SF37 or SO37 Cutlass bearing!

[snwl]

The next time I raise the boat, I intend to replace the shaft bearing (Volvo Penta), SD55, and somehow it seems wise to also replace the cutlass bearing. I need help here. I assume SO37 and SF37 have the same bearing dimensions. What are the dimensions of the bearing (metric)? Shaft size is 25 mm. Is the bearing fully rubber or is it bronze with vulcanized rubber? Thanks for the help.

[vasko]

Sept 19, 2019 7:50:10 GMT snwl said:

The next time I raise the boat, I intend to replace the shaft bearing (Volvo Penta), SD55, and somehow it seems wise to also replace the cutlass bearing. I need help here. I assume SO37 and SF37 have the same bearing dimensions. What are the dimensions of the bearing (metric)? Shaft size is 25 mm. Is the bearing fully rubber or is it bronze with vulcanized rubber? Thanks for the help.

What is shaft bearing ?

The new boats are usually with full rubber cutlass - but I usually prefer a composite one ... keep in mi d that over time and vibration the cutlass dimensions change slightly ... e.g my one should be 36mm but it is actually 36.2-36.3 - and in the end the mist important task after everything is done - is to align PROPERLY the shaft - this is DONE when the boat is IN the water! and need to be done precisely if a corner is cut there - the results are not good at all..,

[snwl]

Yep my mistake. Shaft beraring = shaft seal.

[jcoughlin]

The SO is all rubber and 25mm diameter. I purchased mine from ASAP-Supplies in the UK.
Cheers

[vasko]

I usually buy this type of parts from :

www.sillette.co.uk/

[jcoughlin]

People often wonder about the all rubber design of the cutlass bearing.
I believe it was designed in part to allow easy removal (by hand, no tools required) of the prop shaft and bearing itself.
With the cutlass bearing removed there is enough room to tilt the shaft to clear the rudder when removing.
Although we don’t have a long season where I’m located ( Maine, USA), I get approximately 5 years before I replace mine (3rd Jeanneau).
cheers

[mikes261]

I was advised to change my all rubber cutlass bearing by the surveyor when I purchased my 2002 SO37 this summer. I had the bearing replaced professionally whist the boat was on the hard but after about 40 hours motoring there is ~2mm play between the shaft and bearing, which leads to my questions;

1, should there be any movement in with an all rubber bearing? 

2, An 2002 SO40 in the club (just so happened to be out of the water at the same time) has a brass/rubber bearing and there is no play at all between bearing and shaft. Is there benefit to change from all rubber to brass/rubber bearing?

Thanks  

[sitara]

All rubber cutlass bearings are fine in my opinion. If they are wearing fast then something is causing that wear. My previous boat (SO29,2) had a worn cutlass bearing at four years of age when I purchased it. On removing the bearing I found the shaft coated with an abrasive layer (calcium?) and assume some marine life had set up home in and around the bearing. Fitted a new all rubber bearing and it was still as new when I sold the boat. My current boat has a seven year old bearing as that is still fine.

Also all rubber bearings are very easy to change.

[mikes261]

Thanks Sitara, I will take things apart and investigate. Perhaps the wrong ID bearing was used when it was recently renewed.

[jcoughlin]

There will be some movement between the shaft and the cutlass bearing but it should be very little.
If you have 2mm of play I suspect that the rubber has worn prematurely due to some outside force. Is there excessive vibration under power, is the shaft smooth under the bearing?

[mikes261]

I need to remove the bearing to see the condition of the shaft under the bearing. the shaft needs a clean but other than that looks fine.

I would say there is no vibration under power but this is a new boat to me and others may say yes there is some thing there. There is certainly no vibration being felt through the wheel and the Volvo Penta MD2040 under different power loads is not vibrating excessively in anyway. 

I was going to start another thread regarding my prop but it may be linked to the bearing issue...…...the prop is a two blade folding prop (possibly Flexofold) 17/11 right hander. The problem with this is it is very pitted, mainly on the body but also some on the blades. This was not picked up on the survey so I suspect it has happen in the last two months.

I have taken the boat from being berthed in salt water to fresh and the Zinc anodes had tarnished. Whether or not the tarnishing has happened in the two months it has been in fresh water I don't know. I am asking myself has cavitation taken place over the 40hours of engine use on the delivery trip home. This is the only time I have used the boat due to work and other commitments so I am on a learning curve for this boat.

Mike

[johannes]

Mike, I think nowadays magnesium anodes are recommended for fresh water. But I doubt that can be the only reason for the pitting in just two months. It sounds more like galvanic corrosion.

Flexofold had a quality problem some years ago with the body of the propellers. The blades were manufactured by Flexofold themselves and made of high quality marine bronze, but the body was milled from cylindrical blanks from a supplier that had a production problem.

[MalcolmP]

Oct 22, 2019 20:29:34 GMT mikes261 said:

........

I have taken the boat from being berthed in salt water to fresh and the Zinc anodes had tarnished. Whether or not the tarnishing has happened in the two months it has been in fresh water I don't know. I am asking myself has cavitation taken place over the 40hours of engine use on the delivery trip home. This is the only time I have used the boat due to work and other commitments so I am on a learning curve for this boat.

Mike

Mike

You may well be best to use activated aluminium for the anodes if you are regularly shifting from fresh to salt, such as within Cardiff barrage. Ben Sutcliffe www.bensutcliffemarine.co.uk/ has a lot of experience in your area with avoiding cathodic  protection and electrolysis - might be worth giving him a call

Malcolm

[mikes261]

Thanks for the advice on the anode material and prop.

This weekend a managed to get the old prop off the drive shaft to discover the shaft has been extended and there are signs of an old woodruff key slot in the same position as the P-bracket/Cutlass bearing. The whole thing looks like a bodge job and just by looking at it I believe the extended section is not aligned perfectly to the rest of the shaft which has caused the new cutlass bearing to go so quickly. Some point in this boats life the shaft has been replace because this would not have come from Jeanneau like this.

I will now replace the shaft, bearing and prop to ensure everything is right.

Mike

[sailygirl]

Hi Mike, 
I have a Sunast 37.  We have lost the prop, nut and keyway.  Di you have any detail re the nut and keyway size.  We think it is a M16 1.5 fine thread.  and a keyway 6 x 6 x 45m.  Thanks for any help on this one.