I replaced the shaft on my Catalina 42 due to wear and tear. The shaft
had to be taken out once because the threads were damaged in the
installation. When completed, alignment could not correct a 0.007-inch
gap that moved with the shaft, suggesting a slight bend. There’s a 4-inch
coupling. Would you pull the shaft to align it with this small deviation
from acceptable tolerance? Andrew Soll
Pacif ic Palisades, CA
DON CASEY I doubt your problem is a bent shaft. When the gap moves with rotation
of the shaft, this is nearly always caused by the flange being crooked on the shaft, but it
can also be due to distortion of the flange. On a 4-inch coupling, the acceptable maximum flange run-out is 0.004 (0.001 per inch of flange diameter). It’s not what you want
to hear, but you need to pull the shaft again and take it and the flange to a prop shop
to have it trued. They will also clean up the bore so the flange will be a slip fit when
you reinstall, which will save the insult to the threads and to the transmission bearings.
Failure to do this now will almost certainly cause you headache and expense later.
Practical Boater ASK THE EXPERTS
Edited by Tom Neale
I want to install a new toilet in the head,
and use raw water to flush. The only
seacock on the boat is the engine-cooling
raw-water intake. Is there a way I can
draw my raw water for the toilet from
this inlet, and avoid drilling another
hole in the boat? Donald Wolter
Alex Bay, NY
TOM NEALE While it’s a good idea
to not make more holes in your bottom,
I wouldn’t recommend teeing off your
engine’s raw-water cooling intake line
to supply your head’s intake. The engine
needs an uninterrupted and unimpeded
flow of water to feed its pump and to
circulate through the heat exchangers
and cool its exhaust. While it’s possible
that teeing off that line may not result
in any problem, it’s also possible, maybe
even probable depending on your plumbing and head, that doing so could cause a
decrease in flow to your engine. Examples
of things that could theoretically cause
this include creation of vacuum, introduction of air into the line, or obstruction
of the flow from the “T” plumbing itself.
You might not know whether it’s going
to be all right until the damage is done.
And if these or other issues were to cause
diminished flow to the engine, the damages could be very expensive.
I have a 25-foot Farallon. The bow deck
delaminated, so I removed the foam
board from belowdecks (topside is perfect). I cut a piece of marine half-inch ply
to fit and glassed the bottom of the wood.
What can I use to attach it to the underside of the fiberglass deck? I was thinking
of using thickened epoxy resin with a
notched trowel (like a reverse floor-tile
installation), then screwing from above.
JOHN ADEY I wouldn’t use screws
from the top, which would create another
set of holes to seal. After a thorough ILLU