[Public-List] Stern Tube Repair

[George Dinwiddie via Public-List]

Hernán

On 8/24/17 5:25 PM, Hernán Scarnichia via Public-List wrote:
> George,
> Thanks for your email.
> Do you have any pictures of the stern tube once out of the boat?
> 
> If I build a new fiberglass stern tube the fiberglass tube will project
> outside of the hull and receive the cutless bearing. so I wouldn't use the
> casting.
> This is a bigger job that I would like to avoid.
> But I am worried that the clearance between the tube and the shaft is too
> small: 3/16 or 1/4 all around the shaft sounds OK but that would require
> the INNER DIAMETER of the stern tube to be at least 1-1/4. I measured the
> OUTSIDE DIAMETER of the tube and it is 1-5/16, which makes me think that
> inside it will measure 1 inch (schedule 40 pipe). If the tube is one inch
> inside and does not move (the caulking supports it) then if everything is
> aligned perfectly it would leave a 1/16 clearance, which means if the
> engine moves more tan 1/8 the shaft would contact the tube.
> 
> I guess this is close fit is normal.
> 
> I had not thought of the tube vibrating... its very possible
> 
> is the inboard end of your tube rigidly fixed after re-bedding or can it
> move a little bit?

It can move a little bit, but is held by the outboard end being screwed 
into the cutless bearing housing.

> how long is the hose in your stuffing box > maybe my hose is too long or too flexible to keep the shaft centered?

4 inches of stuffing box hose, which is considerably stiffer than 
exhaust hose.

  - George

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