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Charles T. Low
 
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Default B-W Velvet Drive clunking

Tom,

As others have already explained, this is a straight-shaft inboard setup,
pretty standard, I think, and it is not horizontal. You can see a photo at
www.ctlow.ca/Trojan26/Rudder2001.JPG, from my Ksenia page (address below).
No U-joints, and no "shock absorbers" - the shock is absorbed by the water!

I think it would be more efficient if it were horizontal, and on some
displacement hulls (a few) it is, but on a planing hull I think it just has
to angle down. Building a casing below the hull to contain a CV joint which
would then allow the shaft to run horizontally would not be
"hydrodynamically" efficient either, I don't think - might as well have an
I/O - pros and cons! I do depend heavily on trim tabs to maintain attitude
when on plane. ("Slow" plane, which is all this boat does!)

The cutlass bearing referred to elsewhere is in the housing at the bottom of
the strut in the photo referred to above. The prop shaft is stabilized by it
and by the passage through the hull and then at the transmission. Apparently
very long shafts require extra supports, but for most of us that's a typical
arrangement. If the shaft were misaligned with the tranny, or just not
straight enough, then that would cause vibration and premature wear of all
sorts of things (I guess), but not the behaviour I'm describing. At least,
not directly.

I have, by the way, checked the prop, by hand, but it seems absolutely
solid.

====

Charles T. Low
- remove "UN"
www.boatdocking.com/BDPhoto.html - Photo Contest
www.boatdocking.com
www.ctlow.ca/Trojan26 - my boat

====

"Short Wave Sportfishing" wrote in message
...

It just occured to me - does the drive train have U-joints? If so,
then that's the most likely cluprit.

Good luck.

Later,

Tom
S. Woodstock, CT