New cutlass bearing - squeal at certain revs. Will it wear in?

[frlrubett]

Recently replaced cutlass bearing as it was excessively worn. Prop shaft was 1 inch but the chandlery said that the 25mm bearing would be fine and should wear to fit perfectly. Also the previous bearing was 2.5inches long and they only stocked the 4inch long bearing, so new bearing is longer and tighter.

Did not think much about this but used a bit of elbow to get the bearing on. Can be turned by hand but does not spin freely in the slightest. It is definitely tighter that it was before, but the preivous bearing was shot.

First time back on the water. Idle no issue, high revs no issue but medium rev's there is a squeal / wine sound from the prop shaft - this was not there before. This happens all the time and does not seem to relent currently...
Thoughts?

 

[Tranona]

Sorry but your chandler is absolutely wrong. I had that happen once when a contractor put a 25mm cutless in the housing when I ordered a 1". It definitely will not wear in. Why do you think they make both sizes? The 0.4mm difference is critical.

4" is standard length (4* diameter), and your 2.5" is very short. What sort of stern tube is it? Just over 3" was common years ago on Stuart Turner stern gear. Normally the excess would be cut off to ensure that there is still a 15+mm gap to the propeller.

 

[ash2020]

I agree, I'm afraid. 0.4mm is a big difference.

 

[frlrubett]

Attached photo of reassembly.

 

[PCUK]

Although it is the wrong size it will be OK. Mine used to whine even though it was the correct size.

 

[Sandy]

Thoughts?

The chandlery staff need to either:

• go back to school; or
• speak to a mechanic who understands about measuring things.

 

[Metalicmike]

I would borrow an adjustable reamer, it could wear in and wear in un evenly reducing its life. It could also be putting excess stress on your gearbox.

 

[MoodySabre]

A cutless bearing in a P bracket gets lubricated by water running through it. How does yours get lubricated? Is the additional length interfering with water flow through it?

 

[frlrubett]

Yes siutation is not ideal I am aware.

I am planning to haul out end of September with a few weekends away planned on boat before then - which we only ever go when it can be under sail with minimal engine use. I plan to change this over the winter to the correct one, unless there could be a major problem rearing its head.

Furious with the chandlery - a reputable solent one.

 

[Tranona]

I would borrow an adjustable reamer, it could wear in and wear in un evenly reducing its life. It could also be putting excess stress on your gearbox.

Can you explain how you would ream a fluted rubber bearing? You seem to have a knack for not understanding the subject of the question.

 

[Tranona]

Although it is the wrong size it will be OK. Mine used to whine even though it was the correct size.

No it won't. If it was OK then there would be no need to make bearings to match the shaft diameter. 1" is 0.4mm MORE than 25mm.

 

[Tranona]

Attached photo of reassembly. View attachment 181409

That looks pretty grim. Sometimes those short bearing carriers do not have a lip inside so part of the cutless goes forward of the deadwood. 2.5" is really too short and if that were mine I would look at either a new longer housing or cut the cutless down to 3" leaving 1/2" outside. The shaft needs shortening then to reduce the overhang between the cutless and the face of the propeller to 20mm for water to flow into the cutless.

 

[Metalicmike]

Can you explain how you would ream a fluted rubber bearing? You seem to have a knack for not understanding the s

Can you explain how you would ream a fluted rubber bearing? You seem to have a knack for not understanding the subject of the question.

I like many others thought they were phosphor bronze. So we have all learnt something, thank you or is it better not to comment and learn nothing ?
ubject of the quesi

 

[RivalRedwing]

Either
Lake Engineering Lake Engineering Ltd
or
T Norris T.Norris Marine. Supplier of Propellers, Stern Gear & Marine Equipment
would be good places to start properly resolving this.

 

[38mess]

Could possibly wear the prop shaft down rather than the cutless material. Best get it right to start. I know when I removed my 1" shaft at the start of this summer to have it checked over there was slight wear at the cutless area, but a lot of wear at the stern gland packing area where I had overtighten over the years, so I renewed everything, the old gear had done 35k nautical miles so the new stuff will see me out.
Get it right to start, you can't bodge these things

 

[vyv_cox]

A cutless bearing is more properly called a 'cutless rubber' bearing. In the 1920s rubber bearings were substituted for lignum vitae hardwood bearings in water pumps and were found to be better for the shafts, as they "cut less". When Goodrich took over production they confusingly used a cutlass logo to promote them, leading to spelling confusion ever since. The Cutless name is now proprietary to Duramax, although like Hoover it is widely used to describe all makes.

 

[scottie]

I am refraining from commenting on suppliers advice.
But unfortunately Metric bearings will normally be metric bore and outer shell whilst imperial measured in inches so you have a basic check
Except for the Bastardised versions which have a mixture

Old carpenter advises measure twice and check cut once

 

[Tranona]

I am refraining from commenting on suppliers advice.
But unfortunately Metric bearings will normally be metric bore and outer shell whilst imperial measured in inches so you have a basic check
Except for the Bastardised versions which have a mixture

Old carpenter advises measure twice and check cut once

25mm ID is available in all 3 of the common Imperial ODs that are also available 1" ID. Metric 25mm ID is 40mm OD. Many British boats (including mine which has an 1 3/4" OD 30mm ID) are made with Imperial carriers and metric shafts so as you say important to measure the shaft and fit the correct ID. The error here is with the supplier as the OP asked for the correct thing.

 

[Bilgediver]

Yes siutation is not ideal I am aware.

I am planning to haul out end of September with a few weekends away planned on boat before then - which we only ever go when it can be under sail with minimal engine use. I plan to change this over the winter to the correct one, unless there could be a major problem rearing its head.

Furious with the chandlery - a reputable solent one.

I expect that the chandler assumed you would cut the excess off. This would reduce your problems by reducing the friction as well as giving the water better access to cool and lubricate,

When winter comes just cut of the excess and open up with a 1 inch reamer which you might be able to borrow .A correctly adjusted expanding reamer would be better but difficult to find so it might require bearing housing removal and boring in a lathe as the bore needs to be opened up by at least 0,5mm

 

[Fr J Hackett]

I expect that the chandler assumed you would cut the excess off. This would reduce your problems by reducing the friction as well as giving the water better access to cool and lubricate,

When winter comes just cut of the excess and open up with a 1 inch reamer which you might be able to borrow .A correctly adjusted expanding reamer would be better but difficult to find so it might require bearing housing removal and boring in a lathe as the bore needs to be opened up by at least 0,5mm

Highly unlikely that a reamer would work especially with a "rubberised" compound that would deform rather than cut. If you take it out to put in a lathe, a dubious outcome as well you might just as well buy the correct bearing and be done with it. The OPs real problem is that if he continues to use it for any length of time he might well find the shaft marked / scored which could result in problems with the correct bearing. Unfortunately he is back in the water now and any action either to alleviate the problem, like cutting the bearing back to help with water flow and lubrication, is going to require two lifts and additional expense and at that point he may as well bite the bullet which includes shortening the prop shaft to reduce the prop overhang as Tranona has pointed out.
A right buggers mess.