Owner`s manual

Running
Sport Boat
7-7
PROPELLERS
The propeller converts the engine’s power into the
thrust needed to propel the boat. Care and selection
of your propeller is very important to proper boat
operation. Propellers are identified by two numbers,
such as 13 x 19, and a material identification, such
as aluminum or stainless steel. In the number
sequence, the first number is the diameter of the
propeller and the second is the pitch.
Pitch is the angle of the blades
expressed in the theoretical
distance a propeller travels in
each revolution. In the above
example, the pitch is 19, or each
revolution of the propeller
pushes the boat 483 mm (19 in.)
through the water. A 19 pitch is
considered “higher” pitched and
a 15 pitch propeller is considered
“lower” pitched.
Keep these guidelines in mind when selecting a propeller:
• There are many different propeller designs for specific operating
characteristics, including the number of blades, relief holes and
cupping. DO NOT attempt to change propellers until after you have a
chance to determine your average load and individual requirements.
Your dealer is best qualified to help you select a propeller.
• Engine RPM must be within the recommended operating range. Refer
to the engine operator’s manual.
• Higher propeller pitch reduces: RPM, acceleration, engine noise, and
usually improves fuel economy and top speed.
• Lower propeller pitch increases: RPM, acceleration, engine noise,
reduces fuel economy and top speed.
DIAMETER
KC-1580
KC-1581
PITCH
(ONE REVOLUTION)
KCC_SportBoat_Book.book Page 7 Tuesday, December 5, 2006 7:19 AM