The Proper Props
Grady-White incorporates the latest propeller technology for efficient, reliable operation.
The numbers and letters associated with a boat’s propeller
designation often don’t mean much to boat owners. When we are talking
about propellers, a 15½ × 17 is NOT a multiplication problem! These
numbers convey the propeller’s suitability in delivering reliable and
efficient performance. Using the right propeller can ensure that your
boat is as much as 30% more fuel efficient. Check our website performance reports found in View Details for each model to see what we test, use and recommend for new Grady-Whites. Your dealer can help with your needs for older Gradys.
The basic propeller desig- nation is straightforward. For a 15½ × 17, the first number refers to the prop diameter,
or the distance across the circle made by the propeller blades when
rotating. The second number in the description refers to the propeller pitch,
or the ideal distance in inches the boat moves with a single revolution
of the propeller, e.g. 17 inches. The lower the pitch, the lower the
“gear,” meaning you get on plane quickly with a low pitch, but at some
penalty on the top-end speeds. Also, the smaller the diameter, the
higher the pitch can be for a given boat/motor combi- nation. With the
larger four-stroke V6 and V8 engines or inline 4-cylinder engines used
on Grady-White boats, we can power higher diameter props to achieve the
desired level of efficiency and performance. A great deal of testing
goes into the props that we recommend and install, and your dealer is a great source of knowledge about the right kinds of props for you. See our Customer Tips area for more tips for better efficiency and performance.
Other letters you may notice in the propeller technical description
like “M” and “SS” and “SSII” refer to Yamaha’s propellers series
designation. However, an SDS (Shift Dampening System) designation refers
to the prop hub, indicating a kind of shock absorber mounted on the
shaft that ensures a smooth, even shifting into gear, as well as making
it easy to interchange various propellers.
Even the rugged and durable stainless steel propellers we use on
every new Grady-White will get nicked and dinged from normal use and
should be inspected regularly to avoid vibration, noise, and lesser fuel
economy and performance. Performance can be reduced by ten percent or
more depending on the damage. A professional prop shop can recondition
most minor damage. See your dealer if you experience more serious damage.