If your prop is too small, no amount of experimenting with number of blades or pitch will give you quiet cruising in
calm conditions, crisp maneuvering astern, low drag under sail and the ability to punch through a head sea. Only larger diameter
props give you all these benefits.
The chart shows the typical propellers suggested for the Catalina 30 motor combinations,
the normal 2 blade propellers suggested by catalina, and the performance Propeller recommendation. Note the size difference
for the performance propellers recommendations for the geared diesel engines. The E preceding prop size designates an extendo
propeller. That fits perfectly on the Catalina 30 and allows a larger propeller to be used.
Our Extendo props are a simple, easily installed way to replace undersized props. We designed a prop with an integral
6 inch long extension on the front. Because of the downward slope of the shaft and the upward slope of the hull, the 6 inch
hub extension lets you swing a 2 to 3 inch larger prop.
The Extendo concept is particularly useful for vessels that have replaced Atomic 4 direct drive motors with modern diesels
that have a gear reduction. Most boats that were designed for use with the Atomic 4 direct drive only have room for a 12-13
inch prop. Diesel replacements usually work better with 14, 15, or 16 inch props. The Extendo hub makes it possible to use
a larger propeller with the new engine.
More information about the EXTENDO propeller.