RE: Pitch vs Diameter
2012/02/13 13:30:16
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Ok, I’m writing this quick before I have to head off to work, so pardon any spelling errors.
I’m assuming that it is an alpha one, with a 1.47:1 reduction in the outdrive. Correct me if I’m wrong.
Your best bet would be a 14.5x17 Stainless vented. Why vented? Why stainless?
Most people stay away from vented or talk dirty about them because they do not fully understand how they work, or what their purpose is. A vented prop allows a heavier boat with an underpowered engine to get onto plane quicker, without sacrificing total top speed. How?
Simple. With a vented prop, there are holes in front of the blades to allow the prop to cavitate. Why do you want your prop to cavitate?
When you are allowing the prop to cavitate at slower forward speeds, it allows the engine to build more rpm and to get it its power curves sooner. That will allow your boat to gain the initial bottom end and plane sooner. Once you boat reaches about 20ish, the water pressure flowing over the prop exceeds the exhaust pressure and seals off the holes.
What makes me say stainless? A 15x19 aluminum and a 14.5x17 stainless are basically the same prop. With that big of a wheel, you get a tremendous amount of deflection. With a stainless wheel, the prop doesn’t deflect as much, and you don’t lose any pitch as the wheel is spinning faster.
Prop dia. vs pitch is about as complicated as it can get. A 17 pitch wheel, is going to move 17 inches forward with 1 revolution. The diameter comes into play with the amount of water volume its moving, not how far forward its moving.
Pm me with a phone number and I will explain father, I apologize about bouncing around everywhere, but there is so much to a simple question.