Propellers have two basic dimensions;
diameter & pitch. Diameter is the distance
measured across the propeller hub line from
the outer edge of the circle that is made
by the propeller's blades during rotation.
Pitch is the distance that a boat will travel
if rotated one revolution without any slippage.
When describing a propeller both the diameter
and pitch are given. The diameter is referenced
first and the pitch is second. Therefore,
a 12'' x 9'' propeller would have a 12-inch
diameter and a 9-inch blade pitch.
Theoretically, a propeller with a 14-inch
pitch, when rotated one full turn, would
advance a boat 14inches through the water.
In reality, no 14-inch pitch blade will
advance a boat 14 inches with one full turn.
This variance is referred to as slippage.
in general, changing to a higher pitch prop
will increase your top-end speed but reduce
your acceleration (reduce your ''hole-shot''
power). On the other hand, decreasing the
pitch will increase your hole-shot but sacrifice
some of your top-end speed. If the hole-shot
speed is important to you, for example if
you pull water skiers most of the time,
then you would want to go with a lower pitch
prop and sacrifice some of your top-end
speed but increase your hole-shot speed
to get the skiers up faster.
Under no circumstances should you ever use
a prop which will allow your outboard to
operate above the outboard's recommended
maximum RPM's!
The propeller selection chart can be used
to help you in selecting the correct propeller
for your Tohatsu outboard. Remember that
in any application, discrepancies in performance
can result due to the different boat hull
designs, the final carrying load and your
particular needs.
NOTE: It is highly recommended that the
outboard be checked with a tachometer to
ensure that the engine is operating within
the correct MAXIMUM RPM RANGE.
