True. 2 points to you Jeff.

Would you know if tapering the shaft is the
standard? I haven't seen any otherwise, but my
experiece is limited to puling props on only a few
boats.

I was wondering if some shafts come straight with
just a key way to lock them in position?

Bart Senior

Jeff Morris wrote

I'll take some of those points - It was me, not Neal, that pointed out
that the gearing could well be different in reverse. I also pointed out
that it would be easily noticeable.

Curiously, his first answer, that the prop was mounted backwards, may
have been a better answer. That doesn't change the handedness, but if
the blade is not symmetrical it will affect the efficiency.