Cutlass Bearing

parvenu · #1 03-15-2003

Does it seem reasonable that a cutlass bearing on a 33'' Beneteau used two seasons would need to be replaced? The marine surveyor who looked at the boat based his opinion on the play in the propeller shaft. When the boat was run under power any vibrations seemed to be normal.
Could this likely be something more serious or is it more probable that the cutlass bearing is simply in its early stages of wear? The engine in question is a 27 h.p. Westerbeke with 130 hours.

Any opinions would be appreciated.

George

jklewissf · #2 03-15-2003

That seems like a very short time for a cutlass bearing to last. Is the engine alignment ok?

My experience has been that cutlass bearings last more than 10 years with heavy engine use. This probably varies with the length of the shaft and alignment of the engine.

windship · #3 03-15-2003

parvenu,
It sounds to me like your engine is out of alighnment or the prop shaft was already worn in the area of the cutlass bearing.
Did you run the engine while on the hard with it in gear?
Has the strut been whacked and bent? If the shaft ok and the strut isn''t bent, do this...since you can''t perform this test with a worn out CB,replace the bearing and reinstall the shaft. Make sure the bolts that connect the tranny output flange and the prop shaft flange are tight and there are no problems in that area. Now look at the rubber in the bearing where the shaft enters the CB and where it exits the CB. You should see the rubber buldging on one end of the CB and opposite of it on the other end. Now you can adjust your engine alighnment.
Good luck,

Dennis

RichardElliott · #4 03-16-2003

Could your zinc "football" be too close to the cutlass bearing? I was told that it must be at least 2 1/2 shaft lengths away for proper cooling.

parvenu · #5 03-16-2003

Richard (and others who were so kind to respond),

I don''t think the zinc is the problem since it''s a special zinc fitting that is specific to the Beneteau. I suspect that as has already been opined, the culprit is the shaft and/or alignment with the engine. There doesn''t seem to be any other explanation. There''s no way you should run through a cutlass bearing every couple of years.

Thanks to everyone who replied. And if anybody else has any thoughts (even if it''s just to agree with something that''s already been said), I''d appreciate hearing from you.

George

JERH · #6 04-15-2003

check Author Tom Wood/Drive Train Vibration - www.sailnet.com/collections/articles
I have same problems on my 1980 Cal 39!

petercra · #7 04-15-2003

Take a look at how it is worn. If the shaft is out of alignment you''ll notice the cutlass bearing is more worn on one side of the shaft than the other. Check both the fore and aft sides of the strut. If the problem is alignment the assymetrical wear will be 180 degrees apart on the two ends of the strut (the reason for all of this should be obvious, just draw yourself a diagram of the strut, shaft and cutlass bearing).

I''ve had my 33 footer for 12 years and am just replacing the cutlass bearing for the first time. I noticed that one side of the rubber in the bearing is 1/16" while the other is 1/8". Last year I had the engine bolts tightened, I suspect that this might have thrown the alignment out.