Improved Thrust

[Ron Capron]

I recently purchased an older Catalina 30 with a Universal Atomic 4. It is a 1979 Model and in reasonably good condition. The previous owner mentioned that if he had kept the boat he was going to invest in a three bladed prop. It presently has a two, of which I have no idea of the pitch. If I were to upgrade to a three bladed prop, based upon the weight and power of the engine and boat, what would be the most reasonable combination. During this past winter I toured the local boatyards and found that at least 80% of the Catalina 30's of comparable vintage were using a three bladed propeller. Could you help me with some information on the subject? Thank you very much for your anticipated assistance. Ron Capron

 

[Richard]

Forum archives

Ron,Go to the forum archives and type in "3 bladed prop"The subject as been throughly discussed...Cheers!

 

[Kevin l. Woody]

Atomic four

Dear Ron;Thanks for your note. We show in our records a 12” x 5” three blade for an Atomic Four motor. I would look at the currently installed propeller determine it’s pitch and diameter. From there remove one inch of pitch and add a blade. This should equal out to two comparable units. You could apx. expect a 30% increase of efficiency when you convert to the three blade. This increase will result in retaining of power when you are confronted with heavy winds or seas. You should also see a decrease in noise and vibrations.Hope this helps.