[captlloyd]

Yes that is a rudder shaft bearing, a massive one. The other is a flex coupling, reduces shaft vibrations plus can isolate your prop shaft from a electrical standpoint.