Prop discussion

Designs for inboard or outboard power

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Bill Edmundson
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Re: Prop discussion

Post by Bill Edmundson »


I'll get the calculator out in the morning. At some rpm, blade tip cavitation plays in. A 12" prop. starts having issues at about 4000 rpm. A really good prop. shop can get you above that. (Yes some will disagree with me.)

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Re: Prop discussion

Post by benpetre » ... lator.html

good tool to use

1.23 ratio
5000 pm WOT
assume a 15% slip

Given all the above variables, the 14 gets you to 46mph at WOT
the 12 gets 39mph as long as you dont cavitate above 4k like bill said.

Prop slip may be different between the 3 blade and 4 blade. 15% assumed for discussion
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Re: Prop discussion

Post by Hercdrvr »

I mounted the 14x14 3 blade prop. It has 2.75 inches clearance from the bottom of the hull, is this sufficient?
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Re: Prop discussion

Post by Roberta »

That should be fine.

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Re: Prop discussion

Post by kens »

2.75" is a rather generous clearance, that prop should breathe nicely. run smooth
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Re: Prop discussion

Post by denbrlr »


A 2.75 inch clearance should work well. I am curious, what is the drop of your strut?

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