Advice please - cutless bearing

[Jegs]

Hi,

Because the boat is being lifted to enable replacement of the shaft gaiter, I am going to purchase cutless bearings just in case. My query is whether the brass cased bearings being offered are suitable for a steel boat, your views please.

Thank you,

John G

 

[KINGFISHER 9]

No idea but great to see that you've spelled it correctly!

 

[Tranona]

Hi,

Because the boat is being lifted to enable replacement of the shaft gaiter, I am going to purchase cutless bearings just in case. My query is whether the brass cased bearings being offered are suitable for a steel boat, your views please.

Thank you,

John G

Depends on the material of your stern tube. If it is just a steel tube welded in then a phenolic shell is better, but if it is a bronze tube then either will do. You may find it is a composite bearing though. Unless you know the dimensions and type already better to wait until the boat is out.

 

[Jegs]

Thank you.

John G

 

[chinita]

No idea but great to see that you've spelled it correctly!

Is there another way to spell 'bearing'?

 

[robmcg]

I have always found the phenolic resin bearings are easier as the brass ones always seem to corrode themselves solid to anything steel. Have even had one burned off a P bracket as it just wouldn't shift!

 

[Neil_Y]

In answer to the question why introduce another metal when you don't have to? they will be OK if the steel is be protected by anodes, but you can get corrosion in the voids that will exist between the bronze and the steel when these fill with sea water.

Just to clarify the options.

For propeller shafts there are...
rubber bearings
composite bearings (these can be phenolic or polyester based these are what we work with)
composite sleeved rubber (these are often referred to as phenolic bearings the composite can be phenolic or polyester resin)
Bronze sleeved rubber


You can press the bearings in or you can slide them in by hand and bed them on epoxy. If pressed in they need to have a larger ID clearance as the ID will see some bore closure as they are pressed in.

Fitting on epoxy is ideal for steel or aluminium where there may be some corrosion as the epoxy means there will be no sea water in the voids between bearing and bearing carrier. In practice this corrosion has caused bearings to squeeze tight on shafts in some cases. Our bearings are normally made as a precise clearance on the shaft size and a clearance fit in the carrier. To remove you just heat the bearing carrier if metal or split away if it's a grp/composite tube.

We work with Exalto UK if anyone insists on having rubber.