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posted to rec.boats.cruising,rec.boats.building
Roger Long
 
Posts: n/a
Default Drive alignment (was) Drive Saver/Spacer users sought

If you used a grinder on those coupling faces, I would strongly advise
pulling the shaft and having at least that coupling trued up. At the
same
time, they can check for straightness, wear that will shorten bearing
life,
prop taper fit, etc. Straightness is a greatly overlooked issue,
especially
in the long shafts that many pleasure boats have. The offcenter mass
in the
middle pulls the shaft out of line which puts the mass farther from
the axis
of rotation. The result is many pounds of steel spinning off center.
It's
tough on your rear end, your ears, and all the bearings in the system.
It
can also work your flexible stuffing box overtime.

The transmission is a tougher matter but the fit on the shaft is apt
to be
better than the prop shaft since it was presumably done at the
factory. I
would pull that coupling and have them do what they can with it. You
might
also look into buying one that fits and is full round so you can align
and
check it more easily. Buy or rent a dial gauge and check it in the
boat
after reassembly.

It's always painful to insert a major project like this into the
schedule at
this stage but you are going to spend many hours listening to that
engine.
Vibration increases fatigue and weakens components in other systems.
If it
isn't smooth, it's going to cost much more time and money to fix it
later.

You don't have a thrust bearing so you can't put in anything soft
enough to
accommodate any real misalignment. A Drivesaver will mitigate but
it's only
going to take the edge off the kind of problems you could have in that
coupling.

Friend of mine has the identical boat. With the same kind of prop,
his
vibrates like crazy while mine is smooth. I haven't touched my
shaftline
yet so it's just luck but it does show that subtle things can have
large
effects. He has a Drivesafer too.

Sound like you are going to be sailing off over the horizon. You are
really
going to be depending on that engine. This is the time to be sure the
shaftline is right.

--

Roger Long