Ed Anderson Wrote:

[snip] But, it was our first cold morning having dropped down to 39F that night,
So I though it must just be that heavy 50 wt oil being a bit sluggish.
[snip]
The [nickel] plating had proceed to flake off of the bronze and while most of it
apparently went into the sump with no problem, some of it got "smeared" into the
bronze bearing.  As more of the nickel built up there it reduced the rather
small clearance between shaft and bronze bearing until it finally caused the
shaft to stop or rather become very difficult to turn.  It apparently had not
yet seized although it was well on its way to doing so in another few
revolutions.

Ed,
I'd speculate that you found it when you did because of the difference coefficient
of thermal expansion between the bronze bearing and the prop shaft.  The bronze
bearing has a Cte of about 10E-6/degF while the shaft Cte would be about
6.8e-6/degF (steel 4140).  As the temps got colder, the clearance got tighter.

Russell Kent

 
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