Would someone explain what

[FRANK THE TANK]

prop pitch means and what going up or down in pitch does to the performance of ones boat? I'm super confussed. I have a 22P prop on my 21 FT boat and am wondering if I would benefit from a different prop.
Thanks for the 411!!!!!!

[HighRoller]

I'm a jet guy but I'll give you the Reader's Digest version. A 21-inch pitch means that theoretically the boat would travel forward 21 inches for each revolution of the prop. Think of it as equivalent to the gear ratio in a car. The bigger the number, the taller the"gear". And of course, it takes more torque to pull more pitch in equal settings.

[HighRoller]

Now if you want an explanation of what prop diameter, blade count and cupping does, I'm lost. Believe it or not these factors can change your planing speed, acceleration and speed at RPM greatly. I just don't know which does what:D

[Rexone]

Very basically the pitch number is the distance forward in inches the prop will travel in one revolution with no slippage. Think of it as gear ratio in a car. More pitch = taller gear. More pitch = more blade angle.
edit>>> oops posted on top of HR... (what he said). :D

[CrazyHippy]

Pitch is fairly easy to explain. The 21" prop will theoretically move the boat 21" per revolutions. A 24" prop will theoretically move the boat 24" per revolution, etc...
It is possible to go to big on propellers, anad not have enough power to turn it.
3 blade props tend to be faster on the top end, but vibrate more, and slip more coming on to plane.
4 blade props will pull harder off the line, but are usually not as fast on the top end.
There are LOTS of other variables (enough to fill a book easily) involved in getting the right prop for your boat, and your wants. Things like rake, cup, diameter, etc.
I would recomend talking to a Prop Shop. R&R prop shop in Henderson gets my buisiness. (702)564-7502
Any other ?'s
BJH

[CrazyHippy]

Originally posted by HighRoller
Now if you want an explanation of what prop diameter, blade count and cupping does, I'm lost. Believe it or not these factors can change your planing speed, acceleration and speed at RPM greatly. I just don't know which does what:D
As a generalization...And as I understand it....
Diameter helps carry weight
Blade count More pulls better, less is faster
Cup Helps influence wether the prop helps to lift the bow of the boat or the stern
Rake does the same, more rake lifts the bow...
Dont take this as gosple, just what i've seen.
BJH

[FRANK THE TANK]

Originally posted by CrazyHippy
As a generalization...And as I understand it....
Diameter helps carry weight
Blade count More pulls better, less is faster
Cup Helps influence wether the prop helps to lift the bow of the boat or the stern
Rake does the same, more rake lifts the bow...
Dont take this as gosple, just what i've seen.
BJH
Thanks for the info. I'll call the guys over in Henderson like you suggested and see what they come up with.

[Kilrtoy]

You have a 22" 4 blade.
From everything Shockwave has told me that is the best all around prop. You can get a little more top end or a little more low end.
But it will sacrafice the other end. So I left my 22 on.

[Seadog]

Pitch is the distance traveled in a revolution as said.
diameter is the amount of grabbing ability, like the tires on a car. A four or five blade prop will give you more prop surface to grab the water, like putting wider tires on the car to get more traction for launching or cornering.
If you want a high speed, you can put a small diameter prop on with a lot of pitch and it will eventually go fast, but take a long time to get there. If you want fast acceleration, you get a lower pitch and more blade area.
Theoretically, the advantage to more blades is increasingly smoother balance, but for most setups 3-4 blades is the maximum needed. When I was testing props for my rig, I finally settled on a 15x16p four blade and a 16x16p three blade. Both worked fine, but overall the three blade was the better of the two. The three blade was what is called a wide blade series, meaning that the blade area is a lot larger than a conventional prop. (work load props have even pitch numbers, which one way to identify a prop with a large blade area).