Cutlass bearing

[Roxylass]

When taking the prop for winter storage noticed a small amount of play 

on the prop shaft fits onto lister lm 100 manual gearbox 

read a thread on here that says the prop shaft for the lm 100 diameter is 1.375in

are these bearings easy to strip and fit never had to tackle something like this before 

rather have it done sooner than later 

also a merry Christmas to you and yours 

[BEngo]

I assume you were taking the whole boat for winter storage, not just the prop?.

 

You will need to measure your prop shaft as there is no guarantee that the recommended size had actually been fitted.  Most modern boats seem to use 1 1/2 in shafts.  A big adjustable spanner and  a tape will do to measure diameter if you don't have a caliper.

 

Are you sure it is the cutless bearing? Is the shaft play laterally  and vertically or fore and aft.  Does the stuffing box of stern tube gland leak much?

 

Removal of the bearing is not difficult, once you have found how it is retained, but you will need to be out of the water. 

When you replace it make sure that the lubricating water inlets are clear.

 

N

[Tony Brooks]

I very much doubt its a Cutless bearing unless you could see the fluted rubber  around the shaft. You usually get a little lft in a Cutless bearing as the rubber compresses.

 

If the shaft assembly is contemporary to the boat its likely to be a plain metal bearing and at the probable age I would expect some play/lift in the bearing but as long as the stern gland is not causing problems I expect a pain metal bearing will go on for years.

 

I would not attempt a change of a plain bearing myself.

[BEngo]

34 minutes ago, Tony Brooks said:

I very much doubt its a Cutless bearing unless you could see the fluted rubber  around the shaft. You usually get a little lft 

 

I would not attempt a change of a plain bearing myself.

Tony, would you elaborate on why this is please.?

 

 The plain bearing itself commonly  screws into a threaded boss welded into the sternpost and the stuffing box usually  screws onto the front of the bearing, so it does not seem difficult to do and should not affect alignment.  On a slip or dock of course.

 

The state of the tail shaft  is a risk  but can be investigated without docking, of plan to change it anyway.

 

N

 

[Tony Brooks]

12 minutes ago, BEngo said:

Tony, would you elaborate on why this is please.?

 

 The plain bearing itself commonly  screws into a threaded boss welded into the sternpost and the stuffing box usually  screws onto the front of the bearing, so it does not seem difficult to do and should not affect alignment.  On a slip or dock of course.

 

The state of the tail shaft  is a risk  but can be investigated without docking, of plan to change it anyway.

 

N

 

 

Mainly because I have not done one and I would want to have done many to be reasonably confident I knew just what to expect from a whole range of boats.

 

I have done Cutless bearings in P brackets and in outboard bearing housings on wooden boats that unscrew from the stern tube. Getting a Cutless bearing pulled into a P racket with the shaft in position can be a right pig and he shafts had shrunk on half couplings so not easy to removed and refit properly. The outboard bearing housings were far easier because the bearing can be pressed in and out.

 

I do not have access to a press.

 

It seems to me that on some narrowboats what i would call the outboard bearing housing is  welded to the hull rather than unscrewed from the  shaft. I accept the bearing might be in the back of the stern tube that is screwed into the boss on the back of the boat but I don't know and don't know how the plain bearings are fitted.

 

I understand some shaft bearings are white metal so another potential problem area.

 

Almost certainly the boat will need to be out of the water and unless ashore for winter storage that's an expense that might grow unless the boat goes back in PDQ so I'd rather leave the bearing job to the yard.

 

So in my case lack of equipment and sufficient relevant experience.

 

I also am far from sure about how accurate @Roxylass's description ad identification is. I am not even sure what type of boat it is or of the OP's experience. To many unknowns for me to be comfortable saying its a DIY job even though in some or a lot of cases it might be.

[Tracy D'arth]

As I read the OP, he is talking about the thrust bearing in the gearbox, not a stern shaft bearing, but it confuses me why the shaft size is referred to if this is the case.

[Tony Brooks]

1 minute ago, Tracy D'arth said:

As I read the OP, he is talking about the thrust bearing in the gearbox, not a stern shaft bearing, but it confuses me why the shaft size is referred to if this is the case.

You may well be correct, not a very understandable question. But no gearbox ever used a Cutless output bearing so perhaps the OP will come back and explain more, I have never heard about taking a prop off for winter storage so who knows.

[Sea Dog]

1 hour ago, Tony Brooks said:

You may well be correct, not a very understandable question. But no gearbox ever used a Cutless output bearing so perhaps the OP will come back and explain more, I have never heard about taking a prop off for winter storage so who knows.

Hmm, curious. I confess I immediately thought it referred to a water lubricated rubber covered bearing where the shaft enters the hull within touching distance of the prop. It'd certainly be the most likely bearing to notice whilst taking the prop off, wouldn't it.

[Roxylass]

The boat in question is a q 18 ft cheverton on a hard standing 

when I took the prop off with a prop puller

i noticed that there was a tiny bit play on the shaft when i gather there shouldn’t be any 

the engine in question is a lister sr2 with the lm 100 manual gearbox 

the packing gland was stripped two years ago and new packing in the correct procedure no water dripping 

from the gland at all 

as I said only slightest movement up and down side to side 

[Roxylass]

Sorry took the propeller off prop shaft still in position in the boat 

[Tracy D'arth]

So it is a stern shaft bearing.

 

If it is a rubber cushioned cutlass a little lateral play is allowable, if its a greased sleeve bearing less so.

[Roxylass]

I will try and get a wee video over the weekend easier for me 

than trying to type something out 

[Tony Brooks]

15 minutes ago, Tracy D'arth said:

So it is a stern shaft bearing.

 

If it is a rubber cushioned cutlass a little lateral play is allowable, if its a greased sleeve bearing less so.

Agreed.

 

If it is a Cutless bearing  then if the OP really wants to replace it I would proceed as follows.

 

Remove prop

 

Undo the two fixings on on the back of the keel so the  bearing housing can be unscrewed. If he is lucky it will be two bolts or screws into the back of the keel that will cm out but being a GRP boat  the nuts may be glassed onto the back of the keel void. If so the glass may need chiselling off and when gone re-glassed in a similar manner.

 

Undo housing and pull off the the shaft,

 

If its a Cutless bearing it may be retained in the housing by one or two (Alan) screws in the side of the housing. These need to come out before trying to push the bearing out.

 

Push bearing back in and drill through the screw holes to from dimples for the screws to secure the bearing.

 

Reassemble is the reverse order

 

 

Edited December 30, 2020 by Tony Brooks

[Steve56]

On 31/12/2020 at 01:54, Roxylass said:

The boat in question is a q 18 ft cheverton on a hard standing 

when I took the prop off with a prop puller

i noticed that there was a tiny bit play on the shaft when i gather there shouldn’t be any 

the engine in question is a lister sr2 with the lm 100 manual gearbox 

the packing gland was stripped two years ago and new packing in the correct procedure no water dripping 

from the gland at all 

as I said only slightest movement up and down side to side 

I would be very surprised to find a cutlass bearing in a Cheverton. It'll more than likely be a brass or something similar bearing.

[Tony Brooks]

Thinking about it the stern bearing housings with Cutless bearings on our GRP and wooden cruisers were longer than that one so @Steve56 says probably a plain metal bearing.

[Roxylass]

Managed to get the bush off solid brass 

one inch by one and a half inch four and a half inches long 

[Steve56]

3 minutes ago, Roxylass said:

Managed to get the bush off solid brass 

one inch by one and a half inch four and a half inches long 

That's what I thought you would find buried away in the tube.

 

[Roxylass]

Any idea where I could pick one up Steve 

does it actually look in bad shape 

[Tony Brooks]

1 hour ago, Roxylass said:

Any idea where I could pick one up Steve 

does it actually look in bad shape 

1. Not Steve but no. Possibly try Norris of isleworh

2. I  think we would need a much better look at the bore to asses how oval it has become. I see you have three grease grooves so if each groove is more or less the same depth with no sign of taper along its length then I would say its probably OK and if you had greased it before testing for play it would have been OK

[Steve56]

51 minutes ago, Tony Brooks said:

1. Not Steve but no. Possibly try Norris of isleworh

2. I  think we would need a much better look at the bore to asses how oval it has become. I see you have three grease grooves so if each groove is more or less the same depth with no sign of taper along its length then I would say its probably OK and if you had greased it before testing for play it would have been OK

I don't  really know of anywhere, but as Tony Brooks says T.J. Norris would be a good starting place. As for wear it is not really that easy to tell just by looking at it. It would need measuring to check. Really the simple way is to slide it on to a good section of shaft and see how it feels.

[BEngo]

Typically a stainless  tail shaft will wear faster than the bearing, because the grit etc. in the water embeds itself in the softer bearing metal and then wears the shaft.  So worth checking the shaft.

 

To check the tail shaft measure its diameter in various places with a pair of calipers or a vernier caliper(or electric equivalent) or a micrometer, depending on what you have.  Cheapo chinese electronic calipers are quite good enough. Chronos sell them for not much money, but battery life is short if you don't take them out after use.

 

  Up to about 10 thousands of an inch of wear  per inch of shaft diameter is acceptable for refitting.   So for a 1 in shaft it needs to be bigger than 0.990 in in the bearing zone.

 

Check also that the bearing has not worn bell-shaped at  the ends.  You can feel that with the unworn end part of the shaft.

 

N

 

 

[Tracy D'arth]

Was there no peg in the outer tube stopping the bronze bearing spinning?

[Slim]

3 hours ago, Roxylass said:

Any idea where I could pick one up Steve 

does it actually look in bad shape 

Norris's of Isleworth (West London near Heathrow)

That's where I got one years ago

Edited January 7, 2021 by Slim

[Tracy D'arth]

https://shop.tnorrismarine.co.uk/products/cutless-bearing-1-x-1-1-2-x-4-brass-shelled?variant=7568082665519&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_campaign=gs-2019-08-13&utm_source=google&utm_medium=smart_campaign&gclid=CjwKCAiA_9r_BRBZEiwAHZ_v1-gQjL7UsOdw6yfiO-uEdh2-WgSLRi2b-I6e_ueVwEzFp067mr4k_BoCxzkQAvD_BwE

[Roxylass]

Managed to source one from ASAP supplies 

instead of the three grease groves this one has a rubber insert with groves all round 

also been told that the prop shaft could be taken out and reversed 

dont know if there is any truth in this though 

let you know how I get on