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.
N1EE wrote:
5 points to Neal.
Inboard diesel powered boats commonly have different
gearing in reverse.
Incorrectly installing a RH or LH pitched prop when
the opposite was called for could cause a boat to
run at slower than expected speeds, albeit it would
move forward in the reverse position and vice versa.
Neal immediately grasped that the gear ratio might be
wrong and this could be explained by the boat running
in reverse, and at a lower gear ratio.
Capt. NealŪ wrote
If the shaft has a taper there is no way to put it on
backwards so, perhaps, they shipped a LH prop instead
of a RH prop or vice versa? Diameter and pitch could
be identical but it would be so slow if turning
direction were wrong.
CN
"Capt. NealŪ" wrote
Remove it, turn it around, put it back on.
CN
"Bart Senior" wrote in
5 points (Impress me with your genius)
You just bought a new boat and notice the prop is old and brittle.
You replace it with an identical prop. After motoring around for a
while you find the top speed of the boat is much lower, estimated to
be 2.5-3 knots and the prop seems to be slipping.
What is the most likely cause, explaination, and cure?
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