Cutlass bearing.

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helenrose
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Joined: Tue October 31st, 2006, 2:25 pm
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Cutlass bearing.

Post by helenrose »

when i haul out my eventide 24 "Rose" i intend to replace the propshaft and also check the cutlass bearing, how can i tell what type of bearing i have in there,

thanks.

Chris.
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Fiddler's Green
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Cutlass Bearings

Post by Fiddler's Green »

There is only one Cutlass bearing sort. The Cutlass! (Trade name) It is hard rubber and fluted with the shaft running on the tips of the flute ridges and debris being washed away along the channels in between.

Reason they eventually wear is often because of a build up of barnacles and debris blocking the two water intake channels on the outer bearing holder..

To remove the bearing you have to first remove the shaft, then there may be a grub screw in the side of the outer bearing holder, once undone the bearing may pull out, but to be honest it is often easier to remove the outer bearing holder. There should be two gunmetal or silicon bronze screws securing the base, into the skeg, once undone the bearing should unscrew off the shaft.....

Once on the bench it is easier to get at.

At this stage however it may be worth touting the complete housing around the bearing manufacturers to see about replacement. some are longer bearings and may have to be shortened.

The replacement has to fit not only your shaft, but the housing...

On FG my outboard bearing is not a Cutlass. It is a plain tuphnol bearing, and even after 19 years of use is still in good order. It, like the plastic bearings that look similar, does not need a forced flow of water, but instead simply rides on a film of water.

Try Norris's of Isleworth or any Vetus stockist.

hope this helps,
Regards,
John
Proud owner and builder of 'Fiddler's Green'
helenrose
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Joined: Tue October 31st, 2006, 2:25 pm
Location: uk

Post by helenrose »

Thanks for the answer,

The last time i felt around inside with my finger it was smooth, could it be any other type of bearing?or are the grooves worn out.
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Fiddler's Green
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Stern bearings

Post by Fiddler's Green »

Hi Chris,

if it is a cutlass bearing it will be very positively ridged, with just 12 or so heavy ridges. If it were a smooth cutlass there would be 1/2 play in the shaft!

Yes there are a few other sorts of outer bearing.

I have been shipmates with a solid bronze one, with a greaser inboard that supplied it with grease.. (the whole tube was full of it!) It also had an outboard stuffing box to prevent grit geting into the bearing, very complex.

Replaced that with a standard Cutlass. lasted for years with no problems.

We also used them on our fast patrol baost at 35 knots, never saw a worn one!

Now I have a 4" long tube of tuphnol as the outer bearing, works like a dream. It is in a bronze shell secured with a small s/s grubscrew, bet it will be a pain to get out. However I went down to the boat today and vigorously shook the prop and shaft, not a slightest feel of play, so after 18 seasons use it lives on.

As I said there are polythene type ones as well, they normally have one groove down them to allow debris to escape and they fasten in a similar way, but to get some makes of them out you simply put a blow lamp on them and they shrivel and drop out, clever. New one is driven in with wooden block.

Best to see what you have in there before going much further.

Regards,
John
Proud owner and builder of 'Fiddler's Green'
helenrose
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Joined: Tue October 31st, 2006, 2:25 pm
Location: uk

Post by helenrose »

Thanks John,

I will wait till after xmas and get the boat out and take it all to bits,the reason i ask is the old propshaft has a lot?(about 1millimetre) wear where this bearing is in contact with the shaft, is this normal?i dont know.

thanks again,

Chris.
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Fiddler's Green
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shaft wear.

Post by Fiddler's Green »

Would not have called 1 mm excessive, but if it makes a noise maybe it is annoying! In which case maybe time for action.

Really there should not be enough play that you can feel it by grabbing the prop, 1 mm is about borderline maybe....

Regards,
John
Proud owner and builder of 'Fiddler's Green'
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