Using boat with worn cutlass bearing.

[fredrussell]

By cutlass bearing needs replacing. There’s approx 2mm of play in prop shaft, or at least there was when I dived under boat 3 months ago. I keep my boat in, and sail, year round. Boat was due to be lifted at the end of summer but due to various factors my yard are only now able to hoik it out. I would rather lift boat pre season next year, say April, and anti foul it at the same time.

My question to the panel then, is will motoring with a sloppy cutlass bearing for three or four months damage anything? I probably average an hour of motoring per week through winter months - no long voyages, just manoeuvring in and out of marina mainly. I ran engine in fwd and reverse in my berth yesterday and there were no ‘bad vibes’, and watching the prop shaft inside boat there’s no discernible movement - ie prop shaft is not ‘blurred’ to look at. If it makes any difference it’s a YANMAR 3GM30, with a PSS shaft seal and Kiwi prop. There’s no P-bracket, cutlass bearing sits in ‘skeg’. This on a Parker 31.

 

[Graham376]

As long as there's no excessive vibration, keep using it.

 

[andsarkit]

2mm seems a lot.
I have a 1GM10 with fixed stern gland and tufnol sleeve for cutlass bearing. When I had 1.5mm play there was a noticable knocking and I only got the 100 miles home by pumping in lots of grease. The single cylinder engine vibrates quite a lot which doesn't help.
Damage will probably be accompanied by nasty noises so as long as it is quiet you are probably fine. Watch out for any resonance and try to avoid using those revs. If the rubber in the cutlass bearing has completely worn away you might get wear on the shaft rubbing on the brass outer but I don't think you are there yet.

 

[srm]

Last time I had a survey done the surveyor noted a couple of mm play and verbally suggested that the cutless bearing should be changed fairly soon. It did not get a mention in the report, but then there were a lot of gross errors in the report.

Size and length of shaft should be taken into account, but as suggested above, if there is no adverse vibration I wouldn't worry for the amount of usage you envisage.

 

[Beneteau381]

By cutlass bearing needs replacing. There’s approx 2mm of play in prop shaft, or at least there was when I dived under boat 3 months ago. I keep my boat in, and sail, year round. Boat was due to be lifted at the end of summer but due to various factors my yard are only now able to hoik it out. I would rather lift boat pre season next year, say April, and anti foul it at the same time.

My question to the panel then, is will motoring with a sloppy cutlass bearing for three or four months damage anything? I probably average an hour of motoring per week through winter months - no long voyages, just manoeuvring in and out of marina mainly. I ran engine in fwd and reverse in my berth yesterday and there were no ‘bad vibes’, and watching the prop shaft inside boat there’s no discernible movement - ie prop shaft is not ‘blurred’ to look at. If it makes any difference it’s a YANMAR 3GM30, with a PSS shaft seal and Kiwi prop. There’s no P-bracket, cutlass bearing sits in ‘skeg’. This on a Parker 31.

Beneteau etc use a rubber cutlass bearing, brand new there is about a 1mm bit of play. 2mm is only 80 thous. If no noise or noticeable movement then carry on surely?

 

[fredrussell]

Thanks all. That’s reassuring