[Public-List] stern tube question

[David Fay]

Mike,

But isn't it also possible that the engine/gearbox is aligned with the stern tube but the prop shaft and its flange are not aligned with the gearbox and its flange? What I have in mind is that my flexible coupling, which sits between the prop shaft flange and the gearbox flange, might be damaged (or flexed). In that case, the prop shaft should wobble when I rotate it.

I don't know if this is even possible, but it occurs to me that a flexible coupling might not behave like a rigid flange bolted to another rigid flange.

David
Blue Teal #284

> On Jan 31, 2019, at 4:55 PM, Mike Lehman via Public-List <public-list at lists.alberg30.org> wrote:
> 
> The cutlass bearing housing dictates the tube alignment.  If the shaft is
> not centered in the tube, the the engine is out of alignment. It is highly
> unlikely to bend a shaft that is 7/8" as short as the A30 shaft...there
> isn't enough leverage.
> 
> On Thu, Jan 31, 2019, 4:31 PM David Fay via Public-List <
> public-list at lists.alberg30.org wrote:
> 
>> Clay,
>> 
>> Interesting that you mention shaft alignment because, when I removed my
>> bearing housing, my shaft was not centered in the stern tube. I'm about to
>> tackle that problem. If it is off-center but doesn't wobble, I guess I have
>> an alignment problem. If it does wobble, either the shaft is bent or the
>> shaft is not aligned properly with the gearbox flange.
>> 
>> I think the problem began when I had a bad rope wrap around the prop shaft
>> last fall in a squall. It didn't stop the engine but the rope melted from
>> the heat. Since the rope was attached to the bow of the boat (a long
>> unstowed bow line), it could have exerted some sideways force on the prop
>> shaft when the rope tightented. I doubt it would be enough to bend a 7/8"
>> stainless steel shaft, but what do I know.
>> 
>> Complicating the whole matter is that I have a flexible coupling between
>> the shaft flange and the gearbox flange. It could be that the flexible
>> coupling was damaged and needs to be replaced. Or perhaps just re-aligned.
>> We'll see.
>> 
>> David
>> Blue Teal #284
>> 
>>> On Jan 30, 2019, at 9:59 PM, Clay Pass via Public-List <
>> public-list at lists.alberg30.org> wrote:
>>> 
>>> I would check to make sure the shaft is coming directly out of the center
>>> of the stern tube and rotate it by hand to make sure it doesn't wobble on
>>> rotation.
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