Tony Abbott wrote:
Question about prop and shaft rotations... we have twin engines with
counter rotational engines, 1 clockwise, 1 counter clockwise.... we also
have a LH prop and a RH prop currently not on the shafts... thus the
question...

Trying to confirm that a clockwise turning shaft in forward gear needs a LH
prop and thus a TH prop would go on a counter-clockwise turning shaft in
forward gear... can someone confirm my thoughts???

Thanks for any and all responses... and no I am not the one who removed the
props and failed to record which one came off which side...



Depends on where you view it from obviously, the usual thing is to view
it from "aft" (that's the back Harry)

Viewed from aft a right-hand propeller turns clockwise & left-hand
anticlockwise.

This causes confusion because some/most engine manufacturers, even
today describe the engine's rotation when viewed from forward (that's
the front Harry) i.e. an engine described as having left hand rotation
at it's output by "some" engine suppliers, will need a right hand
propeller (ask Gould, giggles all round here at the time; amateurs
buying from & then spruiking/spamming for other amateurs:-)). So with
your question Tony, make sure you know which engine "output shaft" turns
clockwise etc viewed from aft!!!!, the output shaft obviously turns in
the same diection as the prop (hopefully:-)), regardless of how the
engine rotation is described. (no point simplifying for Harry & his
tribe of simpletons wouldn't get this not ever, too uneducated &
basically stupid)

With counter rotating twins the preferred setup is to have the right
handed prop (clockwise viewed from aft) on the starboard side (that's
the right hand side of the boat Harry) & the left handed prop
(anticlockwise viewed from aft) on the port side (that's the left hand
side of the boat Harry)

This means that counter rotating twins should have the props turning
out away from each other at the top. So prop walk can be harvested to
advantage when maneuvering (it behaves like a wheel, at the bottom of
the prop the water is denser than the top, imagine Harry upside down).

Say trying to spin the boat to starboard with twins the starboard,
right handed prop (now turning anticlockwise from aft in reverse gear)
will try to walk the stern across towards port, the port left handed
prop (also turning anticlockwise from aft still in forward gear) will
also be trying to walk the stern to port, so even if the boat stays
almost stationary, it will assist the bow to swing to starboard. (again
no attempt to help Harry & his thugs, they're still working on the port
& starboard thing:-) no no seriously for a minute, are your elections
sort of a nation wide IQ test??? it certainly seems that way if you look
at rec.boats, the lib voters are the uneducated winers & the repubs are
the ones who take care of the real things & thankfully for me, the rest
of the free world)

K