water lubricated bearing

ironmaiden

ironmaiden

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on Tuesday I orderd a shaft, water lubricated bearing and coupling from T Norris, they all came on friday, now thats a good company with good service, no connection just well impressed.....any ways.....
the bearing is composit cos it's going into a steel tube, all those I've used in the past have had a hard resin shell with internal rubber for the bearing this one hasn't it's just rubber, and all quite flexible.
So, have any of you lot used this type before and do they stay in place in the tube ok using the normall couple of grub screws on each side of the stern tube. I have visions of it just spinning around with the shaft untill it rips its self apart.

regards rachel
 
I think you will find that this type a fairly standard on Benes. We have one on ours. It is secured by two nylon set screws going into dimples on the cutless. It ts unlikely to spin (even without the screws) as the friction betwen the bearing and the tube is much greater than between the shaft and bearing.
 
vyv_cox said:
It's new to me. Difficult to imagine how to install it and I share your concerns about retaining it. Try asking someone at T.Norris.
Click to expand...

spoke to norris's and they say they dont supply the phenolic shelled any more as they swell in the water ?
they assure me that these are better...but i dont know!
 
Why not use a bronze shell one. Had steel boats for 25yrs and never had a prob. removing them.Smear all over with silicon grease and it will come out OK.
 
rubber cutlass bearings

they are common on french boats. they are more difficult to install. really need a mandrell.but a doddle to remove, but as another thread drift. once had a phenolic bearing burnt out by a stray fishing line going up the tube. 36ft pushy cat tug.no spares .machined one out of takamata wood . lasted 15months of daily usage , not very green as we pumped in a lot of grease.I prefer bronze casing with rubber even though its a pain to chisel out.now does any one know where to get takamata wood.challenge for the day?
 
ironmaiden said:
spoke to norris's and they say they dont supply the phenolic shelled any more as they swell in the water ?
they assure me that these are better...but i dont know!
Click to expand...

Phenolic ones are known to swell and the clearance between the rubber and shaft is normally greater when new to allow for this. The first time I fitted one I was quite alarmed at the rattling shaft but within a week on the mooring the clearance had gone. I didn't know that suppliers were concerned at this though. For many years now I have only used brass tubes. It sounds as though the all-rubber ones are well known (although not to me) and should be OK.
 
The old Stuart Turner type of the 60's were all rubber. I changed one 2 years ago though the replacement now has a phenolic shell. The old one appeared to have been fixed in with some kind of adhesive, possibly rubber solution of the type well known to cyclists. It was a bu**er to remove and had lasted nearly 40 years!

John
 
Phenolics

Plain rubber ones are fairly common, but I have to say that Phenolics is a general term for a wide variety of materials. As it is a composite the manufactirung process and ingredients greatly effect the performance in terms of water absorption.

Fully phenolic (no rubber) bearings are used on a wide variety of craft with shaft sizes from 1" to over 22". Clearances are known and a clearance chart calculator is used to determine ID and OD this is one
http://www.h4marine.com/Downloads/Maritex AQUARIUS General Calculator REV 20090222.xls

Phenolic bearings can also be installed as a clearance fit in the carrier on a bed of epoxy, allowing confirmation that the carrier is aligned with the shaft line. Rubber as an interference fit makes this far more difficult.
 
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