Prop diameter?

[dy168]

Hello,<br /><br />I have the 2004 3.0 Alpha I I/O sterndrive. Planning to ugrade to a SS prop. I checked the current prop pitch on the prop and its a 21. I can't confirm what diameter it is without really measuring it. I just called the dealer, they told me its 14" according to the part manual for the 2005. But when I called last year, they told me its 14 1/4". Dealer said they might have changed since last year. Does it really matter if the diameter difference is +/- 1/4" if the pitch is correct? Will this affect the RPM?<br />Thanks.

 

[ufm82]

Re: Prop diameter?

1/4" won't have much effect- that's only an additional 1/8" or so on each radius. If you are changing from a 14" aluminum to a 14 1/4" stainless, the extra efficiency of the stainless steel will overcome the difference in diameter. However, the blade design will be different on the stainless wheel- cupped blade, rake, etc will probably be different than the aluminum prop. What is your current prop and what are you going to? What size boat? And, what is your application? Skiing? Tubing? Fishing? Speed? All these factors should be weighed. <br /><br /> But, to answer the question, the diameter probably won't make a hill of beans difference. <br /><br />UFM82

 

[Bondo]

Re: Prop diameter?

In All Reality,..... You have No Choice about the Diameter..... Just Forget about the Diameter Altogether..........<br /><br />You get to Choose the Pitch,+ Style of the blades,+ the # of the blades,+ the Material of the blades,.........<br />But,.......<br />The Engineer/Designer will determine the Diameter for the Application.............<br /><br />Good Luck.....

 

[walleyehed]

Re: Prop diameter?

Bondo is correct for the most part, but there are applications that require more or less diameter and manufacturers are following by offering different props in different diameters.<br />Most of these in larger diameter in SS will be for high mounting (Engine) applications where speed and efficiency is desired.

 

[dy168]

Re: Prop diameter?

Thanks for the response. I measured the prop and it is 14" in diameter. My upgrade to a SS prop is not for speed or performance. I was happy with my orginal alum. prop. But after I took it to a prop shop to repair, the paint just keeps coming off after each trip. It gets to the point its all over the blades. So I have decided to use it as a spare and get a better SS prop and its on sale at iboats.com.